Contents

GENETIC EVALUATION AND UTILIZATION

Overall progress 5 IR64 compared with recently released ASD16 and other IR varieties 5 A simplified method to classify rice varieties with isozymes

Agronomic characteristics 7 Ratooning ability of IR varieties in Hangzhou, China 7 Performance of CR666 rice cultures 8 Performance of broadcast seeded TM8089 8 Cross compatibility between Guizhou traditional upland sinica varieties

8 Varieties suitable for direct seeding in the Ganges floodplain 9 Evapotranspiration rates of Jaya and Triveni varieties 9 Rice grain dormancy and its alleviation

and short-statured varieties

10 Inheritance of tillering ability in three crosses of upland varieties 11 Performance of ORS26-2014-4 (Lalat), a medium-duration variety 12 Four new rice varieties in Bangladesh 12 Heritability of rolled leaf character

Grain quality 12 Grain quality of some promising mutants 13 Grain quality characteristics of some rice varieties 13 Physicochemical properties of discolored rice grains

Disease resistance 14 Field screening against tungro (RTV) in Lanrang, Indonesia 14 Multilocational screening for bacterial blight (BB) resistance

Insect 15 15 16

16 17

17 17 17

resistance Reaction of rice varieties to the mite Oligonychus oryzae Resistance to whitebacked planthopper (WBPH) in Rajasthan Pothana — a gall midge (GM) resistant variety for endemic areas of Andhra Pradesh Evaluation for brown planthopper (BPH) resistance New sources of resistance to gall midge (GM) and yellow stem borer (YSB) Screening for resistance to yellow stem borer (YSB) Screening rice cultivars against rice whorl maggot (RWM) Modified seedbox screening test to identify field resistance to brown planthopper (BPH)

Cold tolerance

West Bengal 18 Variability in yield and yield components of normal and late-sown rice in

Drought tolerance 19 Drought tolerance of some hybrids and their parents

Adverse soils tolerance 21 Field screening of hybrids for the second crop in acid sulfate soils of

South China

Hybrid rice 22 Early-maturing hybrid rice combinations 22 Morphological characters, seed setting, and dry matter production of A

23 Performance of three new hybrid rices and B lines

PEST CONTROL AND MANAGEMENT

Diseases 24 Leaf blast (Bl) outbreak in dry season rice 25 Purification and serology of ragged stunt virus (RSV) 25 Timing of planting and variety for rice tungro virus disease (RTV) control 26 A scoring system for rice yellow mottle virus disease (RYMV) 26 Crown sheath rot incidence in West Bengal 27 Nitrogen level, cultivar, and R. solani isolate effect on sheath blight (ShB)

28 Bacterial blight (BB) in hilly regions of Nepal 28 Relationship between growth rate, sclerotia production, and virulence of

29 Control of rice pests with phosphamidon 85% WP 30 Effect of low soil phosphorus and pH on bacterial blight (BB)

development

isolates of Rhizoctonia solani Kuhn

Insects 30 Elophila sp? africalis Hampson (Lepidoptera: Pyralidae): A new pest of

30 Leaffolder (LF) population on rice under drought 31 Pest survey in Kalutara district, Sri Lanka 31 Trap crop for green leafhopper (GLH) and tungro (RTV) management 32 Rice thrips Stenchaetothrips biformis (Bagnall) effect on yield 32 Influence of age of crop and time of planting on gall midge (GM)

33 Host plants for yellow rice borer (YSB) Scirpophaga incertulas and white

33 Walking the rice paddy for pest sampling does not affect yield 33 Occurrence of a virulent rice gall midge (GM) Orseolia oryzae Wood-

Mason biotype (?) in Andhra Pradesh, India 34 Some common predators of rice insect pests 34 A new brown planthopper (BPH) biotype in Parwanipur, Nepal 34 Seasonal changes in the stem borer (SB) Maliarpha separatella

35 Influence of cultivation on survival of the Malayan black bug in ricefields 36 Bioassay of Beauveria bassiana and Nomuraea rileyi (Deuteromycotina;

36 Effect of buprofezin in controlling green leafhopper (GLH) and tungro

37 Knockdown of green leafhopper (GLH) by six insecticides 37 Effect of synthetic pyrethroid insecticides on green leafhopper (GLH)

38 Chemical control of rice gall midge (GM) Orseolia oryzivora

azolla in Sierra Leone

incidence

stem borer (WSB) S. innotata

populations

Hyphomycetes) against the rice leaffolder (LF)

(RTV) incidence

and tungro (RTV)

Weeds 38 Herbicides to control weeds in transplanted rice

Other pests 39 Yield loss to rice root nematode Hirschmanniella oryzae 39 Control of rice root nematode with carbofuran

IRRIGATION WATER MANAGEMENT 40 Irrigation regime and rice yield

SOIL AND CROP MANAGEMENT Tissue culture

23 A simple device for mass extraction of rice anthers 41 Mollisol productivity under two management levels 41 Effect of nitrogen source and insect control on growth of a ratoon crop

42 Effect of sesbania straw in a flooded soil on soil pH, redox potential. and

43 Amelioration of highly alkali soil by karnal grass and para grass before

44 Effect of pyrite and fertilizer on rice protein quality 45 Response to nitrogen of rice in sodic soil 45 Comparative efficiency of puddling implements 46 Effect of sodicity and pretransplanting submergence on rice yield 46 Effect of seeding date and seedling age on dry season yield 47 Scarifying seeds of green manure legumes 47 Whole-plant ratooning technique 48 Effect of phosphates on flooded rice 48 Effect of basally applied coated urea on grain yield 49 Applying nitrogen with sesbania 49 Responses of rice to N, P, and Zn in semireclaimed alkali soil 49 Effects of several urea-based N sources 50 Effect of urea supergranule (USG) and grain yield of varieties of different

50 Mussoorie rock phosphate (MRP) effects on yield 51 Weed seedlings transplanted with rice seedlings reduce grain yield

water-soluble nutrients

rice - wheat cropping sequence

durations

51 Nitrogen sources and placement for irrigated rice 51 Phosphorus application in acid-sulfate soil 52 Effect of sulfur source and fertilizer on rice yield 53 Efficiency of phosphorus form combined with organic manure in rice -

53 Effect of Azospirillum on ASD16 rice

RICE-BASED CROPPING SYSTEMS

rice cropping

53 Rice-based fish and vegetable cropping system in coastal saline soils 54 Transplanted aman - potato - maize cropping pattern in Bangladesh

ANNOUNCEMENTS 54 Two IRRI scientists awarded Japan’s top science prize 55 IRGC user guidelines 56 Public health and rice scientists hold conference on waterborne disease 56 New IRRI publications

ERRATA

was planted 3 Apr and harvested on 6 Oct. At harvest, 10 plants from each replication were assessed for yield and yield-contributing characters.

IR64 yielded 5.0 t/ ha, 0.2 t/ ha more than ASD16 and IR60 (Table 1). IR64 and IR62 compare in height, but IR62 takes 5 d longer to mature. The grain of

IR64 is long slender. IR64 is resistant to brown

planthopper (BPH), green leafhopper (GLH), and whitebacked planthopper (WBPH) and moderately resistant to blast (Bl), bacterial blight (BB), and tungro (RTV) (Table 2).

IR64 compared with recently released ASD16 and other IR varieties

S. R. S. Rangasamy. C. A. Palanisamy, K. Natarajamoorthy. S. Palanisami, R. Velusamy, and S. M. Lal, Tamil Nadu Agricultural University (TNAU), Coimbatore, India

IR64 was compared with recently released TNAU variety ASD16 and IR50, IR60, and IR62 in a Summer 1986 trial. The random block replicated trial

Guidelines and Style for

IRRN Contributors

Articles for publication in the International Rice Research Newsletter (IRRN) should observe the following guidelines and style.

Guidelines • Contributions should not exceed two pages of

double-spaced typewritten text. Two figures (graphs, tables, or photos) may accompany each article. The editor will return articles that exceed space limitations.

• Contributions should be based on results of research on rice or on cropping patterns involving rice.

• Appropriate statistical analyses should be done.

• Announcements of the release of new rice varieties are encouraged.

• Pest survey data should be quantified. Give infection percentage, degree of severity, etc.

Style • For measurements, use the International

System. Avoid national units of measure (cavan, rai, etc.).

measure when they follow a number. For example: 20 kg/ha, 2 h/d.

• Express yield data in tonnes per hectare (t/ha). With small-scale studies, use grams per pot

• Express time, money, and common measures in number, even when the amount is less than 10. For example: 8 min, $2, 3 kg/ha, 2-wk intervals.

• Write out numbers below 10 except in a series containing 10 or higher numbers. For example: six parts, seven tractors, four varieties. But There were 4 plots in India, 8 in Thailand, and 12 in Indonesia.

• Write out numbers that start sentences. For example: Sixty insects were put in each cage. Seventy-five percent of the yield increase is attributed to fertilizer.

• Place the name or denotation of chemicals or other measured materials near the unit of measure. For example: 60 kg N/ha, not 60 kg/ha N; 200 kg seed/ha, not 200 kg/ha seed.

• Use common names — not trade names — for chemicals.

• The US$ is the standard monetary unit in the IRRN. Data in other currencies should be converted to US$.

• When using acronyms, spell each out at first mention and put the specific acronym in parentheses. After that, use the acronym throughout the paper. For example: The brown planthopper (BPH) is a well-known insect pest of rice. Three BPH biotypes have been observed in Asia.

• Abbreviate names of months to three letters: Jun, Apr, Sep.

• Define in the footnote or legend any nonstandard abbreviations or symbols used in a table or figure.

bibliography.

• Abbreviate names of standard units of

(g/pot) or g/row.

• Do not cite references or include a

Genetic Evaluation and Utilization OVERALL PROGRESS

Table 2. Resistance a of ASD16 and 4 IR varie- ties to pests and diseases at Coimbatore, India, 1986 summer.

Reaction to Reaction to insects diseases

Variety BPH GLH WBPH BB B1 RTV

IR50 S S S S S MR IR60 S MR S S R R IR62 R R R R RR IR64 R R R R RR ASD16 S S S MR MR S

a R = resistant, MR = moderately resistant, S =

Table 1. Performance of ASD16 and 4 IR varieties at Coimbatore, India, 1986 summer.

Variety Duration Plant Tillers/ Grains/ Empty Grain Straw 1000- Yield

(d) (cm) ht plant panicle grains/ yield yield grain

panicle (g/plant) (g/plant) wt (g) (t/ha)

IR50 110 69.5 10 111 IR60 115 72.8 11 108 IR62 125 82.1 9 110 IR64 120 83.1 11 118 ASD16 115 97.2 8 102

CD 3.5 2.2 9.5

23 12.4 9.1 21.2 4.6 20 11.7 8.9 21.3 4.8 20 15.3 13.6 23.9 4.6 16 18.2 12.9 26.9 5.0 19 16.7 15.4 24.2 4.8 – 3.4 – 1.5 –

A simplified method to classify rice varieties with isozymes

J. C. Glaszmann, Institut de Recherches Agronomiques Tropicales et des Cultures Vivrieres, Centre International de Recherche Agronomique pour le Developpement, and Plant Breeding Department, IRRI

Analyses of isozyme variation at 15 to 21 loci among traditional O. sativa rices from all continents have led to the identification of 6 varietal groups: indica (group I); japonica, with its temperate

and tropical forms (group VI), and 4 marginal groups restricted to the north of the Indian subcontinent (groups II to V). The method used to determine the classification of a given variety involves at least 15 loci and requires electrophoretic survey of at least 10 enzymes.

We have developed a simplified procedure based on five diagnostic genes which permit classifying most varieties. These genes are Pgi-1 and Pgi-2, which encode phosphoglucose isomerases, and Amp-3, Amp-2, and Amp-1, which

IRRN 12:3 (June 1987) 5

susceptible.

A simple method to classify rice varieties with isozymes, using their genotypes at the 5 loci Pgi-1, Pgi-2, Amp-3, Amp-2, and Amp-1. IRRI, 1987.

encode aminopeptidases efficient with leucyl -ß- naphthylamide, alanyl -ß- naphthylamide, and both substrates. The enzymes are extracted by grinding a single plumule in a few drops of water and are separated by 4 h electrophoresis at 15 V/cm in a 14% starch gel, with a

6 IRRN 12:3 (June 1987)

Tris (0.009M)-Histidine (0.005M) gel buffer, pH 8.0, and a Tris (0.400M)- Citrate (0.105M) electrode buffer, pH 8.0. They are stained using standard procedures.

translated in terms of loci and alleles. The resulting zymograms are

These data are used to assign a given variety to one of the groups. An algorithm with five steps, corresponding to the five loci, where the criteria taken into consideration are the alleles of the variety at these loci, is used (see figure).

The original and the simplified

Performance of CR666 lines at Coimbatore, India, 1986.

Line Duration(d)

Mean Mean Panicle plant ht

(cm) plant (cm) tillers/ length

Yield (t/ha)

CR666-14 CR666-18 CR666-36-4 CR666-37-38 CR666-119

75 74 75 73 75

68 71 66 87 65

6 8 6 6 7

17 17 16 21 17

1.3 1.9 0.8 1.5 0.9

methods were compared using a sample of more than 3,000 traditional varieties. The classification coincided in 99% of the cases. In the other 1%, rices fell into one group in one case and were

classified intermediaries in the other case. A similar finding was observed

among modern varieties produced by hybridization within a group. Of 87 varieties whose parentage involves at

least 2 different groups, only 4 (5%) gave different results using the 2 methods.

The simplified method is highly reliable. It is fast, cheap, and requires no sophisticated equipment.

Genetic Evaluation and Utilization AGRONOMIC CHARACTERISTICS

Ratooning ability of IR varieties in Hangzhou, China

Qiu Baiqin and Jin Qingsheng, Crop Institute, Zhejiang Academy of Agricultural Sciences, Hangzhou, China

We evaluated 28 IR varieties, from IR5 to IR64, for ratooning ability. Pregerminated seeds were sown on 18 Apr 1986 in a screenhouse and 8 plants of each variety were transplanted on 17 May at 20- × 15-cm spacing. At maturity, plants were cut to 15-cm height and scored for ratooning ability 15 d after cutting.

IR29, IR30, IR43, and IR64 had relatively high ratooning ability; ratoon crops yielded about 50% of main crops (see table). In 13 varieties, ratooning was intermediate; ratoon crops yielded 20- 30% of main crops. In seven varieties, the ratoon crops did not head because of the long growth duration of the main crop and subsequent low temperatures during the ratoon crop. Main crop and ratoon crop growth durations and yields did not correlate.

Performance of CR666 rice cultures

G.A. Palanisamy, K. Natarajamoorthy, and S. Palanisamy, School of Genetics, Tamil Nadu Agricultural University, Coimbatore 3, India

To identify a very short-duration variety that can fit into the 60-d fallow between 2 turmeric crops in Kalingarayan canal tract, we tested 5 promising lines of CR666. The entries were direct seeded on 16 Jul 86 in a randomized block design replicated three times. Because no local variety is in the 60-d duration

Average duration and grain yield of IR varieties in main crop and ratoon crop. Hangzhou, China, 1986.

Main crop Ratoon crop Variety

Ratoon scale

Maturity Yield Maturity Yield (d) (g/plant) (d) (g/plant)

IR5 IR8 IR20 IR22 IR24 IR26 IR28 IR29 IR30 IR32 IR34 IR36 IR38 IR40 IR42 IR43 IR44 IR45 IR46 IR48 IR50 IR5 2 IR54 IR56 IR5 8 IR60 IR62 IR64

171 167 164 145 123 126 111 118 119 172 148 120 134 155 164 135 131 141 151 167 114 130 133 119 110 120 143 126

14.9 15.7 14.6 14.5 16.5 13.1 16.2 11.7 12.4 14.4 16.3 15.7 12.6 12.8 11.7 12.3 11.4 11.9 13.0 11.6 11.9 11.6 13.0 14.8 12.1 12.9 13.8 12.5

– –

48 56 46 52 47 50

44 48 50

–

–

–

42 49 51 41

50 54 57 43 42 41 45 51

–

–

– –

4.2 4.5 3.8 1.8 5.8 6.4

3.8 4.1 2.4

–

–

–

6.0 2.7 3.3 2.6

1.5 2.9 3.0 2.9 1.7 1.4 2.6 6.1

–

–

– – – 5 5 5 9 1 1

5 5 5

–

– – 1 5 5 5

9 5 5 5 9 9 5 1

–

group, a local check could not be included.

The 5 lines, which reportedly mature in 60 d at Cuttack, took about 15 d longer at Coimbatore, perhaps because

of the difference in latitude and elevation. Cuttack is situated 20° 30'N at 23 m, Coimbatore at 11 °02' N at 431 m. CR666-18 gave the maximum yield, followed by CR666-37-38 (see table).

IRRN 12:3 (June 1987) 7

Varieties suitable for direct seeding in the Ganges floodplain

B.K. Singh and R.K. Roy, R.A.U. Campus, Bihar Agricultural College, Sabour 813210, Bihar, India

The Ganges River floodplain, formed through soil erosion and deposits, is estimated to total 0.24 million ha. The land is subjected to periodical flooding

Performance of broadcast seeded TM8089

M. Subramanian, A.P.M.K. Soundararajan, and V. Sivasubramanian, Tamil Nadu Rice Research Institute, Aduthurai, Tamil Nadu, India

TM8089 is a high-yielding blast-tolerant red rice selection from TKM9. It was isolated at the Paddy Experiment Station, Tirur, to replace highly blast- susceptible TKM9. We compared TM8089, which is suitable for rainfed lowland cultivation, and TKM9 broadcast seeded and transplanted in 200-m 2 observational plots.

Broadcast seeding was at 100 kg seed/ ha. Transplanting was at 60 kg seed/ ha. Thinning and gap filling were done in the broadcast plots; transplanting was at 2 to 3

Cross compatibility between Guizhou traditional upland sinica varieties and short-statured indica varieties

Shen Fu-Chen, Chen Wen-Qinag, and Pan Jian-Hui, Rice Research Institute, Academy of Agriculture Science, Guizhou Province, China

Cross compatibility between 296 Guizhou traditional upland sinica varieties and 3 short-statured indica varieties was tested in 663 F 1 combinations in 1985.

A number of the local upland sinicas have high cross compatibility with short- statured indicas. The upland sinicas have higher cross compatibility with the short-statured indicas than with lowland sinicas (Table 1). They also have distinctly higher cross compatibility with short-statured Guichao 2 than with common short-statured sinicas (Table 2). The high and low cross compatibility between sinicas and indicas are negatively correlated with the latitudes and elevations of the origins of the sinicas and positively with mean temperature and >10 °C cumulative 1-yr temperature of the places of origin. The closest relationship is with latitude.

8 IRRN 12:3 (June 1987)

Comparison of TM8089 and TKM9 broadcast and transplanted. a Tamil Nadu, India.

Broadcast seeding Transplanting

TKM9 TM8089 TKM9 TM8089 Character

Plant height (cm) 93.8 95.2 99.0 (5.696)** 103.6 Productive tillers 5.0 5.0 10.4 (4.472)** Panicle length (cm) 20.6 (1.963)** 18.6 23.2 (6.321)**

10.6 22.4

Panicle weight (g) 3.0 3.0 3.0 (8.179)** 71.0 (2.855)**

3.2 Grains/panicle 76.0 93.0 (4.989)** Yield (t/ha)

97.0 2.6 3.1 5.0 5.2

Difference (%) – 17.5 – 5.5

a t values in parentheses are highly significant.

seedlings/hill, 15- × 10-cm spacing. Management practices were common for both planting treatments.

from each plot and plant height, productive tillers, panicle length, panicle weight, and grains/ panicle were recorded. Differences between direct seeding and transplanting were distinct

Twenty hills were selected at random

(see table). All traits were lower under broadcast seeding, in particular, number of productive tillers.

TM8089 was better than TKM9 in all traits except panicle length. Its higher yield is attributed to more grains per panicle under broadcast seeding and to more grains per panicle and higher panicle weight under transplanting.

Table 1. Distribution of cross compatibility (CC) between Guizhou upland sinica varieties and short- statured indica varieties. China, 1985.

>50% CC >60% CC >70% CC >80% CC >90% CC Male parent Tota1

(no.) no. % no. % no. % no. % no. %

Lowland rice 545 294 53.94 151 27.71 55 10.09 11 2.02 Upland rice 118 81 68.64 45 33.14 22 18.64 9 7.63 3 2.5

Total 663 375 56.56 196 29.26 77 11.61 20 3.02 3 0.45

Table 2. CC of short-statured Guichao 2 with local upland sinica and common short-statured sinica rice varieties.

F1 distribution (no.) F 1 CC Male parent

Total > 60% CC 170% CC Highest Lowest Mean

Local upland sinica 22 2 1 72.52 30.63 49.90 Common short-statured 24 0 0 50.36 10.87 33.69

sinica

in the wet season and crops are generally grown in the winter season. With the introduction of bamboo boring, another crop in the stabilized floodplain in the summer season before flooding has become possible.

As a short-duration summer rice crop after winter crop harvest, transplanted, irrigated Pusa 2-21 and Pusa 33 performed well and were harvested before flooding started. But summer rice

in these areas is not catching on because Plant height, days to heading, grain yield, and yield attributes of 9 direct-seeded varieties, Bihar,

of the costs of transplanting and India, summer 1985.

Variety irrigating. An early-maturing rice variety khat could be direct seeded and grown with limited irrigation is desirable.

We evaluated the performance of 11 IET6148 early-maturing rice varieties under direct ES1-1-1

seeding with limited irrigation in Ziauddinpur floodplain. The trial was in IET7564 a randomized block design with three IET7613

replications. Soil was sandy loam with Cauvery medium fertility. Seeds at 80 kg/ha were Pusa 33 sown 10 May 1985 in rows 15 cm apart. Fertilizer at 80-17.5-20 kg NPK/ha was applied. One presowing irrigation and two irrigations during the dry spell were given. The crop received 64 mm rainfall in 7 d in May, 222 mm in 18 d in Jun, and 387 mm in 23 d in Jul.

Pusa 2-21 and Hathi Jhulan failed because of a severe attack of brown leaf spot disease. Varieties ES1-1-1,

ES1-2-3 IET7617

ES21-2-1

Plant ht

(cm)

85.2 86.0 78.7 82.2 96.2 91.3 81.2 84.3 88.3

Days to 50%

heading

98 66 66 91 66 92 85 86 98

Panicles/m 2

129 122 144 127 135 124 116 117 114

Panicle length (cm)

18.4 14.4 15.1 18.4 21.3 18.9 14.5 18.8 18.1

CD (0.05) 6.7 14

ES1-2-3, and IET7564 were the earliest to reach 50% heading, 66 d after sowing (see table). Heading time in general was 15-20 d longer than in wet season, perhaps because of soil moisture stress during early crop stages.

IET7564 had significantly higher

Total spikelets/

panicle

64.3 68.2 66.1 63.0

118.3 65.8 65.7 74.2 74.9

Filled spikelets/

panicle

47.0 5 8.5 56.5 46.1

100.3 48.6 51.3 54.6 56.3

1000- grain wt (g)

21.6 18.7 18.2 21.3 20.0 22.0 19.0 20.9 21.4

Grain yield (t/ha)

0.9 1.2 1.5 0.9 2.1 0.8 1 .0 1 .0 1.1

1.4 6.9 6.0 1.0 0.6

grain yield because it had more panicles/ m 2 and filled spikelets/ panicle. This semitall variety develops sufficient foliage in early stages to smother weeds. It has good grain quality and matures within 90 d, for harvest before floods in early Aug.

Evapotranspiration rates of Jaya and Triveni varieties

M.A. Hassan and V. R. Ramachandran, Regional Agricultural Research Station (RARS), Pattambi 679306; and J. U. Nair, Auxillary Evapotranspiration Observatory, Indian Meteorological Department, Pattambi 679306, Kerala, India

The varieties were not observed average evaporative demand of the simultaneously, but were compared on atmosphere. the basis of daily mean ET in relation to ET of Jaya was 41% higher than PET

in Jun-Sep (kharif) and 46% higher in Table 2. Growth parameters of Triveni and Jaya. Oct-Jan (rabi). ET of Triveni was 41% Kerala, India, 1986 kharif. higher than PET in Jun-Sep and 58%

higher in Oct-Jan (Table 1). Jaya and Leaf area index width angle a Triveni had similar ET during kharif,

Leaf Leaf

(mm) but Triveni used 0.14 mm/d more water

We studied evapotranspiration (ET) of 70 d after sowing b

Jaya (120 d) and Triveni (105 d) based Jaya 4.0 d 8.0 e 170° d Triveni during rabi may have been Triveni 6.3 7.5 18°

on data collected 1978-85 at RARS, Pattambi (10°48'N, 76°12'E). ET was

Flowering phase c

Jaya 4.2 e

measured using two sets of volumetric Triveni 4.7

than Jaya during rabi. The higher ET of

because it had higher leaf area index and leaf angle and smaller leaf width than Jaya (Table 2).

lysimeters, and potential ET (PET) was a 70 d after sowing and 10 d after flowering. computed using the Blaney-Criddle b Triveni and Jaya were sown on the same day. formula as modified by Doorenbos and Rice grain dormancy and its Pruitt. Soil was lateritic sandy loam.

at the 1% level. e Not significant. alleviation

Table 1. Varietal variation in ET rates in relation to average PET. Kerala, India, 1986 kharif and rabi.

Kharif Rabi

Variety ET PET Percent increase ET PET Percent increase (mm/d) (mm/d) of ET over PET (mm/d) (mm/d) of ET over PET

Jaya a 4.95 3.51 41 6.05 4.15 46 Triveni b 4.90 3.47 41 6.19 3.93 58

Difference in ET +0.05 –0.14 rates in relation to av PET

a Av of 3 seasons for kharif and 2 for rabi. b Av of 5 seasons each for kharif and rabi.

A. Kapur, J. Kaur, and H. L. Sharma, Seed Research and Production Unit, Plant Breeding Department, Punjab Agricultural University, Ludhiana, India

Seeds of IR8, Jaya, PR106, PR4141, Basmati 370, and Punjab Basmati I were collected immediately after harvest, dried to 12% moisture, and kept under ambient conditions in cloth bags. We began germination tests immediately after harvest, then every 7 d until seeds

IRRN 12:3 (June 1987) 9

c Av of 3 stages; 1 wk before flowering, at flowering, and 10 d after flowering. d Significant

8.9 d 16° d

7.7 18°

attained more than 80% germination. Under ambient conditions, the coarse

and semifine grain varieties broke their dormancy rapidly (56–63 d) compared to superfine grain Basmati 370 and Punjab Basmati I (132–140 d) (Table 1). The fine grain varieties that matured and were harvested under low temperatures broke dormancy slowly; the coarse and semifine grain varieties that encountered slightly higher temperatures during maturation and harvest lost their dormancy rapidly. It appears that temperature fluctuations near full maturity and at harvest contributed quantitatively to the dormancy barriers.

To break dormancy, we presoaked seeds in GA 3 , KNO 3 , and water at 25°C for 24 h and applied a heat treatment at 50oC in the oven for 24, 48,72, and 96 h.

Water soaking showed negligible results (Table 2), indicating that dormancy barriers are not leachable. Presoaking seeds in GA 3 (500 pg/ml) or KNO 3 (500 µl/ml) broke dormancy in all varieties. Heat treatment at 50oC for 96 h was most effective in breaking dormancy. The treatments which broke the dormancy appeared to act at the hull level by inhibiting O 2 absorbing systems and at the embryo level by enhancing O 2 availability and removing inhibitors. A two-block hypothesis is posited: one block seems to be at the husk level and one at the embryo level.

Inheritance of tillering ability in three crosses of upland varieties

A. Faye, M. Gningue, and O. Mane, Institut Senegalais de Recherches Agricoles (ISRA), Djibelor, Senegal

Tiller number at 40 d after seeding (DAS) is indicative of the early growth vigor essential to an early-maturing genotype. We studied allelic relationships, estimates of heritability, and residual heterosis for number of tillers at 40 DAS in 3 F 2 populations of crosses with upland rice varieties that included traditional Abdoulaye Mano, and Barafita from Senegal.

In all F 2 populations, heritability

10 IRRN 12:3 (June 1987)

Table 1. Germination of rice varieties during postharvest storage under ambient conditions. Ludhiana, India.

Variety Germination (%) at indicated days after harvest (DH) Dormancy (d)

0 7 14 21 28 35 42 49 56 63 DH DH DH DH DH DH DH DH DH

PR106 36 40 45 48 56 68 72 76 79 86 IR8 24 30 38 44 55 64 68 72 78 82 Jaya 24 28 32 40 47 54 62 69 76 90 PR4141 58 60 64 67 70 73 75 78 80 88

Coarse and semifine grain

56-63 56-63 56-63 56-63

0 7 63 70 98 105 112 119 125 132 140 DH DH DH DH DH DH DH DH DH DH

Superfine grain

Punjab Basmati 1 2 5 15 20 28 33 38 45 63 75 85 132-140 Bas 370 – 2 5 12 20 42 60 75 75 88 92 132-140

Table 2. Treatments to break dormancy and enhance germination. Ludhiana, India.

Treatment

~

Germination (%)

PR106 IR8 Jaya PR 4141 Pb Bas 1 Bas370

Control (initial germination) 36.6 24.3 24.3 50.6 Water soaking (24 h) 38.6 32.3 30.0 60.0 GA 3 soaking (24 h)

100 µg/ml 57.3 52.0 53.3 69.0 200 µg/ml 71.6 72.0 68.3 77.6 500 µg/ml 86.0 83.3 91.3 95.6

100 µg/ml 43.3 37.3 40.0 59.3 200 µg/ml 65.6 58.0 59.6 71.0 500 µg/ml 81.0 80.3 80.6 81.0

24 h 55.0 52.3 61.0 64.6 48 h 70.3 68.3 76.3 77.0 72 h 81.0 79.3 84.0 89.0 96 h 93.0 92.6 94.3 92.0

LSD P = 0.05 6.3 6.5 6.4 5.0

KNO 3 soaking (24 h)

Heat treatment (50°C)

2.0 7.6

54.6 70.6 85.6

11.3 46.0 76.6

36.0 49.0 67.3 81.3

7.7

– 8.3

50.6 63.0 87.3

10.3 39.3 71.6

23.3 47.6 70.6 80.0

5.8

Means, ranges, mean square, heritability coefficients, and residual heterosis for number of tillers in the F 2 of 3 crosses. ISRA, Senegal.

Population Observations Mean Range Mean square Heritability Residual

(no.) coefficient (H) heterosis

IR12624-65-2 30 IRAT144 28

IRAT144 50 Abdoulaye Mano 52

IRAT144 52 Barafita 52

F 2 160

F 2 160

F 2 160

6.70 3.14 6.11 4.14 4.83 5.50 4.80 5.57 5.52

2–13 7.87 1– 8 4.27 1–19 13.69 57.68% 1–10 9.87 1–15 32.69 1–16 40.39 55.54% –18.45 1– 9 5.33 1–11 8.45 1–24 19.58 65.73% –6.50

–4.32

exceeded 50% for the character studied. higher tillering potential, than to the In the IR12624-65-2/IRAT144 F 2 , more IRAT144 parent (see table). The plants showed tiller numbers closer to distribution of F 2 plants was bimodal the IR12624-65-2 parent, which has the (see figure). Adjusting observed data to

Distribution of numbers of tillers 40 DAS in the F 2 of 3 crosses of upland varieties. ISRA, Senegal.

the theoretical level for 1 gene parental values. The weak expression of numbers at 40 DAS varied segregation (75–25%) gives a highly the tiller number character seems to continuously. Data could not be used to significant c 2 . influence moderate tiller numbers most. test goodness of fit with expected

In IRAT144/Abdoulaye Mano, This explains why the residual heterosis segregation ratio. The distribution environmental variance undoubtedly was negative. skewed more toward higher tiller contributed to the continuous variation In the IRAT144/Barafita F 2 , tiller numbers than it did in Barafita. in the F 2 plants, which corresponds to

Performance of ORS26-2014-4 Yield performance and reactions to insect pests of 24 promising rice cultures. Chiplima, Sambalpur, India, 1986.

(Lalat), a medium-duration variety Plant Days to

S. K. Panda, N. Shi, and K. C. Mohapatra, Culture

Grain Caseworm Leaffolder Whitehead ht 50% Panicles/m 2 yield damage a damage a damage a

(cm) flowering (t/ha) (%) (%) Regional Research Institute, Chiplima, Sambalpur 768026, India ORl58-7-1 99.5 99 238.7 1.8 1.7 11.2

ORl96-2 11.1

74.7 99 345.0 2.1 0.7 7.5 7.5 OR131-5-8 84.0 92 292.0 1.2 0.3 15.3 15.3

ORS26-2014-4 (Obs 677/IR2071 //Bikram/ W1263), popularly called Lalat, is a 135-d variety. We compared it with 23 promising rice cultures of similar duration. The trial had 30-d-old seedlings transplanted 20 Feb 1986 at 20- × 15-cm spacing in 6.5-m 2 plots, in a randomized block design with 3 replications. Fertilizer was 80-40-40 kg NPK/ha. Pest infestation was measured at peak incidence.

Lalat performed best with a yield of 4.3 t/ha (see table). Its grain is medium bold with white kernel. The plant was 85.3 cm tall, flowered in 97 d, and produced 276 panicles/m 2 . It was resistant to caseworm, leaffolder, and stem borer at heading.

NDU80 96.7 97

KM6 78.0 88 RP1570-6-5-4-1 88.8 95

UPR79-123 85.5 95 UPR103-44-2 81.3 101 OR268-408-5 87.8 110 NDR302 92.7 99 RP1570-44-1 87.3 95 RP1699-174-97-1 99.0 97 RP1699-183-133-1 97.2 106 RP1699-26-1-1 94.3 104 UPR231-28-1-2 80.3 91 RP2151-40-1 90.0 102 RP2151-21-22 96.5 103 RP1832-23-3-4 74.5 88 IR18348-36-3-3 89.3 92 Rasi 83.5 90 IR36 78.0 90 RP2240-153-1-51 79.0 92 ORS26-2014-4 85.3 97

(Lalat) ORS26-2008 87.0 99

270.3 211.0 257.7 236.3 232.3 202.7 310.3 306.0 236.7 326.0 348.3 290.3 338.3 295.0 296.0 255.3 225.0 229.0 215.7 275.7

265.3

2.4 1.7 1.5 0.3 1.8 0.7 1.5 1.3 1.7 4.3 1.2 1.3 1.9 1.7 2.3 0.3 1.8 0.3 1.3 0.3 1.9 0.7 2.5 1.3 3.7 1.7 3.0 0.7 1.5 0.3 2.4 0.7 2.1 1.3 2.0 0.3 2.1 0.7 4.3 0.3

2.2 0.7

a By the Standard evaluation system for rice.

11.0 11.0 13.3 13.3 15.7 15.1 11.7 11.7 12.5 12.5

8.9 8.8 11.2 10.0 13.2 13.2 15.1 15.1 11.0 11.2 14.6 14.6 11.7 11.7

8.2 8.2 5.8 5.8

13.5 13.5 10.7 10.7 14.4 11.1 10.3 10.0 14.6 14.5

9.9 9.9

10.9 10.9

IRRN 12:3 (June 1987) 11

Four new rice varieties in Bangladesh

M.M. Ullah and N.A. Khondaker, Regional Agricultural Research Station, P.O. Hathazari, Chittagong, Bangladesh

Four new varieties (BR12, BR14, BRl5 and BR16) were compared to popular short duration Purbachi and BRI for the first wet season crop.

transplanted on 15 May and harvested in Aug 1985. Urea, triple superphosphate, and muriate of potash were applied at 80, 30, 35 kg NPK/ha. BR14 and BR12 produced the

Thirty-day-old seedlings were

genes but in other combinations, the by 14 pairs of dominant genes (see rolled leaf character was controlled table).

Inheritance of rolled leaf character in crosses. Guizhou, China, 1984-85.

F 2 flag leaf Cross F 1 P>

flag leaf Rolled- Flat- Rolled:flat leaf leaf

plants plants

R503/Guizhou 2 Flat 138 R503/Qian Yi 272

445 Flat

1:3 200

0.5445 0.30 652

R503/Guang er ai 104 Flat 1:3

135 1.0577

391 0.30

R524/Guizhou 2 Flat 126 456 1:3 0.1243 0.70

R524/Qian Yi 272 1:3 3.4845

Flat 129 0.05

385 R524/Guang er ai 104 Flat

1:3 194

0.0025 0.80 610

R556/Guizhou 2 1:3 0.3251 0.50

Rolled 630 7 63:1 0.8885 R556/Qian Yi 272 Rolled 468 2 256:1

0.30

R556/Guang er ai 104 Rolled 354 5 63:1 0.0410 0.80 0.0140 0.90

significantly highest yields, Purbachi the lowest. BR14 matured 6 d later than Purbachi but gave 38% higher yield (see Genetic Evaluation and Utilization table).

GRAIN QUALITY Performance of new rice varieties at the Farm- ing Systems Research site, Hathazari, Chitta- gong, Bangladesh, 1985.

Grain Variety yield a

(t/ha)

Duration (d)

BR16 4.10 cd 124 BR15 4.28 bc 126 BR14 4.81 a 122 BR12 4.66 ab 128 BR1 3.68 cd 113 Purbachi 3.49 d 116 a Values followed by a common letter do not differ Significantly at the 5% level of probability.

Heritability of rolled leaf character

Shen Fu-Chen, Liu Chuan-Xiu, and Pan Jian- Hui, Academy of Agricultural Sciences, Guizhou Province, China

Heritability of the rolled leaf character has been found to be controlled by a pair of mainly recessive genes.

Using R503, R524, and R556, with the rolled leaf, as female parents, and Guizhou 2, Guang er ai 104, and Qian Yi 272, with a flat leaf, as male parents, we observed the F 1 and F 2 in 1984 and 1985.

In some combinations, the character seemed to be controlled by a pair of

Grain quality of some promising mutants

M.A. Sagar and M. Ashraf; Rice Grain Quality Lab, National Agricultural Research Centre, Islamabad, Pakistan

We examined the physicochemical characteristics of two mutants developed at the Nuclear Institute for Agriculture and Biology, Faisalabad. DM16-5-1

from Basmati 370 has significantly higher yield (29.16%) than its parent. FG6 from IR6 has higher head rice recovery (8%) than its parent.

No significant differences were found between parent and mutant for 100-grain weight, grain length, breadth, size and shape, elongation ratio, amylose content, and gelatinization temperature. However, the length to breadth ratio for both groups differed

Quality characteristics of milled rice of mutants and their parents. Islamabad, Pakistan.

Characteristic

Aromatic Non-aromatic

Basmati DM16-5-1 Statistical IR6 FG6 Statistical 370 significance a significance a

100-grain weight (g) Grain length (mm) Grain breadth (mm) Length: breadth Grain size and shape

Cooked grain length (mm) Elongation ratio Chalkiness score Whiteness Amylose content (% dry basis) Protein content (% N × 5.95) Alkali spreading value Gel consistency (mm) Gelatinization temp (°C) Aroma

1.5 6.6 1.6 4.2

Long Slender

13.3 2.0 5 .0

40.4 20.0

8.4 5.2

46.8 70.5

Strong

1.5 6.6 1.7 3.9

Long Slender 12.4

1.9 8 .0

41.2 19.3

7.3 4.3

50.8 72.1 Moderately strong

NS NS NS

S – – S

NS HS NS NS HS HS HS NS

1.8 7.0 2.0 3.6

Long Slender

13.2 1.9 5.0

46.0 29.6

8.0 7.0

59.8 67.0

None

1.8 1.2 1.8 4.0

Long Slender

13.4 1.8 1.5

42.8 28.1

7.2 7.0

47.5 66.0

None

NS NS NS

S – –

NS NS HS

S NS HS NS HS NS

a S = significant at the 5% level, HS = significant at the 1% level, NS = nonsignificant.

12 IRRN 12:3 (June 1987)

c 2

Physicochemical properties of

significantly (see table). Chalkiness be taken as similar because they ranged FG6, it was the same as in IR6. Aroma scores, protein content, and gel from 41 to 60 mm. was strong in Basmati 370 and consistency tests also were significantly Cooked grain length of DM16-5-1 moderately strong in DM16-5-1. 1R6 different. But gel consistency values can was less than that of Basmati 370; in and FG6 had no aroma.

Grain quality characteristics of some rice varieties

A. N. Kihupi, Sokoine University of Agriculture, Crop Science Department, P. O. Box 3005, Morogoro, Tanzania

We evaluated 36 lines and varieties for yield and grain quality characteristics. Plot size was 3.6 × 2 m with 20- × 20- cm plant spacing.

Afaa Mwanza and M38 had the highest grain yields, followed by IR46,

IR36, M40, IR42, and 1ET2379; CR1005 and IR5 had the lowest (see table).

significantly in grain length to breadth ratio: the highest ratio was for Faya Theresa (slender), and the lowest ratio for F46 (medium). Supa India had the longest grains (extra long) and Cross 10 the shortest (medium).

Amylose content varied, 19-28%. Popular varieties in Tanzania — Afaa Mwanza, Faya Theresa, Supa India,

The materials tested differed

and Kihogo Red — had intermediate amyloses, as do a number of the introduced varieties.

It was not possible to separate high- amylose rices into those with soft and hard gel consistency because laboratory facilities are limited.

Individuals, organizations, and media are invited to quote or reprint articles or excerpts from articles in the IRRN.

Grain yield and quality characteristics of some rice varieties. Ngerengere, Tanzania.

Grain Grain Size Length: Amylose Line or variety yield length category breadth Shape content Type

(t/ha) (mm) (%)

M38 7.2 7.4 Long 4.5 Slender 21 Intermediate Afaa Mwanza M40

7.1 6.7 Long 3.4 Slender 24 Intermediate 6.9 7.0 Long 3.5

IR46 Slender 2.4 Intermediate

6.8 6.6 Long 3.4 Slender 22 Intermediate IR36 6.6 5.9 Medium 3.4 Slender 28 High IR42 6.5 6.8 Long 2.7 Medium 23 Intermediate IR48 6.3 6.3 Medium 3.0 Slender 23 Intermediate IET2379 6.3 6.4 Medium 3.3 Slender 28 High TOX502-25-115 6.1 7.4 Long 3.2 Slender 20 Low IR34 6.0 7.1 Long 4.4 Cross 14

Slender 25 High

M26 6.0 6.01 Medium 2.6 Medium 21 Intermediate 6.0 6.5 Medium 2.7

Faya Theresa Medium 23 Intermediate

5.9 6.5 Medium 4.7 Cross 3

Slender 22 Intermediate

F19 5.7 6.01 Medium 3.4 5.6 5.8 Medium 3.3

Slender 22 Intermediate Slender 22 Intermediate

TOX494-5-1-B-2 5.6 7.5 Long 4.1 M48

Slender 22 Intermediate 5.4 6.7 Long 3.8 Slender 19 Low

Cross 10 5.3 5.7 Medium 3.1 Supa India

Slender 24 Intermediate 5.3 7.7 Extra long 3.6 Slender 23 Intermediate

Kihogo Red 5.1 7.1 Long 3.6 IR3274-348-1-6 5.1 5.7 Medium 2.8

Slender 24 Intermediate Medium 25 High

M9 4.9 6.6 Long 3.7 Slender 28 High

Cross 7 4.8 5.9 Medium 2.7 4.8 6.6 Long

Medium 21 Intermediate

F46 3.7 Slender 21 Intermediate

4.8 6.5 Long 2.6 Medium 25 High M50 4.5 6.8 Long 4.2 BKN6986-147-6 4.4 7.1 Long

Slender 26 High

IITA63-84 3.0

4.4 7.4 Long Slender 26 High

IR5931-81-1-1 3.2 Slender 24 Intermediate

4.2 6.7 Long 3.6 M13 4.1 6.7 Long 3.5 Slender 20 Low

Slender 28 High

Kinandang Patong 3.5 7.30 Long IR1539-823-1-4 3.5 6.69 Long

3.6 Slender 23 Intermudiate 3.6

Ram Tulasi Slender 26 High

3.2 6.70 Long CR1005

3.2 2.0 6.61 Long 3.5

Slender 24 Intermediate

IR5 2.1 6.46 Medium 3.4 Slender 23 Intermediate Slender 22 Intermediate

Mean CV (%)

5.2 6.65 3.4 19.4 5.99 7.7

B57C-MD-10-2 4.9 6.5 Medium 3.3 Slender 25 High

IR4570-124-3

23

discolored rice grains

E. P. Navasero and M. D. Window, International Institute of Tropical Agriculture, P.M. B. 5320, Ibadan, Nigeria

Discolored grains of ITA307 were obtained from IITA’s high rainfall station at Onne in southern Nigeria. The samples were divided into healthy (glume discoloration 1-5%) and discolored (more than 5% discolored) grains.

Part of each sample was parboiled in the laboratory. (Parboiled rice is widely accepted in Nigeria and other West African countries.)

Discolored grains had lower dry weights for rough and brown rice than healthy grains. Head rice yield is also low (see table).

After parboiling, milling yields, translucency, and hardness improved for both healthy and discolored grains. Discolored glumes did not necessarily result in discolored milled rice. However, parboiling accentuated discoloration.

In ITA307, cooking time and gelatinization temperature were not much affected by discoloration. Amylose content slightly decreased in discolored grains.

IRRN 12:3 (June 1987) 13

Physicochemical properties of parboiled and unparboiled discolored grains. Ibadan, Nigeria.

Discolored parboiled CV LSD

(5%) Healthy Discolored Healthy

Property raw raw parboiled

Dry weight (mg)/grain Rough rice 28.8 26.8 28.4 Brown rice 24.6 21.9 24.4

Milled rice 73.6 71.3 79.0 Head rice 36.8 31.5 77.4

Hardness (kg) 6 6 14 Chalkiness a 5 5 0 Discoloration (%) 3 5 9 Gelatinization temperature a HI/I HI/I I Cooking time (min) 25 24 24 Amylose content (%) 14.9 13.4 14.2

Milling yield (% of rough rice)

Milled rice

Complete slide sets of photos printed in Field problems of tropical rice, revised 1983, are available for purchase at $50 (less developed country price) or $60 (developed country price), including airmail postage and handling, from the Communication and Publications Department, Division R, IRRI, P. O. Box 933, Manila, Philippines. NO orders for surface mail handling will be accepted.

25.9 22.6

0.21 0.18 0.15 0.11

1.03 2.45 2.49 8.40

77.0 76.0

14 0

20 I

24 13.8

5.5 6.1 – – – –

1.46 ns 1.19 0.54

– –

a Standard evaluation system for rice.

Genetic Evaluation and Utilization DISEASE RESISTANCE

Field screening against tungro (RTV) in Lanrang, Indonesia

Table continued

Line RTV score RTV score a

Line M. Sudiak S., A. Muis, and S. Sama, Maros 4 WT 6 WT 8 WT 4 WT 6 WT 8 WT Research Institute for Food Crops, P.O. Box B6443-10-Mr-1-1-2 173, Ujung Pandang, Indonesia B6228-Mr-47-4-1

0 1 3 0 1 3 0 1 3 1 3 3 1 3 3 0 1 3 0 1 3

B6678d B5994-Mr-28-3-3-3-0 B6229-Mr-14-3-2-2 B5964-Mr-12-1-2-1 B6932-Mr-1-blk B6229-Mr-28-1-1-2 B5960-Mr-18-8-1-1-0

1 3 3 0 1 3 1 3 3 0 1 3 0 1 3 0 1 3 1 3 3

B7000-Mr-8

B7004-Mr-1 Breeding lines from the Bogor Research B5960-Mr-18-9-3-0

B6553-Mr-1-1 B6058-Mr-19-2-1-2 B6682-Mr-1-2 B6471-Mr-6-3-1 B6548-Mr-1-2 B6058-Mr-19-2-1-1

B6448-2-Mr-4-3-1 M6964-Mr-4-3-3

B6058-Mr-19-2-3-2 B6446-25-Mr-2-14 B6207e

0 0 0 0 0 0 0 0 0

1 1 1 1 1 1 1 1 1

3 3 3 3 3 3 3 3 3

B6932-Mr-10-blk

B5517f-Kn-22-0-0 B6733-Mr-7-2

B6932-Mr-11-blk B6696-Mr-14-3 B6932-Mr-25-blk B6680-Mr-9-3 B6058-Mr-19-2-1-2 B6679-Mr-23-2

1 1 3 1 1 1 1 1 1

3 3 3 3 3 3 3 3 3

0 0 1 0 0 0 0 0 0

Lines identified as resistant to RTV and their reaction at 4, 6, 8 WT at Lanrang, South Sula- wesi, Indonesia.

RTV score a

4 WT 6 WT 8 WT Line

B6240-Mr-1-3-3 0 0 0 B6228-Mr-10-1-1-2 0 0 0 B6242-Mr-23-3-1 0 0 0

a By the SES 0–9 scale.

B6236-Mr-14-1-2 B6932-Mr-26-blk B6025-Mr-56-1-3-2-0 B6209e B 6 716-Mr-4-3 B6240-Mr-1-3-2 B6680-Mr-9-6 B6346-Mr-3-2-1 B6228-Mr-10-1-1-3 B6448-2-Mr-4-3-2 B6448-2-Mr-4-3-1 B6350-Mr-6-2-1

B6229-Mr-28-1-1-1 B6208e

B6723-Mr-1-4

B6234-Mr-14-2-3-1 B6007-Mr-34-1-1-2-0 B6058-Mr-16-2-3-3 B6733-Mr-2-2

B6228-Mr-47-4-3 B6058-Mr-14-2-3-2

0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0

0 0 0 0 0 0 1 0 1 0 0 1 0 1 1 1 0 1 0 1 0 1 1 1 0 1 1 1 3 3 1 3 1 3 1 3 1 3 1 3 1 3

Institute for Food Crops (BORIF) were evaluated in the field during the 1986 monsoon season to identify sources resistant to RTV.

Each line was transplanted in 2 rows of 20 hills/row at 20- × 20-cm spacing. RTV-infected TN1 plants were transplanted in 1 row between each line.

The trial plot was fertilized at 90 kg N and 26 kg P/ha. RTV was scored by the Standard evaluation system for rice (SES) at 4, 6, and 8 wk after transplanting (WT).

resistant to RTV (see table). Of 1,500 accessions screened, 56 were

Multilocational screening for bacterial blight (BB) resistance

K. V. Patel, D. G. Vala, T. C. Patel, and S. Raman, National Agricultural Research Project, Gujarat Agricultural University, Navsari 396450, India

With increased irrigation facilities, rice has become a major food crop in Gujarat. It is grown predominantly in the south. BB (Xanthomonas campestris pv. oryzae), false smut (Ustilaginoidea virens now Claviceps oryzae), and blast

14 IRRN 12:3 (June 1987)

( Pyricularia oryzae ) are major diseases. BB inflicts heavy losses every year.

During 1984-85 kharif, we screened 103 entries for BB resistance under natural disease pressure in Navsari and Vyara. Each entry was transplanted in 2 rows, each 2.25 × 0.3 m. One row of highly susceptible GR11 was transplanted between each entry and on all sides. Fertilizer was applied at 150- 75-0 kg NPK/ha. At 40 d after transplanting, the entries were inoculated by clipping the leaf tips and spraying a bacterial suspension collected

from naturally infected leaves. Disease severity was rated on the Standard evaluation system for rice, 15 d after inoculation.

Variation in disease intensity in the two locations may be due to variation in the pathogen as well as differences in disease pressure (see table). Of the 103 entries screened, none were resistant, only 4 were moderately resistant (IRTP8160, IRTP10492, lRTP12158, and 3-8-3-3-1), and 23 scored 5 at both sites.

Genetic Evaluation and Utilization INSECT RESISTANCE

Reaction of rice varieties to the mite Oligonychus oryzae

M. Velusamy, D. Alice, and M. Subramanian, Rice Research Station (RRS), Ambasamudram, Tamil Nadu 627401, India

A sudden and severe incidence of O. oryzae occurred the first week of Sep 1986 at RRS, when maximum temperature shot up to 36 °C. Mites inhabited the underside of the rice lamina in the nursery as well as in the

main fields. Affected plants showed whitish patches on leaf surfaces; in severe cases, the leaves turned grayish white and dried up.

Severe incidence also occurred in Echinochloa colona, a wetland weed found with rice that may be an alternate host.

varieties being raised in nonrandomized observational plots (10 m 2 ) were screened for reaction to mite. The crops

Fifteen Tamil Nadu and 8 IRRI

Reaction of rice varieties to mite incidence in Tamil Nadu, India, 1986.

Variety Origin Mites/cm2 Leaf damage (%)

TM8089 Tamil Nadu 0 0 TKM9 Tamil Nadu 0 TNAU80058

0 Tamil Nadu

CO 41 0 0

Tamil Nadu ACMl0

0 0 Tamil Nadu

ACM9 0 0

Tamil Nadu AD85001

0 0 Tamil Nadu

AD9246 0 0

Tamil Nadu ADT36

0 0 Tamil Nadu

IR60 0

IRRI 0

IR30 1

IRRI 3

AD24417 1 5

Tamil Nadu 2 AD25723

5 Tamil Nadu 2

PY 3 6

Tamil Nadu IR56

3 IRRI

2

IR52 6

IRRI 15

IR64 6

IRRI 21

ADT31 6 21

IR50 6

IRRI 22

IR58 10

IRRI 24

TPS1 10 28

Tamil Nadu CO 39

15 60 Tamil Nadu

IR62 IRRI 15 60 20 100

Tamil Nadu

Screening of rice cultures against BB under natural conditions. Navsari, India, 1984-85 kharif.

Entries (no.) Entries (no.) BB score common at both

Navsari Vyara locations

1 1 3 15 19 4 5 51 54 23 7 29 29 6 9 7 1 –

– –

Total 103 103

were at the booting to heading stage. Population/cm 2 was measured by selecting 2 leaves from random hills and counting mites on a cm 2 area. For percent leaf area affected, leaves were selected from 5 random hills and affected and unaffected portions measured.

no mite incidence (see table). IRRI varieties were affected, particularly IR62.

Most of the Tamil Nadu varieties had

Resistance to whitebacked planthopper (WBPH) in Rajasthan

R.S. Tripathi and R. Pandya, Agriculture Research Station, Banswara, India

WBPH was found for the first time in Rajasthan during the 1986 wet season. The infestation began the first week of Sep, infested varieties began showing hopperburn patches in late Sep.

30 varieties from the Uniform Varietal Trial early group and 20 varieties from the advanced trial. Varieties were grown in a randomized block design at 20- × 15-cm spacing with 3 replications. Scoring according to the Standard evaluation system for rice was in the last week of Oct.

We evaluated resistance in the field of

IRRN 12:3 (June 1987) 15

Resistance of rice varieties to WBPH at Banswara, India, 1986 wet season.

Variety Cross Damage rating a Reaction b

RPW6-18 Pusa 44-33 R35-2750 RP825-28-7-1 RP25-45-1-3 BR51-46-1-0-1 IR52 RP1670-1418-2208-1585 RAU72-9-20-1-1 UPR239-151-1-1 UPR231-28-1-2 RP1898-6 HKR 101 RP2151-40-1 RP2151-21-22 RP1831-36-1-4 RP1832-23-3-4 RR5 1-1 RP2086-74-6-1 CR314-5-10 CR314-5-3 RP2240-86-84 RP2240-153-151 RP2246-72 HKP20 AR26-5-3-5 NRL-162 SKL-17-67-11 Pusa 587-2-1 RNDR88-1-1 UPR79-151 UPRS1-47 KD3-5-13 RP9263-2256-2 RP2263-2561-1 RP1686-616-1 RP2440-32-28 RP2240-142-139 RR52-1 IR18348-36-3-3 BK79 BK190 BK398 BK657 Chambal BK770

Ratna Jaya IR36

CR220-66

IR8/Siam 9

IR8JW1263 Vijaya/PTB21 Vijaya/PTB21

Nam Sagui 19/IR2071//IR206

IR5901-2/IR8

IR20/IR5-114-3

M63-83/Cauvery IR8/IR12-178 Hamsa/IR24 Ratna/YR13-89-11 Mettasanna/Rasi

– IET4141/CR98-7216 IET4141/CR98-7216 Surekha/CR147-7369 CR141-7404/Surekha ARC665O/TNl//Mudgo/PTB 33 IET5854/IET6187

– –

RP143-4/Phalguna RP143-4/Phalguna Pusa 2-21/Surekha

Paizam/IR8

W13400/W11216 Jaya mutant/Bas. 370

IR36/T21

–

–

– – –

Sona/ARC1154 Sona/ARC1154 IET3262/Dhaneswar RP143-4/Phalguna RP143-4/Phalguna CR188-10/Indira IR5657-33-2-1/IR2061-465-1-5-5

– – – – – – – – – –

7 9 4 6 5 7 5 8 4 7 5 5 5 3 4 1 2 8 9 8 9 3 5 6 4 2 6 6 2 3 6 6 4 5 7 9 7 7 9 3 6 7 5 8 4 5 6 8 9 6

S HS MR

S MR

S MR HS MR

S MR MR MR

R MR

R R

HS HS HS HS

R MR

S MR

R S S R R S S

MR MR

S HS

S S

HS R S S

MR HS MR MR

S HS HS

S

a By the Standard evaluation system for rice. b R = resistant, MR = moderately resistant, S = suscepti- ble, HS = highly susceptible.

Eight varieties scored resistant and 15 587-2-1 showed high resistance; Jaya, moderately resistant (see table). Eleven Pusa 44-33, CR314-5-3, RP1686-616-1, were highly susceptible. RP1831-36-1-4, RR52-1, and RP2086-74-6-1 were highly RP1832-23-3-4, AR26-5-3-5. and Pusa susceptible.

The International Rice Research Newsletter and the IRRI Reporter are mailed free to qualified individuals and institutions engaged in rice production and training. For further information write: IRRI, Communication and Publications Dept., Division R, P. O. Box 933, Manila, Philippines.

16 IRRN 12:3 (June 1987)

Pothana — a gall midge (GM) resistant variety for endemic areas of Andhra Pradesh

N. Kulkarni, P. P. Reddy, D. V. Rao, and G. B. Rao, Andhra Pradesh Agricultural University, Agricultural Research Station, Warangal 506007, India

Pothana (IR579/ W12708), recently released for GM endemic areas, is 90 cm tall and produces compact, dense panicles and long slender grains. The leaf margin and other plant parts are purple. It matures in 125 d during the monsoon and 135 d during the winter seasons. It is almost immune to GM attack and is tolerant of yellow stem borer.

yielded an average 4.3 t/ha. Because GM incidence is high in the monsoon crop, the yield advantage in this season is spectacular. Among 64 varieties tested at 21 locations in 1981, Pothana ranked second with a grain yield of 4 t/ha.

In trials from 1982 to 1984, Pothana

Evaluation for brown planthopper (BPH) resistance

N. K. Dhal and S. K. Panda. Regional Research Institute, Orissa University of Agriculture and Technology, Chiplima, Sambalpur 768026, India

We evaluated field resistance to BPH of 13 cultivars, including Jaya and Ratna

Field resistance of rice varieties to BPH in Cuttack, Orissa, India, 1983.

BPH Days to

at 90 DT flowering Variety no./hill 50%

OR131-13-13 IR13429-196-1-20 IR36 OR131-11 CR157-22-1900 IR1342-108-2-2-3 OR158-13-1 OR131-3-1 OR136-3 Ratna Jaya ORl31-3-3 IR19661-364-1-2-3

11.4 86 4.9 19.6 82 4.2 63.1 87 4.2

7.7 96 4.0 32.9 91 4.0 32.2 85 3.9

197.5 88 3.4 8.9 100 3.3

16.5 99 2.9 217.6 82 2.6 112.3 98 2.6

9.7 98 2.4 9.4 96 2.0

Yield (t/ha)

Modified seedbox screening test to identify field resistance to brown planthopper (BPH)

F.G. Medrano and E.A. Heinrichs, Entomology Department, IRRI; S. Alam and M.S. Alam, Bangladesh Rice Research Institute; Y.Y. Jackson, Brewer, Solomon

as susceptible checks, in the summer season in the Adaptive Research Centre, Barachana, Cuttack. Three-week-old seedlings were planted in 20-m 2 plots at 15- × 10-cm spacing in a randomized block design with 3 replications. The BPH population was sampled from 20 hills/plot at 15-d intervals, starting from 45 d after transplanting (DT).

The BPH population did not exceed 8 individuals/hill until 60 DT; at 90 DT susceptible Ratna and Jaya had 218 and 112 BPH/hill. OR158-13-1 was highly susceptible with 198 BPH/hill. OR131- 11 and OR131-13-13 had only 7.7 and 11.3 BPH/hill and yielded more than 4 t/ha (see table).

New sources of resistance to gall midge (GM) and yellow stem borer (YSB)

N. Kulkarni, G.V.S.P. Rao, and T. Narsaiah, Andhra Pradesh Agricultural University, Agricultural Research Station, Warangal 506007, India

GM and YSB are serious pests of rice in the Northern Telangana region of Andhra Pradesh in both monsoon and winter seasons. We screened 97 varieties for resistance to natural infestations of YSB and GM.

Entries were planted in single 3-m- long rows; each row had 20 plants. GM incidence was recorded 50 d after transplanting; whitehead damage caused by YSB was recorded at harvest.

IET8340, IET8637, IET8797, RP1579-36-33, RP2091-272-3-4-8,

Moirangpheu, Aganni, and W1263 had less than 5% GM and YSB damage.

RP2091-272-8-2-7, RP2434-24-1-2,

Screening for resistance to yellow stem borer (YSB)

N. Kulkarni, G.V.S.P. Rao, and T. Narsaiah, Andhra Pradesh Agricultural University, Agricultural Research Station, Warangal 506007, India

We screened 24 varieties for YSB resistance under natural infestation during 1984 kharif. Two 30-d-old

seedlings were transplanted/hill with 20- 115-2, ARC62 15, and Manoharsali × 15-cm spacing in 3-m-long rows. TN1 scored resistant (0-5% deadhearts). was the susceptible check. Deadheart RP2199-162-2 was moderately resistant damage on 20 hills of each variety was (5.1-10% deadhearts). Other entries were recorded at 50 d after transplanting. susceptible (10.1-25% deadhearts) or

ARC5500, ARC6588, CO 18, highly susceptible (more than 25% RYT2908, W1263, ASD7, T7, RP2199- deadhearts).

Screening rice cultivars against rice whorl maggot (RWM)

M. Velusamy, D. Alice, and M. Subramanian, Rice Research Station, Ambasamudram, Tamil Nadu, India

We screened 21 varieties against RWM Hydrellia sasakii in the 1986 multilocation trial. The experiment was laid out in a randomized block design with three replications. The cross plot size was 8.325 m 2 .

Seedlings were planted 15 cm between rows and 10 cm within rows. Affected leaves and unaffected leaves were counted from 5 random hills/plot.

At 25 d after transplanting, damage was 22-57% (see table). IR64 had 57% damage. Nineteen entries, with more than 25% damage, were considered highly susceptible. Only IR28128-45-2 and TNAUBPHR831293, with 25 and 22% damage, were classified moderately resistant.

Varieties highly susceptible and moderately resistant to RWM. Ambasamudram, Tamil Nadu, 1986.

Leaf

(%) Variety Cross combination damage

IR64 ACM5 IR62 TKM9 ACM12 ACM11 ET7254 TNAUBPHR831305

ASD16 TNAU83152 KT7987 IET7988 TNAU831520

BG367-4 (AD 85003)

ADT36 ACM9 TNAUBPHR831305 AS28883 AS25370

IR28128-45-2 TNAUBPHR831293

Highly susceptible IR5657-33-2-1/IR2061-465-1-5-5 Jhona 349/IR28 ITB33/IR30/IR36 TM7/IR8

Manila/IR8 Triveni/CO 39 T7/1R8

ADT31/CO 39 PV2/IR36 M63-83/Sarya N22/IR36 PY2/IR36 Triveni/IR20 Selection from IR50 T7/IR8 TKM9/IR36 ASDl/IRON297

–

BG280-1*2/PTB33

Moderately resistant IR36/IRlO154-23-3-3//IR9129-209-2-2-2-1 T7/IR20

57.3 56.6 52.2 52.1 51.7 50.7 50.0 50.0 45.5 43.9 42.0 39.7 38.8 34.8 36 .0 33.3 33.3 31.3 29.5

25.0 22.2

Islands; and D. Senadhira and N. Wickramasinghe, CARI, Sri Lanka

In field screening for resistance to BPH - at IRRI, some varieties are resistant in the field but susceptible at early seedling stage in the greenhouse. We modified the standard seedbox screening test

IRRN 12:3 (June 1987) 17

BPH damage ratings of selected rice varieties in 4 countries in the standard and the modified seedbox screening tests.

Damage rating a

IRRI Variety

Biotype 1 Biotype 2 Biotype 3 Bangladesh Solomon Islands Sri Lanka

SSST MSST SSST MSST SSST MSST SSST MSST SSST MSST SSST MSST

Sinna Sivappu 1.5 a 1.0 a 1.5 a 1.5 a 1.0 a 1.5 a 1.0 a 1.0 a 1.0 a Kencana

1.0 a 6.5 bc 2.5 ab 6.0 c 1.5 a 6.0 bcd 3.0 ab 9.0 c 9.0 c 7.8 bc 6.8 de 7.5 bc 6.0 a

5.5 a 6.0 a

IR26 3.0 a IR46

2.5 ab 8.5 d 8.5 c 3.5 ab 4.0 ab 8.0 c 5.0 b 8.8 c 7.0 e 7.0 ab 8.0 b 1.5 a

ASD7 1.5 ab 8.0 d 1.5 a 4.0 bc 3.5 ab 6.0 b 5.0 b 7.0 b 1.0 a 3.5 b

3.0 b 7.5 bc 8.0 b 2.0 a 1.5 a 8.5 d 8.5 c 9.0 c 9.0 c 7.5 bc 5.5 c 8.0 bc 8.5 b

Utri Rajapan 6.0 b 2.0 ab 7.5 cd 1.0 a 6.5 cd 4.5 ab 9.0 c 6.0 c 9.0 c 6.0 cd 7.5 bc 5.0 a Triveni TN 1

8.0 cd 3.0 b 8.5 d 5.0 b 7.5 d 6.5 bc 9.0 c 6.0 c 8.0 bc 7.2 e 7.0 ab 5.5 a 9.0 d 9.0 c 9.0 d 9.0 c 8.0 d 9.0 c 9.0 c 9.0 c 9.0 c 9.0 f 9.0 c 8.5 b

a By the SES scale 0–9: 0 = no damage, 9 = plants killed. In a column, means followed by a common letter are not significantly different at the 5% level by Duncan’s multiple range test.

(SSST) to identify field-resistant varieties in the greenhouse. Varieties in which resistance is expressed in older plants are useful because their resistance may be stable and not easily broken down by the selection of virulent biotypes.

The feeding behavior of the South Asia BPH population differs from that of Southeast Asia BPH. Some varieties that are resistant in Southeast Asia are not resistant in South Asia and vice versa. A collaborative project compared the SSST and the modified standard seedbox screening test (MSST) in tests conducted in the Philippines, Bangladesh, Solomon Islands, and Sri Lanka. Seeds of eight varieties and methods for conducting the tests were sent from IRRI. Varieties were selected on the basis of their reactions in SSST and in IRRI fields.

Sinna Sivappu was the resistant (R) check, TN1 was the susceptible (S) check. IR26 was selected as the basis for testing IR46. IR26 is S to biotype 2 in the SSST and in the field; IR46 is S in the SSST but R in the field. ASD7 is a R check for biotypes 1 and 2 and a S check for biotype 3. Kencana, Utri Rajapan, and Triveni are S in the SSST, but moderately R to R in the field.

Test insects were reared on 60- to 80- d-old TNI plants except for biotypes 2 and 3, which were reared on Mudgo and ASD7 at IRRI.

In the commonly used SSST, 25 seeds of each variety are sown in a 60- × 45- × 7-cm seedbox in 20-cm rows with

5-cm spacing between rows. Varieties are arranged in a randomized complete block design with one row of each variety replicated four times. At 7 d after sowing (DAS), each seedling is infested with 8 to 10 2d- or 3d-instar nymphs. When plants in the S TN1 check are killed, damage is scored by the Standard evaluation system for rice (SES).

The design and methods used for MSST are the same as for SSST except that each seedling was infested at 10 DAS with 3 to 5 2d- or 3d-instar nymphs. The F1 progeny of the initially infested insects killed the S check about 28 d after initial infestation.

Kencana was moderately susceptible (MS) or S to all three biotypes in the SSST in all countries, but R in the MSST at IRRI (see table). IR46 and IR26, with the same major resistance gene (Bph 1), had similar reactions in the SSST at all locations. In the MSST, however, IR46 was R to biotype 2 and

the Solomon Islands population, IR26 was S. In IRRI field tests, IR46 was R to biotype 2.

Utri Rajapan and Triveni had lower damage ratings in the MSST than in the SSST at all locations. At IRRI, Utri Rajapan had a rating of 7.5 in the SSST and 1 in the MSST for biotype 2. It becomes tolerant of biotype 2 after the seedling stage in both greenhouse and field tests.

Only Utri Rajapan and Triveni showed field resistance across all locations. The lack of uniformity in Kencana and IR46 may be due to a lack of field resistance to certain populations or to some variation in the methodology used.

Utri Rajapan is being used as a donor of field resistance to BPH in breeding programs at IRRI. It also has a high tolerance for BPH and whitebacked planthopper and is resistant to rice tungro virus.

Genetic Evaluation and Utilization COLD TOLERANCE

Variability in yield and yield and early Aug often damage the seedbed components of normal and late- or newly transplanted seedlings. sown rice in West Bengal Farmers have to prepare fresh seedbed.

When floodwater recedes, new seedbeds S. K. B. Roy, State Agricultural E2xperimental cause late transplanting in the main Station, Malda, West Bengal, India field.

Stagnant rainwater or flash floods in Jul times are needed to replace traditional Varieties adapted to different sowing

18 IRRN 12:3 (June 1987)

Variability in yield and yield components under normal and late sowings. Malda, West Bengal, India, 1985-86.

Duration Plant Panicle Tillers Grains/ 1000- Yield Sterility Sowing date Line (d) height length (no.) panicle grain (t/ha) (%)

(cm) (cm) wt (g)

13 Jul CN657-21 106 161 21 8 120 28 2.5 19 CN671-28 111 149 24 7 173 25 2.8 18 CN671-29 102 131 23 10 145 30 2.6 20

Mean 106 147 23 8 146 27.6 2.6 19

19

24 Mean 93 119 23 11 117 28.6 1.6 22 % reduction 12.3 19.0 0.0 –37.5 19.8 –3.6 38.46

F value a Variety (V) 180.4** 81.05** 0.07 ns 6.83** 130.5** 34.4** 0.84 ns Sowing (S) 635.2** 39.23** 0.014 ns 12.61** 303.6** 9.4** 6.55**

10 Aug CN657-21 92 137 23 11 122 29 1.5 CN671-28 101 121 23 9 127 28 1.5 23 CN671-29 87 98 22 13 103 29 1.8

V × S 11.9** 1.3 ns 0.019 ns 0.46 ns 95.72** 19.1** 0.34 ns a ** = significant at the 1% level.

varieties.

two environmental factors that can reduce yield: a gradual decline in average night/day temperatures and drought during the reproductive stage. The effects are pronounced in northern West Bengal.

We conducted an experiment in the old Gangetic alluvium region at Malda (25°33'N) to identify important characters for late sowing and to evaluate the effect of temperature on the reproductive stage.

Late-planted rice generally encounters Three advanced lines derived from

CNL 231/Pankaj and Pankalash/CRI006 crosses were sown on 13 Jul and 10 Aug. The 30-d-old seedlings were transplanted 20 × 15 cm apart in 5-m 2 plots with 5 replications. Fertilizer was applied 60-30-30 kg NPK/ha.

In the variability study, heading duration, total grains/panicle, and 1,000-grain weight significantly differed among varieties and by sowing date, and variety × sowing interaction (see table). Although plant height, filled

grains/panicle, and yield were reduced by 19, 19.8, and 38.5% in late sown rices, effective tiller numbers and 1,000- grain weight increased.

Days to heading was 102-1 11 in the Jul-sown crop and 87-101 in the Aug- sown crop. Average temperature was 26.5 °C during panicle initiation for Jul and 23.3 °C for Aug sowings. Average temperatures of 22 °C and 20 °C prevailed during grain filling.

Although low temperatures were not critical for mid-Aug sowing, sterility % was higher with late sowing.

Genetic Evaluation and Utilization DROUGHT TOLERANCE

Drought tolerance of some rice hybrids and their parents

D. K. Sharma, M. N. Shrivastava, P.S. Shrivastava, and A.S.R.A.S. Sastry, Zonal Agricultural Research Station, J. N. Krishi Vishwa Vidyalaya, College of Agriculture, Raipur 492012, M. P., India

In several crop plants, hybrids have shown higher drought tolerance than their parents. This has been attributed to deeper and more developed root systems. Under such situations as midseason rain failures in rainfed rice, this capacity could make the difference between a relatively good crop and a total failure.

We evaluated 11 rice hybrids and their parents for drought tolerance in a split-plot design in 2 replications using 15 plants each during the 1984 dry season. Irrigation treatments were in main plots and the hybrids and their parents in subplots. Irrigation was withheld for 14 d at late tillering or panicle initiation. Plots were normally irrigated afterwards. The mean values and percent reduction of four traits under normal irrigation and under drought stress are presented in the table.

Grain yield reduction in five hybrids was less than in the lesser affected parent. In another five hybrids, it was between the two parents. Only one hybrid had higher yield reduction than

both parents, probably because this hybrid flowered in late May and was affected by hot winds.

Among the parents, Taichung Senyu 285 had exceptionally high tolerance for drought, with higher yield under stress than all the other hybrids. None of the correlation coefficients between characters were significant.

Individuals, organizations, and media are invited to quote or reprint articles or excerpts from articles in the IRRN.

IRRN 12:3 (June 1987) 19

Grain yield reduction and some yield components of hybrids and their parents under irrigated and drought conditions. Raipur, India, 1984 dry season.

Plant height Effective tillers Filled grains/panicle Grain yield/plant Entry Situation a

Mean Reduction Mean Reduction Mean Reduction Mean Reduction (cm) (%) (no.) (%) (no .) (%) (g) (%)

BG367-4/MW10

IR25571-31/MW10

MW10/Samridhi

IR36/Azucena

IR9752-71/Ratna

Taichung Senyu 285/Samridhi

Taichung Senyu 285/MW10

RP1140-27/Ratna

IR13240-82/IR36

IR25571-31/Poorva

Taichung Senyu 285/Poorva

N D N D N D N D N D N D N D N D N D N D N D

MWl0 N D

BG367-4 N D

IR25571-31 N D

Samridhi N D

IR36 N D

Azucena N D

IR9752-71 N D

Ratna N D

Taichung Senyu 285 N D

Poorva N D

RP1140-27 N D

IR13240-32 N D

LSD (0.05) Main plot means Subplot means Subplots at same main plot level

7 2.4 60.2 61.0 60.0 74.0 56.4 60.0 52.6 60.0 54.4 12.4 57.2 75 .0 58.7 60.6 50.5 75.0 65.1 77.7 61.5 65.0 54.3 71.2 58.4 72.2 56.1 7 3.4 62.6 76.6 55.2 72.0 55.1 62.3 54.3 60.4 56.1 74.0 60.8 66.2 53.4 67.8 62.3 68.2 57.8 63.2 47.4

0.4 2.3 3.3

16.8

1.6

23.8

12.3

9.3

21.0

21.7

17.0

13.2

13.1

16.5

17.7

22.3

14.7

27.9

23.5

12.8

7.1

17.8

19.3

8.1

15.2

25.0

15.2 14.1 15 .0 10.0 13.6 13.4 13.3 12.7 10.0

7.2 15.5 15.2 16.3 16.0 15.3 12.2 14.3 12.3 11.2 10.1 15.0 11.1 12.0 10.9 12.0 11.3 17 .0 12.4 19.0 13.8 19.0 15.9

7.0 5.8

23.0 16.3 16.0 13.7 17 .0 15.5 21.0 13.8 16.0 12.0 25 .0 19.5

0.5 1.7 2.4

7.2

33.3

1.5

4.5

28.0

1.9

1.8

20.3

14.0

9.8

26.0

9.2

5.8

27.1

27.4

16.3

17.1

29.1

14.4

8.8

34.3

25.0

22.0

63.6 48.7 77.3 61.0 74.0 35.3 94.0 62.9 60.4 46.4 73.0 66.8 75.0 35.8 70.3 59.4 71.5 29.2 77.8 59.8 69.0 29.7 77.2 70.2 75.0 24.0 73.4 39.2 76.6 44.3 72.0 41.2 62.3 41.8 60.4 27.6 74.0 52.0 66.2 32.8 75.6 62.6 69.0 39.1 69.0 39.1

2.5 2.8 3.9

23.4

21.1

52.3

33.1

23.2

8.5

52.2

15.5

59.2

23.1

56.9

9.1

68.0

45.6

42.2

42.8

32.9

54.3

29.7

50.0

17.2

43.3

43.3

15.2 14.1 15.0 12.9 13.6 12.3 13.3 11.4 11.0

9.6 15.5 13.0 16.2 15.5 18.5 16.0 14.5

8.3 16.0 11.8 15.0

9.3 16.6 13.2

9.4 7.7

13.8 9.4

18.4 7.7

13.6 5.8 9.7 7.9

17.6 12.2 16.2

8.9 18.6 17.9 19.2 16.4 13.2 12.1 19.2 12.9

0.8 1.3 1.8

7.2

14.0

9.6

14.3

12.7

16.1

4.3

13.5

42.7

26.3

38.0

20.5

24.5

31.9

58.1

57.3

18.6

30.7

45.1

3.8

14.6

8.3

32.8

a N = normal, D = drought.

The International Rice Research Newsletter (IRRN) invites all scientists to contribute concise summaries of significant rice research for publication. Contributions should be limited to one or two pages and no more than two short tables, figures, or photographs. Contributions are subject to editing and abridgment to meet space limitations. Authors will be identified by name, title, and research organization.

20 IRRN 12:3 (June 1987)

Genetic Evaluation and Utilization ADVERSE SOILS TOLERANCE

Field screening of hybrids for the second crop in acid sulfate soils of South China

K. Tan and Jinpei Li, Research Laboratory of Tropic and Subtropic Soils, South China Agricultural University, Guangzhou, China

We screened acid-tolerant hybrids for the second crop in acid sulfate soils (Table 1) of Duanfen and Wencun, Taishan County, Guangdong Province, in 1985.

At Duanfen, 18 varieties were tested

Table 1. Characteristics of the acid sulfate soils in Duanfen and Wencun, South China, 1985.

Location

Duanfen Wencun Item

pH (H 2 O) 3.85 3.71 pH (KCl) 3.17 3.23 Total N (%) 0.22 0.17 Organic C (%) 3.13 2.16 Available P (Olsen, ppm) 1.6 4.4 Exchangeable K 0.29 0.45

Available Zn (ppm) 7.8 8.1

Water soluble SO 4 0.44 1.28

Active Fe (%) 2.70 2.49 Active Mn (ppm) 20.1 19.5 Particle size (%)

Sand (2-0.005 mm) 6.6 22.7 Silt (0.05-0.001 mm) 62.9 58.2 Clay (<0.001 mm) 30.4 19.1

(meq/100 g)

(0.05 N HCl)

(meq/100 g)

under 2 fertilizer treatments: with (1.6 t CaO/ha) and without. Limed or not, Shanyou 63 yielded best, followed by Qingyouzao, Ganghuaqinglan Fo, and Shanyou 36 without liming (Table 2). Because early high rainfall might have decreased soil acidity, only some varieties showed slight Fe toxicity in the late growth stage and the difference between the fertilizer treatments was not significant. In general, most hybrids

tested adapted to the soil.

screened with NPK fertilizers. The varieties suffered more severe Fe toxicity in late growth stage. Many grains on panicles were empty in 21 varieties (Table 3).

The yield variation in Wencun was affected by percentage filled spikelets rather than straw weight, panicle numbers, and grains/panicle.

In Wencun, 31 rice varieties were

Table 2. Grain yield of second crop of rice screened in acid sulfate soil at Duanfen, South China, 1985.

Grain yield Tested rice

Without liming With liming Variety Type a

kg/plot Rank kg/plot Rank

Shanyou 63 HV 1.00 1 1.04 1 Qingyouzao HV 0.98 2 0.82 4 Ganghuaqinglan Fo HV 0.95 3 0.81 5 Shanyou 36 HV 0.93 4 0.87 3 Shanyou 2 HV 0.89 5 0.77 8 Shanyouxuan 30 HV 0.89 5 0.93 2 Ce 64 RV 0.85 6 0.67 10 Qiuzhongai RV 0.81 7 0.67 10 Zhubao 384 RV 0.76 8 0.82 4 Shanyou 64 HV 0.73 9 0.79 7

Wanhuaai 1 RV 0.72 10 0.75 9 Qinghuaai 6 RV 0.72 10 0.77 8 Gangbaiai RV 0.71 11 0.65 11 Qinghuaai RV 0.68 12 0 .80 6 Guishanai RV 0.66 13 0.62 13 Liuyou 2 HV 0.66 13 0.61 14 Xiangaizao 9 RV 0.33 14 0.30 15 a HV = hybrid variety, RV = regular variety.

V-you 35 HV 0.72 10 0.63 12

Table 3. Field screening of second crop rice in acid sulfate soil at Wencun, South China, 1985.

Tested rice Growth Dry Av Grains/ Ripe Filled Grain Grain period straw wt panicles/ panicle state spikelets yield yield

Variety Type a (d) (kg/plot) plant (%) (kg/plot) rank

Chanjiang 204 RV 147 2.87 10.5 95.4 Better 68.0 2.01 1 Qinghuaai 6 RV 141 2.05 8.4 91.6 Better 67.3 1.80 2 Ganghuaqinglan Fo HV 141 1.74 10.0 80.1 Better 62.3 1.75 3 Ciuzhongai RV 141 1.75 8.1 123.0 Better 67.0 1.60 4 Zhubao 384 RV 139 2.07 8.8 75.3 Better 77.9 1.54 5 IR54 IV 138 2.65 9.2 85.9 General 53.7 1.36 6

IR46 IV 139 2.82 8.9 106.5 General 52.4 1.16 8 Gangbaiai RV 137 2.03 10.5 72.8 General 50.3 1.10 9

Shanyou 35 HV 131 1.87 11.6 76.2 GWFR b 27.6 0.83 11

IR4422-480-2-3-3 IV 139 2.88 7.6 86.8 General 46.2 1.20 7

IR32307-107-3-2-2 IV 134 1.97 10.7 101.9 General 41.2 1.07 10

IR28228-119-2 IV 143 3.02 11.1 107.7 GWFR 14.9 0.81 12

Continued on next page

IRRN 12:3 (June 1987) 21

-

Table continued

Tested rice Growth Dry Av period straw wt panicles/ Grains/ Ripe Filled Grain Grain

Variety Type a (d) (kg/plot) plant panicle state spikelets yield (%)

yield

IR36 IV 134 1.50 10.5 V-you 35 HV

62.6 GWFR 133

8.1 1.75 10.4 59.6

0.71 GWFR

13

IR42 IV 143 8.2 103.6 25.7

3.17 0.67 14

Wanhuaai 1 RV 141 81.0 GWFR GWFR

2.00 25.0

7.7 0.58 15

Shanyou 64 HV 132 2.66 10.3 63.5 GWFR 43.7 0.5 3 16

Xiangaizao 9 RV 134 1.52 7.7 0.51

14.5 40.2 GWFR 17

Shanyou 36 HV 131 2.62 11.1 59.4 14.4 0.45

GWFR 18

Guo 16 RV 138 2.41 9.8 104.0 GWFR 4.2 0.35 19

Shanyou 63 HV 133 9.7 75.5 GWFR 16.0

2.41 0.33 20

Yuachi 231-8 RV 136 2.57 15.0 56.6 GWFR 11.7 0.31 21

0.5 2.71

0.24 13.0

22

IR50 IV 132 2.96 57.2 GWFR 2.1 0.21

14.6 23

Liuyou 2 HV 133 60.5 GWFR

2.86 7.8 7.4 0.19 24

Ce 64 60.1

RV 133 2.87 8.7 GWFR 16.0 0.19

87.6 GWFR 24

IR58 IV 132 2.58 79.3 GWFR 12.9

8.1 0.18 25

IR29725-22-3-3-3 IV 132 2.67 11.0 0.4 0.14 26

IR9764-45-2-2 IV 57.0 GWFR 2.5 0.08 27

IR13145-45-2-3 IV 145 IR25587-133-3-2-2-2 IV 145 --- ---

(kg/plot) rank

IR131427-60-1-3-2-2 IV 132

145 --- --- --- GWFR --- --- --- GWFR GWFR

--- --- --- --- --- ---

--- --- --- ---

a IV = IRRI variety. b Green without full ripeness.

Genetic Evaluation and Utilization HYBRID RICE

Early-maturing hybrid rice date by the end of Jul. Morphological characters, seed combinations Wei You 35 is a high-yielding

combination developed in 1980. Xie setting, and dry matter production

Qing Zao A/Xuan 10-19 had the of A and B lines

Mao Chang-Xiang, Hunan Hybrid Rice Research Center, Changsha, China

Ten newly developed early-maturing hybrid rice combinations were tested in a six-location yield trial in the first cropping season 1986 in Hunan Province. Plot size was 13.3 m 2 in 3 replications. Sowing was from the end of Mar to early Apr with harvesting

significantly highest yield (see table). It is moderately resistant to bacterial blight and blast. L301 A/R29, with good grain quality, was selected in Texas, USA, by Chinese scientists. Its yield is not significantly lower than that of Wei You 35. Xie Qing Zao A/Xuan 10-19 and L301 A/R29 were developed by the Hunan Hybrid Rice Research Center.

Growth duration and yield of newly developed early-maturing rice hybrids. Hunan, China, 1986.

M. Rangaswamy, S.R.S. Rangasamy, K. Natarajamoorthy, and V. Sivasubramanian, School of Genetics, Tamil Nadu Agricultural University (TNAU), Coimbatore 641003, India

Morphological characters, seed set percentage, root to straw ratio, and dry matter production were estimated in 11 cytosterile lines of rice (A) and their maintainers (B). Five are from China, four from IRRI, and two from TNAU.

The cytosteriles were high in total dry

over check (kg) distributed in root and straw (see table).

Growth Combination duration

(d)

Yield Increase

(t/ha) (%) Yie1d/d matter production, predominantly per ha

Xie Qing Zao A/Xuan 10-19 118.8 7.9 7.66 a 66.8 L301 A/R29 Xie Qing Zao A/S 5 -200 119.6 7.0 –4.44 59.0 were taller, but panicle length was V 20 A/H 78 121.6 7.0 –5.17 57.6 Wei You 26 117.0 6.8 –7.76* V 20 A/383

58.1 117.8 6.8 –7.90* 51.8 The increased weight of vegetative

Z 97 A/To 326 118.8 6.8 –8.14* 57.0 parts in A lines may be due to the V 20 A/305 119.0 6.7 –9.69* V 20 A/S 5 -990 115.0 Chang 22 A/T 65 Wei You 35 (check) 120.6 7.4 61.2 however, were not utilized by the

In general, root:straw was higher in A 117.4 7.2 –2.37 61.4 lines than in B lines. Plants of B lines

greater in A lines.

56.0 mobilization of nutrients to tillers and 56.7 the prolonged vegetative phase. These, 6.5 –11.57**

126.6 5.5 –24.85** 43.8

a Significant at the 5% (*) and 1% (**) levels. reproductive parts because of poor sink

22 IRRN 12:3 (June 1987)

Characters of A and B lines. TNAU, India.

Plant ht Panicle length Panicle Tillers Root length Straw dry wt Root dry Root to Grain setting Line (cm) (cm) exsertion a (no.) (cm) (g) wt (g) straw ratio (%)

A B A B B A B A B A B A B A B A B (cm)

V20 64 66 19.9 18.0 1.52 8 6 13.6 12.2 5.8 4.1 4.7 2.5 1.23 1.64 19.5 80.9 Zhen-shan 97 57 73 20.8 19.6 1.54 19 6 18.6 17.2 12.5 4.3 6.0 2.5 2.08 1.72 13.5 79.8 Er-jiu-Nan 1 63 65 18.8 17.3 1.64 20 8 18.0 17.0 14.5 4.5 8.5 3.0 1.71 1.50 11.0 88.6 Yar-ai-Zhao 1 67 68 18.5 19.3 1.66 17 9 14.0 14.8 8.5 7.5 7.5 5.0 1.13 1.50 16.2 68.5 Yar-ai-Zhao 2 70 78 22.5 21.2 1.68 15 6 10.6 11.6 8.3 6.1 5.5 4.7 1.51 1.30 9.6 74.7 IR46827 62 69 19.9 17.9 1.61 24 18 17.8 19.3 17.8 5.0 8.5 3.5 2.09 1.43 14.3 77.2 IR46828 62 74 22.1 19.8 1.62 19 13 17.7 15.1 17.5 5.2 7.0 3.3 2.50 1.56 7.5 77.9 IR46829 58 67 20.0 18.1 1.58 11 7 14.5 16.3 16.5 4.8 6.0 4.0 2.75 1.20 11.5 81.8 IR46830 58 63 21.4 18.5 1.60 21 8 18.2 17.1 15.3 4.6 7.7 4.0 1.99 1.15 17.6 76.6 TNMS31 90 96 22.0 21.5 1.65 17 10 14.7 14.2 16.6 11.5 9.2 8.5 1.80 1.35 9.5 85.9 TNMS37 82 93 22.1 22.9 1.74 15 9 18.9 17.2 18.3 9.0 8.0 6.5 2.29 1.38 17.9 87.9

Mean 67 74 20.7 19.5 1.62 17 9 16.1 15.6 13.8 6.1 7.2 4.3 1.92 1.43 13.5 80.0 CD (0.05) 16 21 2.3 2.6 ns 6 5 3.2 2.5 5.2 2.6 2.1 1.8 0.48 ns 3.4 12.4

a Values were zero for A.

size reflected by spikelet sterility. The boot leaf. Poor panicle exsertion in the interaction between nonrestorer gene reduction in height of A lines may be male sterile lines may be associated with and sterile cytoplasm. due to lack of panicle exsertion from the a nonrestorer gene or it may be due to

Performance of three new hybrid rices Xie Fangming, Hunan Hybrid Rice Research Center, Changsha, Hunan, China

We evaluated the yield potential and grain quality of three new hybrid rices in Changsha in May-Sep 1986. Seeds were sown 14 May; 30-d-old seedlings were transplanted at 2 seedlings/ hill and 20-× l5-cm spacing in a randomized block design with 3 replications.

expected to be released commercially (see table). Although its yield was not significantly higher than that of Shan You 63, a widely grown hybrid in south and southwest China, its seed production is considerably higher because the cytoplasmic male sterile (cms) line II-32 A possesses such floral traits as large stigma, good panicle, and stigma exsertion, suitable for a higher natural outcrossing rate.

The cms lines used in the new hybrids possess a cms system different from that of WA types. Tian-Ai A is gametophytic, others are sporophytic. MH63, the R line used in the four combinations, was derived from a strain of Gui 630/ IR30.

Lodging caused some yield loss due to heavy rain during grain ripening.

II-32 A/ MH63 performed well and is

Performance of new hybrid rices in yield trials in Changsha, China, 1986.

Character 11-32 A/ Tian Ai A/ Guang-Tan 69 A/ Shan You 63 MH63 MH63 MH63 (check)

Plant height (cm) 119 119 123 117 Growth duration (d) 137 132 133 129 Panicles (no./m 2 ) 296 342 320 311 Filled spikelets (no./panicle) 12 2 93 97 106 1000-grain wt (g) 27.2 27.6 25.5 Yield (t/ha) Brown rice yield (%) 79.7 78.7 80.4

length (mm) 6.5 6.7 6.6 width (%) 2.6 2.5 2.4 length: width 2.5 2.7 2.8

Total milling yield (%) 75.7 72.7 73.8 Head rice (%) 33.6 62.5 41.0 Chalky rice a (%) 15.5 32.0 27.0 Chalky area of milled rice a (%) 1.8 2.3 4.3 Gel consistency (mm) 27 35 38.5 Alkali spreading value (scale) 6.7 5.6 6.5 Amylose content (%) 20.3 21.2 21.1

a Based on the weight of rough rice.

29.3 8.5 7.8 7.4 8.3

Genetic Evaluation and Utilization TISSUE CULTURE

A simple device for mass extraction Inoculating several thousand anthers is of rice anthers

S. K. Raina and S. Hadi, Biotechnology desirable type(s). Because their flowering Centre, Indian Agricultural Research duration is short, several F 1 hybrids or Institute, New Delhi 110012, India other material may have to be utilized

Anther culture techniques for use in anthers becomes a cumbersome and breeding generally show low efficiency. labor-intensive job.

necessary to generate a pollen-plants population large enough for selecting

within a short period. Isolation of

IRRN 12:3 (June 1987) 23

Procedure for mass extraction of anthers from rice florets. All operations are carried out under aseptic conditions and, therefore, all the neces- sary instruments, glassware, etc. are sterilized.

These limitations restrict the quantity of anther culturing possible and have often been criticized as impractical.

We have evolved a simple device for mass extraction of anthers (see figure). We used an animal cage feeding bottle (125 ml capacity) made of polypropylene or polymethylpentane and fitted a 3.5-cm length of steel tubing into the screw cap of the bottle. From the bottom to about 3/4 up the bottle, horizontal slits about 1.5 mm wide and 3 cm long are made 4 mm apart in 4 vertical rows. Slits of one row correspond to the gaps of the adjacent row.

When florets are stirred in the bottle, the slits allow the anthers to pass through, leaving empty glumes behind. After each lot of florets, the debris can

24 IRRN 12:3 (June 1987)

be removed and the device rinsed with isolated in less than 50% of the time sterile distilled water. needed in conventional methods.

over 80% and found that anthers can be autoclavable, and reusable. We have recorded anther yields of The device is resistant to breakage,

Pest Control and Management DISEASES

Leaf blast (BI) season rice

outbreak in dry dry season rice in the Hirakud command areas of Western Orissa. Leaf Bl appeared for the first time in the 1982

N.K. Dhal, S.S. Nanda, S.S. Mishra, and dry season and was severe in 1986. B. Mishra, Regional Research Station We surveyed disease incidence and (RRS), Chiplima 768026, India found that popular varieties Daya,

Bl caused by Pyricularia oryzae, known with disease intensities ranging from to be endemic in the hilly tracts of 41.2 to 82.9%. However, IR36 and Orissa during wet seasons, has invaded Pratap were resistant. Disease intensity

IR50, and ORS26-2014-4 were affected,

was higher at higher N levels. In a trial at RRS, Chiplima, Daya

was grown in randomized block design plots with four replications. N levels were 0, 40, 80, 120, and 160 kg/ ha. Leaf B1 appeared at maximum tillering during the second wk of Mar, when night temperatures were as low as 15.5– 19.5 °C, day temperatures as high as 32.5–36 °C, accompanied by high morning relative humidity of 91.0–96.5. All fully emerged leaves of 20 random1y

Effect of N level on leaf B1 intensity and rice yield. Orissa, India.

level intensity a (t/ha)

(kg/ha) (%)

N Disease

0 27.19 (31.39) 2.9 40 47.13 (43.35) 3.9 80 60.87 (51.30)

120 3.1

160 68.43 (55.82) 2.2 67.54 (55.60) 2.7

CD (0.05) 7.58 ns CV (%) 11.43 25.5

a Figures in the parentheses are angular trans- formation values.

Purification and serology of ragged stunt virus (RSV)

A. Parejarearn and H. Hibino, IRRI

RSV was purified from RSV-infected TN1 plants (Omura procedure with some modifications). Plants with roots were homogenized with 0.1 M phosphate buffer (pH 7.0) in 0.01 M MgC1 2 . Sap clarified by freezing overnight and defrosting at room temperature was treated with 1% Triton X-100 for 30 min. Virus precipitated with 6% PEG 6000 and 0.3 M sodium chloride was suspended in 0.1 M histidine buffer in 0.01 M MgC1 2 (pH 7.0).

The suspension was treated with 20% CCl 4 and differentially centrifuged. The virus fraction was layered on 20–50% linear sucrose density gradient and centrifuged at 25,000 rev/min for 90 min in a Beckman SW27 rotor.

The zone containing virus particles was recovered with an ISCO Model 640

1. Electron micrograph of purified RSV nega- tively stained in 2% uranyl acetate. X100,000.

2. Agar gel diffusion test showing serolo- gical relation between RSV in the Philip pines and Thailand. The center well con- tains purified RSV in the Philippines and the outer wells contain antisera to RSV in the Philippines (P) and Thailand (T), and phosphate buffer.

UA5 scanner and centrifuged at 40,000 rev/min for 60 min. The purified virus fraction had maximum UV adsorption

selected hills from each plot were examined. Scoring followed the Standard evaluation system for rice. Disease intensity was calculated:

% disease intensity = sum of disease score × 100

maximum disease score × no. of leaves examined

Disease intensity increased significantly with increased N but differences in grain yield were not significant (see table).

Timing of planting and variety for rice tungro virus disease (RTV) control

R.C. Cabunagan, Z.M. Flores, H. Hibino, F. Elazegui, and T.W. Mew, Plant Pathology Department, IRRI

We studied time of planting and variety relationship to RTV incidence in first and second crop transplanted rice at Guimba, Nueva Ecija, Philippines. The first crop was established in Jun, Jul, Aug, and Sep and the second crop in Oct, Nov, Dec, and Jan. Twenty-one- day-old seedlings of IR36, IR42, IR50, IR58, IR64, and TN1 (susceptible

at 260 nm, and UV adsorption ratio at 260 nm and 280 (A 260/280 ) was 1.9–2.1. Purified virus particles were about 60 nm in diameter (Fig. 1).

Five 1-ml aliquots of purified virus fractions, of which A 260 nm was adjusted to 1.0, were injected into 2 rabbits at 2- wk intervals. The first four injections were intramuscular, the last injection was intravenous. One week after the last injection, antisera were collected.

The antisera had a titre of 1:1280 in both ring-interface precipitin and double agar gel diffusion tests. In the gel diffusion test, a single band was formed between purified RSV and the antisera, and between RSV and antiserum to RSV from Thailand. The reaction bands fused (Fig. 2), indicating that RSV in the Philippines and in Thailand are serologically indistinguishable.

check) were transplanted in 2- × 2-m plots with 20 × 20 cm between hills and 2–3 seedlings/hill. The plants were subjected to natural RTV infection in the field.

At 30 d after transplanting, vector leafhopper populations were estimated by average leafhopper numbers/ 10 sweeps in the plots; RTV-associated virus incidence was determined serologically.

virescens and N. nigropictus, were present in the area. N. virescens was predominant. Fewer than 1 insect/sweep was obtained in plots planted in Jun. Leafhopper catches continued low for

Two leafhopper species, Nephotettix

IRRN 12:3 (June 1987) 25

Yield

Jul and Aug plantings, but increased for Sep plantings and reached 12 insects/ sweep for Oct plantings. The population declined during the relatively cool months of Dec and Jan (Fig. 1).

Incidence of the bacilliform virus (RTBV) and the spherical virus (RTSV) increased with leafhopper populations. Regardless of month of planting, RTSV incidence was present (Fig. 1b). Infection with RTSV alone did not cause RTV symptoms. Dual infection with RTBV and RTSV was observed in Jun, Sep, and Oct plantings. Regardless Average density of the vector leafhoppers (a) and incidence of RTBV and RTSV (b) at 30 d after of month of planting, TN1 was most transplanting in 6 varieties transplanted monthly from Jun 1985 to Jan 1986; and incidence in infected, followed by IR36 and IR42 each variety regardless of month of transplanting (c).

(Fig. 1c). IR50, IR58, and IR64 were seldom infected.

A scoring system for rice yellow mottle virus disease (RYMV)

V. T. John and G. Thottapilly, International Institute of Tropical Agriculture, Nigeria

RYMV, an African specific disease of lowland rice varieties, has been studied for its etiology and to screen for resistance. But a standard evaluation system for this disease has not been

by enzyme-linked immunosorbent assay (ELISA). Others with little or no symptoms give positive reactions with ELISA.

The scoring system we propose is compatible with the Standard evaluation system for rice. Scores are based on leaf color, mottling, plant height, flowering,

Table 2. Differential varieties for RYMV. reported.

The disease is systemic and variable Score Resistance

grade Varieties

under different growing conditions. Symptoms vary with age of host. 0 HR Oryza glaberrima accessions

Different varieties show different 2 R Moroberekan, LAC23 symptoms. Even after repeated 4 MR OS6, ITA235 inoculations, some immune varieties do 7 S BG90-2, IR5

not show any virus serologically, even 9 HS ITA212

Table 1. Scoring system for RYMV.

such as Tog 5612, Tog 5681

Sero-diagnosis b

ELISA Agar-gel diffusion

Score Resistance a Leaf color Stunting Flowering

0 HR Green Nil 1

Normal R Green Nil Normal + ±

2 R Green Nil Normal ++ + (weak) 3 R Green with sparse dots/streaks Negligible Normal +++ + 4 MR Green with visible mottling Slight Normal +++ ++ 5 MR Light green, mottled 25% Slight delay Highly positive 6 S Pale green 50% Delayed Highly positive 7 S Pale yellow 75% Delayed Highly positive 8 S Yellow >75% No flowering Highly positive 9 HS Yellow, orange >75% Death of plants Highly positive

– –

a HR = highly resistant, R = resistant, MR = moderately resistant, S = susceptible, and HS = highly susceptible. b ± = doubtful, – = negative, + = low virus content, ++ = high virus content, +++ = very high virus content.

and sero-reaction determined by agar- gel diffusion and ELISA techniques. The serological techniques are for restricted use in critical laboratory tests. Most field scores can be based on visual symptoms.

In the score range, 0 represents immunity and 9 extreme susceptibility (death of infected plant) (Table 1).

The actual score range is typified by certain rice varieties which when inoculated display characteristic symptoms (Table 2).

Crown sheath rot incidence in West Bengal

D. K. Nayak and H.S. Chakrabarti, Rice Research Station, Chinsurah, Hooghly, West Bengal, India

Early symptoms of crown sheath rot were reddish brown lesions in patches on the outer leaf sheaths at the crown of the plants. Gradually, the lesions spread throughout the crown sheaths and became dark brown to black. At maturity, clusters of perithecia were produced in the lesions. In severely affected clumps, the culms rotted causing incomplete exsertion and leaf drying (see figure).

Microscopic examination of the rotted crown sheaths showed the

26 IRRN 12:3 (June 1987)

Incidence of crown sheath rot disease in rice in West Bengal.

presence of Gaeumannomyces graminis var. graminis, characterized by hyphae with distinct hyphopodia and beaked perithecia that produced unitunicate asci with eight long, curved ascospores.

Nitrogen level, cultivar, and R. solani isolate effect on sheath blight (ShB) development

A. K.M. Shahjahan, N. Fabellar, and T. W. Mew, Plant Pathology Department, IRRI

Eight rice varieties differing in duration, plant height, and ShB susceptibility were grown in 30-cm-diam pots in the greenhouse with 2 N levels: 1.6 g and 3.2 g/pot. N was applied in 2 equal splits at 21 d after transplanting and at panicle initiation. Staggered planting synchronized booting.

Ten isolates of R. solani differing in growth rate, sclerotia production, and culture type were selected from 98 isolates collected from rice, grass, millet, maize, water hyacinth, and weeds. Plants were inoculated at booting with inocula prepared in a rice hull:rice grain medium. About 100 ml of the inocula was placed between tillers. Inoculated plants were covered with polyethylene sheets at night.

recorded at 5d intervals. The ratios of Lesion height/plant height was

1. Vertical development of ShB in IR58 by different isolates of R. solani at 2 N levels. IRRI, 1987.

leaf to sheath area infection were development. However, there was an compared 28 d after inoculation. isolate × N interaction.

Development of relative lesion height Isolate RS72-1 produced the lowest (RLH) and percent area infected (PAI) RLH as well as PAI in all varieties and by isolates of R. solani differed among was the least virulent isolate tested varieties. The influence of N level was (Fig. 1,2). The other isolates developed apparent only at later stages of lesion higher RLH and PAI in IR58 and

IRRN 12:3 (June 1987) 27

Taichung 176 varieties. Himali and Purple were heavily infected. Infection was uniform and distributed throughout the plots. Aggregate infected area was about 1.5 ha. Although infection was severe and uniform, grain filling was not much affected, maybe because it was a late foliar infection.

The combination of rainy weather, strong winds, and moderate temperatures in Kathmandu favored rapid disease spread. Maximum and minimum temperatures Jun-Oct were 28 °C and 19 °C. Total rainfall was 1,040 mm in 87 d.

regions: Khurkot, Armadi, and Shibalaya Panchayat in Parbat district; Kalika and Mulpani Panchayat, including Baglung Bazar, in Baglung district, and Ratnechour Panchayat in Myagdi district. Local varieties Gudura, Gauriwa, Jarneli, Aanadi, Aagani, and Panhela, and improved varieties Masuli and Khumal 3 were infected. Most of the incidences were in river basin areas (774 m) up to the mid-range of hills (1,084 m). Infection was mostly in shaded areas.

BB also was found in the western hilly

Relationship between growth rate, sclerotia production, and virulence

2. Vertical development of ShB in IR64 by different isolates of R. solani at 2 N of isolates of Rhizoctonia solani levels. IRRI, 1987. Kuhn

IR1317 (short varieties) than in in addition to other factors, ShB Narnpungbyeo, Ta-poo-cho-z, and IR26 development will be influenced by the (tall varieties). The results suggest that, virulence of the pathogen isolate.

Bacterial blight (BB) in hilly regions victim. Later, improved varieties IR5, of Nepal Jaya, Padma, and IR24, and some local

varieties were infected. This disease has H. K. Manandhar, B. J. Thapa, and been confined to hilly regions. P. Amatya, Division of Plant Pathology, In a disease survey in Sep 1986, BB Khumaltar, Lalitpur, Nepal symptoms were observed in the

Sorahkhutte, Nayabazar, and Mhaipi BB caused by Xanthomonas campestris areas (altitude about 1,238 m) of pv. oryzae (Ishiyama, 1922) Dye was Kathmandu valley. Blighted specimens first observed in the terai region with the were tested in the laboratory and BB introduction of high-yielding rice was confirmed. The disease was found varieties. Taichung Native 1 was the first in Himali, Purple, Khumal-3, and

A. K. M. Shahjahan, N. Fabellar, and T. W. Mew, IRRI

Cultures of Rhizoctonia solani causing sheath blight were isolated from diseased specimens of rice, grass, weeds, water hyacinth, maize, and millet from fields on the IRRI farm and in Laguna Province, Philippines. Growth rate (regression coefficient), sclerotia production (no./plate in 10 d), and cultural characteristics of 98 isolates were studied using potato dextrose agar- (PDA) medium enriched with 0.1% urea.

Virulence of 10 isolates representing different culture types, growth rate, and sclerotia production were tested on IR58

28 IRRN 12:3 (June 1987)

Control of rice pests with phosphamidon 85% WP

M. Velusamy and M. Subramanian, Rice Research Station, Tamil Nadu Agricultural University, Ambasamudram, Tamil Nadu, India

Growth rate, sclerotia production, culture type, and virulence of 10 isolates of R. solani a IRRI, 1987.

Isolate Growth Host Culture type b rate c Sclerotia Virulence d

no. (mm/h) (no./plate) (RLH %)

RS9-1 Rice I 2.9 ab 55 bc 68 abc RS16-1 Rice III 2.5 b 55 bc 62 abc RS26-1 Grass IV 2.8 ab 9 d 57 bcd RS27-1 Millet II 3.2 a 25 cd 75 a RS44-8 Rice II 2.8 ab 35 bc 65 abc RS52-2 Rice II 2.7 ab 33 c 52 cd RS64-4 Rice III 2.8 ab 60 bc 57 bcd RS68-4 Rice V 2.9 ab 134 a 74 a RS72-1 Rice VI 1.3 c 22 cd 43 d RSl4-3 Rice IV 2.8 ab 16 cd 72 ab

a Means of 3 replications. In a column, means followed by a common letter are not significantly dif- ferent at the 5% level by DMRT. b All the R. solani isolates were grouped into six culture types based on the colony color, growth characteristics, size and pattern of sclerotia production in PDA + 0.1% Relationship between growth rate of 10 isolates urea medium. c Growth rate was calculated by regression analysis of linear growth over time. d Viru- of R. solani in agar medium and virulence

lence measured as RLH developed in IR58 in 20 d after inoculation. RLH % = plant height × 100 measured as RLH (%) in IR58. IRRI green- house, 1987.

lesion height

grown in pots in the greenhouse with 1.6 g N/30-cm pot. IR58 was inoculated at booting and lesion height and plant height were measured 20 d after inoculation.

The 10 isolates differed in growth rate, sclerotia production, and virulence (see table). Growth rate varied from 1.3 to 3.2 mm/h and sclerotia production from 9 to 134 sclerotia/plate. No

correlation between growth rate and sclerotia production ( r = 0.23 ns) or between sclerotia production and virulence ( r = 0.37 ns) was noted. The correlation was significant ( r = 0.78**) between growth rate and virulence measured as relative lesion height (RLH) in IR58 20 d after inoculation (see figure), but if the extreme values for RS72-1 were excluded, the correlation

coefficient becomes nonsignificant ( r = 0.66ns). The mean growth rates of the 9 other isolates (excluding RS72-1) do not differ much (2.5 to 3.2 mm/h). Virulence varied from 52 to 75%.

The most virulent isolate (RS27-1) with the highest growth rate was isolated from millet grown during the dry season in an upland field following rice.

Two rice varieties were planted for four whorl maggot leaf damage were counted seasons at Ambasamudram in 1984-85 45 d after transplanting (DT) in the first (TKM9 in Jun-Oct and IR20 in Sep- planting and 30 DT in the second

Spraying three times was most effective. With only 1 application,

Feb). Phosphamidon at 210 g ai/ha was planting. sprayed in 4 treatments(see table). Gall midge onion shoots, stem borer deadhearts, green leafhoppers, and 1 spray 20 DT was most effective.

Effect of phosphamidon 85% WP on rice insect pests in wet lowlands. a Tamil Nadu, India, 1984-85.

1984 1985

Application Jun - Oct b Sep - Feb c Jun - Oct d

time (DT) Sep - Feb e

GM Yield GM GLH WM Yield GLH Yield GM (%) (t/ha)

SBDH Yield (%) (no./5 (%) (t/ha) (no./5 (t/ha) (%) (%) (t/ha)

sweeps) sweeps)

20 - 5.9 b 7.0 b 26.3 c 43 b 12.4 ab 2.8 a 10.9 d 5.4 b 23.6 d 21.7 b 4.1 a

1.8 a 6.9 b 15.8 a 21 a 11.2 a 3.2 a 7.2 bc 5.9 b 16.2 c 16.6 a 4.5 a 40 4.6 b 7.0 b 23.7 bc 37 b 14.5 b 4.0 a 7.0 b 5.9 b 12.0 b 60 3.9 a 6.9 b 20.9 b 28 a

14.6 a 4.5 a

20, 40, 60 11.5 a 3.4 a 9.2 cd 5.9 b 10.1 ab

1.7 a 7.5 a 21.2 b 22 a 13.8 b 3.2 a 5.2 a 14.5 a 4.8 a

6.1 a 8.8 a 15.5 a 4.7 a a GM = gall midge, SBDH = stem borer deadhearts, GLH = green leafhopper, WM = whorl maggot. In a column, numbers followed by the same letter are not significantly different at the 0.05% level. b No SBDH and GLH infestations. c No SBDH. d No GM and SBDH. e No GLH and WM.

IRRN 12:3 (June 1987) 29

Effect of low soil phosphorus and pH on bacterial blight (BB)

A. H. Mondal, N. R. Sharma, M. Islam, A. Haque, and S. A. Miah, Bangladesh Rice Research Institute, Joydebpur, Gazipur, Bangladesh

We studied the effect of low available soil P and pH on BB development in IR8 rice. Four soil samples were collected from Bogra, Rangpur, and Gazipur districts of Bangladesh: Magura (11 ppm P and pH 4.4), Madhupur (14 ppm P and pH 5.4), Mawnapathar (15 ppm P and pH 4.3), and Vagnahati (5 ppm P and pH 5.5).

IR8 seedlings were grown in pots on

Effect of low P on BB development. Bangladesh. a

Available P BB SES c

score Soil (ppm) pH lesion b

(%)

Mawnapathar, Gazipur 15 4.3 30.15 b 7 Vagnahati, Gazipur 5 5.5 14.99 a 5 Magura, Bogra 11 4.4 24.46 b

14 5

Madhupur, Rangpur 5.4 21.65 b 5

a Means of 3 replications. b Figures followed by the same letter are not significantly different at P 0.05 level. c Standard evaluation system for rice ratings.

those soils. Plants were fertilized with of Xanthomonas campestris pv. oryzae 100 ppm N from urea and 40 ppm K at maximum tillering. from muriate of potash, but no P was Lesion length was significantly lowest added. They were inoculated by leaf (15%) 21 d after inoculation in clipping with a 72-h-old bacterial culture Vagnahati soil (see table).

Pest Control and Management INSECTS

Elophila sp.? africalis Hampson (Lepidoptera: Pyralidae): A new pest of azolla in Sierra Leone

S. J. Fannah, WARDA, Regional Mangrove Swamp Rice Research Station, Rokupr, Sierra Leone

A research program initiated in 1981 uses azolla as a biofertilizer for rice in associated mangrove and inland valley swamps. Agronomic trials in experiment station and farmers’ fields in Sierra Leone and Guinea involve both local and exotic azolla to identify and select strains with competitive biomass production and adaptability.

An outbreak of leaf-feeding insect larvae on Azolla pinnata var. imbricata strain PI-I37 occurred in late 1985 at Rokupr. Larvae were collected and

Duration of growth stages of Elophila sp.? afri- calis Hampson reared on Azolla pinnata var. imbricata at Rokupr, Sierra Leone, 1985.

Growth Duration (d) Observations stage Range Average (no.)

Egg 4-54.3 25 batches Larva 18-25 23.1 236 Pupa 4-5 4.6 51 Adult 3-4 3.3 75

reared in the laboratory until adults emerged.

The moth was identified as Elophila sp.? africalis Hampson by J. D. Bradley of the Commonwealth Institute of Entomology, British Museum (National History). This species is reported to have been reared only from Pistia.

This is the first time E. africalis has been found on azolla in Sierra Leone. Other species in the genus Elophila have caused considerable damage to azolla at IRRI in the Philippines.

In preliminary studies of the

Leaffolder (LF) population on rice under drought

R. K. Patel, M. P. Janoria, and A. K. Bhowmik, Jawaharlal Nehru Krishi Vishwavidyalaya, Jabalpur, Madhya Prarlesh, India

An insect population buildup is influenced by weather. During the 1986 wet season, a drought prevailed in most of Madhya Pradesh, with 1 wk cloudy weather and no rain 20 Aug-10 Sep around the Jabalpur district. LF Cnaphalocrocis medinalis attacked most

reproductive biology of E. africalis in our laboratory at room temperature and 89-92% relative humidity, moths emerging from larvae collected from infested cultures of A. pinnata var. imbricata were the source of insects. Females deposited eggs, in batches of 16 to 165, on the adaxial side of the floating azolla frond close to the edge. Neonate larvae emerged 4 d later (see table).

wide distribution in Sierra Leone. Field surveys indicated E. africalis has

ricefields. A limited roving survey in Sep noted

incidence on dwarf and tall rice varieties in both rainfed and irrigated fields. Leaf damage was moderate in fertilized fields. At the University Nucleus Seed Production Farm, average intensity was 2.0 damaged leaves/ hill on short- duration Poorva and 5.8 damaged leaves/ hill on medium-duration IR36.

The long dry spell interrupted by cloudy weather may have adversely affected the numbers of natural enemies, promoting LF buildup.

30 IRRN 12:3 (June 1987)

Pest survey in Kalutara district, Sri Lanka

N. D. Delpachitra and D. L. Wickramasinghe, Regional Agricultural Research Centre, Bombuwela, Sri Lanka

We surveyed rice insect pests and natural enemies in farmers’ fields in the 1984 Apr-Aug growing season.

Kalutara district was divided into 3 districts and 2 fields of 0.6 ha or more were selected in each district. Distance between fields was at least 5 km. The rice variety grown in the selected fields was the most common variety.

from seedling to ripening. Fifteen sweeps/field were taken for insect counts and five 1-m 2 samples were observed for damage.

The harmful insects present in considerable amounts were whitebacked planthopper (WBPH) Sogatella furcifera (Horvath) at the vegetative phase and paddy bug Leptocorisa oratorius at the reproductive phase.

Natural enemies found included spiders, dragonflies, mirid bugs, and hymenopteran parasites (see table).

The WBPH at the vegetative phase dropped in number with crop age. This decrease may be due to the presence of natural enemies.

previous seasons.

Assessments were made once a month

Farmers had used chemical control in

Number of insects/15 sweeps in farmers’ fields. Sri Lanka, 1984.

Insect pests (no.) Natural enemies (no.)

WBPH Paddy bug Spiders Dragonflies Mirid bugs Hymenopterans District Area

Seedling stage Kalutara Nagoda 0 0 0 3 16 0

Uggalboda 51 0 0 3 1 0

Horana Kananwila 23 0 0 0 5 18 Kulupana 9 0 0 1 5 86

Matugama Matugama 16 0 1 7 5 5 Bellana 56 0 0 0 2 13

Tillering Kalutara Nagoda 18 8 1 2 3 0

Uggalboda 133 9 6 14 9 0

Horana Kananwila 17 2 10 1 0 13 Kulupana 29 136 0 1 0 –

Matugama Matugama Bellana

Kalutara Nagoda Uggalboda

Horana Kananwila Kalupana

Bellana Matugama Matugama

Kalutara Nagoda Uggalboda

Horana Kananwila Kulupana

Matugama Matugama Bellana

Kalutara Nagoda Uggalboda

Horana Kananwila Kalupana

Matugama Matugama Bellana

35 0 0 0

0 18 0 36

19 8 2 16

30 12 2 0

0 52 0 12 0 19 0 48 0 67 0 35

0 25 0 144 0 87 0 170 0 11 – –

2 1

Booting 22

4 3 2 2 1

Flowering 12

1

9 2

0 0

Ripening 0 0 0 0 1 –

4 3

2 1 0 1 1 6

4 0 0 0

0 1

5 0 0 0 – –

0 40

1 14

1 2 0 0

0 0 0 0 2 0

0 0 0 0 – –

12 40

13 22 24 13 0 0

5 0 0 0

10 0

0 0 0 0 – –

Trap crop for green leafhopper (GLH) and tungro (RTV) management

R. C. Saxena. International Centre of Insect Physiology and Ecology and IRRI, and H.D. Justo, Jr., IRRI

A trap crop is a small, early planting of a crop that is more attractive to insect pests than the crop to be protected and effective enough to justify using it instead of other control measures.

intensive chemical control of Nephotettix virescens in May-Sep 1986. RTV-susceptible IR42 was used as both trap crop and main crop.

We tested using a trap crop instead of

Table 1. RTV incidence in ricefields with and without a trap crop. a IRRI, May-Sep 1986.

Treatment b Proportionate area/ha

RTV Combined incidence c RTV incidence Date planted

(%) (%)

2-row trap crop 9 May 0.074 0.3 Main crop 23 May 0.926 8.2 a 3-row trap crop 9 May 0.109 0.5 Main crop 23 May 0.891 7.0 a 4-row trap crop 9 May 0.144 0.5 Main crop 23 May 0.856 4.7 a Treated control d 9 May 1.000 6.4 a Untreated control e 23 May 1.000 36.8 b 36.8 b

level by DMRT. b Trap crops were sprayed. c Proportionate RTV incidence (%) in trap crop was not

a Av of 4 replications. Means followed by a common letter are not significantly different at the 5%

analyzed. d Main crop fields sprayed with cypermethrin @ 0.05 kg ai/ha. e Unsprayed fields.

In trap-crop fields, 2, 3, or 4 border after transplanting (DT) with

8.5 a

7.5 a

5.2 a

6.4 a

rows were planted 15 d before the main cypermethrin at 0.05 kg ai/ha. The main crop and sprayed each week up to 60 d crop was not sprayed.

IRRN 12:3 (June 1987) 31

Rice GM Orseolia oryzivora is a serious

pest of wet season (WS) rice at Edozhigi, an irrigated area in Nigeria. The rainy season in this area is Jun-Oct and farmers transplant in Sep.

We measured GM incidence on FARO 27 and FARO 29 in the 1985 WS on samples of 50 hills/variety, replicated 3 times. Percentage of silvershoots was calculated as the ratio

M.N. Ukwungwu, Rice Research Programme, National Cereals Research Institute, Badeggi, P.M.B. 8, Bida, Nigeria

Influence of age of crop and time of planting on gall midge (GM) incidence

Fields without a trap crop, but sprayed with cypermethrin, were the treated control. Unsprayed fields without a trap crop were the untreated control.

Plot size was 11 × 17 m. Each treatment was replicated four times.

At 65 DT, RTV incidence was significantly higher in the untreated control than in trap or insecticide- treated fields (Table 1). Relatively higher nymphal and adult GLH populations were recorded.

and insecticide-treated fields than in the untreated control (Table 2). Although yield was highest in insecticide-treated fields, the cost of cypermethrin lowered net gain. Limited insecticide use also conserves natural enemies of rice pests.

Yields were significantly higher in trap

Rice thrips Stenchaetothrips biformis (Bagnall) effect on yield

N. D. Delpachitra and D.L. Wickramasinghe, Regional Agricultural Research Centre, Bombuwela, Sri Lanka

We evaluated thrips damage and subsequent yield in highly susceptible variety Bg 94-1. We assumed that natural thrips infestation would be uniform over all plots, if not controlled. Carbofuran at 1 kg ai/ha was used in an

Thrips damage and rice yield under chemical control, Sri Lanka, 1983.

32 IRRN 12:3 (June 1987)

Table 2. Value of yields with and without trap crop after deducting cost of cypermethrin a . IRRI, May–Sep 1986.

Area (ha) Combined Value of Cypermethrin Cost d Net value Treatment yield yield b applied c ($/ha) ($/ha)

Trap crop Main crop (t/ha) ($/ha) (liters/ha)

2-row trap crop and 0.074 0.926 4.5 a 787.50 0.592 14.21 713.29 a

3-row trap crop and 0.109 0.891 4.2 a 735.00 0.872 20.93 714.07 a

4-row trap crop and 0.144 0.856 4.4 a 770.00 1.152 27.65 742.35 a

Treated control 0 1.000 4.9 a 857.50 8.000 192.00 665.50 ab Untreated control 0 1.000 3.3 b 577.50 0 0 577.50 b

main crop

main crop

main crop

ent at the 5% level by DMRT. b US$ = P20; value of rice (NFA price) = $0.175 kg. c Eight applica- a Av of 4 replications. In a column, means followed by a common letter are not significantly differ-

tions to trap crop rows and treated control plots @ 0.05 kg ai/ha per treatment. d Cost of cypermeth- rin Jul 1986 = $24/liter.

The International Rice Research Newsletter and the IRRI Reporter are mailed free to qualified individuals and institutions engaged in rice production and training. For further information write: IRRI, Communication and Publications Dept., Division R, P. O. Box 933, Manila, Philippines.

experiment in late Nov 1983. A second experiment used different insecticides. Damage was rated according to the Standard evaluation system for rice 3- 4 wk after sowing. After assessment, the plants were fully protected from other pest attacks.

In carbofuran-treated plots, thrips damage was rated as 1; in untreated

control plots, 7-9. Average grain yield in treated plots (3.34 t/ ha) was significantly different from that in the untreated plots (2.34 t/ ha) at 5% level of probability. Plots treated with different chemicals had a control rating of 1 for all but triazophos, which rated 5; untreated plots rated 7 (see figure). Yields varied.

GM incidence by age of rice crop. Edozhigi, Nigeria, 1985 wet season.

Days after transplanting

30 40 50 60 70

LSD (0.05)

Silvershoots a (%)

FARO 27 FARO 29 Mean

13.8 (21.6) 11.8 (17.4) 12.8 15.4 (22.6) 18.0 (25.1) 16.7 14.5 (21.7) 18.2 (25.2) 16.4

7.9 (16.1) 15.3 (22.9) 11.6 7.7 (16.0) 10.4 (18.6) 9.1

10.2 6.7 a Figures in parentheses are transformed angular values, LSDs refer to them.

of number of silvershoots to tillers/50 prone to GM infestation at 30-50 DT hills at 30, 40, 50, 60, and 70 d after and medium-maturing FARO 29 at 40- transplanting (DT). GM incidence also 60 DT (see table). The later the was measured at 50 DT on FARO 27, transplanting date, the higher the GM FARO 29, and ITA212 transplanted incidence (see figure). But many local 20 Aug, 25 Sep, and 25 Oct. farmers avoid early planting because

Early-maturing FARO 27 was more they grow upland crops before rice.

Effect of planting time on GM incidence. Edozhigi, Nigeria, 1985 wet season.

Host plants for yellow rice borer (YSB) Scirpophaga incertulas and white stem borer (WSB) S. innotata

A. Arvind, Faculty of Agriculture, Annamalai University, Tamil Nadu, India

We measured YSB and WSB survival on two weed species common in ricefields. Individually caged plants of Cyperus rotundus and Cynodon dactylon were infested separately with newly emerged first-instar YSB and

WSB larvae.

larvae bored into the stem, fed on the inner contents, and pupated below the soil surface. Survival on C. rotundus was 78% for YSB and 53% for WSB.

On C. dactylon, the larvae scraped the inflorescence peduncle, fed a little on the inner stem contents, but failed to pupate. It could be that stem borer larvae initially feed on C. dactylon, then migrate to a newly transplanted rice crop.

On C. rotundus, both YSB and WSB

Walking the rice paddy for pest the effect on yield of walking in the sampling does not affect yield paddy.

Variety IR64 was transplanted 20 d G.S. Arida and B.M. Shepard, IRRI after seeding at 25 × 25 cm. The field

was divided into 24 plots measuring 2 × It is necessary to walk the rice paddy to 5 m each. Four treatments (see table) sample insect populations. We measured were replicated six times in a

randomized complete block design.

yield. There was no significant difference in

Effect on yield of walking through rice paddy. IRRI. 1986.

Walking (no./wk)

Yield (t/ha)

0 a 2.5 1 2.5 3 6

2.5 2.4

a Plots not walked on 14-77 d after transplanting.

Occurrence of a virulent rice gall midge (GM) Orseolia oryzae Wood- Mason biotype(?) in Andhra Pradesh, India

J.S. Bentur, T.E. Srinivasan, and M.B. Kalode, Directorate of Rice Research, Rajendranagar, Hyderabad 500030, India

During the 1986 wet season, GM severely damaged rice crops in northeastern Andhra Pradesh, where large tracts were planted to GM- resistant varieties Phalguna (RPW 6-17) and Surekha (developed from IR8/ Siam 29). These varieties were released in 1977 and 1976.

We assessed damage in cooperation with the extension staff of the Department of Agriculture, Andhra Pradesh.

Damage in Phalguna and Surekha averaged more than 50% silvershoots. Maximum damage approached 96%.

Susceptible varieties were severely damaged — CR1014, 33%; Mahsuri, 57%; RNR17, 78%; Sona, 84%; and Swarna, 88%.

high rainfall (410 mm) late Jun to mid- Aug, and frequent cyclonic storms in Sep and Oct, resulting in cloudy and humid periods. Farmers also were not familiar with control measures because GM had not occurred severely for more than 10 yr. Studies over 10 yr under the AICRIP coordinated entomology program have established 3 distinct biotypes, based on reactions to differential donors Eswarakora and

Pest buildup was probably favored by

IRRN 12:3 (June 1987) 33

Seasonal changes in the stem borer (SB) Maliarpha separatella populations

M.N. Ukwungwu, Rice Research Programme, National Cereals Research Institute (NCRI), Badeggi, P.M.B. 8, Bida, Nigeria

We studied seasonal population

Siam 29/Leaung 152 and their derivatives. The Andhra Pradesh population represented biotype 1.

Apparently, the resistance in Phalguna and Surekha has broken down in response to a new, more virulent biotype.

donors other than Siam 29 also were affected by the new population. In small minikit plots, Pothana (an Eswarakora derivative) and IR36 (a Ptb derivative) exhibited 40.6% and 22.2% silvershoots. These preliminary studies point toward a possible “new” biotype of GM.

Other resistant varieties involving

Some common predators of rice insect pests

N. Q. Kamal, A.N.M.R. Karim, and S. Alam, Bangladesh Rice Research Institute (BRRI), Joydebpur, Gazipur, Bangladesh

We collected predators from ricefields using sweep nets and took visual counts

of insect predators of rice insect pests Rice Research Institute, R. Madge, CIE, 1981-84 (see table). A. T. Barrion of the London, and M. S. K. Ghauri, CIE, Entomology Department, International London, identified the specimens.

A new brown planthopper (BPH) biotype in Parwanipur, Nepal resistance gene (resistant [R] to biotypes

1 and 3) were susceptible to the G.L. Shrestha, National Rice Improvement Program (NRIP), Parwanipur, Birganj, Nepal; and R.R. Adhikary, Parwanipur Agriculture Station, Parwanipur, Birganj, Nepal

We multiplied the local BPH population on susceptible TN1 during the 1984-85 winter season. The biotype was identified by screening on differential rice varieties in the greenhouse. We repeated the screening twice, with three replications each. Damage was scored on individual seedlings using the Standard evaluation system for rice.

Mudgo and IR26 with Bph 1

Parwanipur biotype (see table). ASD7, CR94-13, and IR36 with bph 2 gene for resistance (R to biotypes 1 and 2 but susceptible to biotype 3) were susceptible. The Parwanipur BPH population is not biotype 1, biotype 2, or biotype 3. Rathu Heenathi ( Bph 3 gene) and Babawee ( bph 4 gene) were resistant to the Parwanipur BPH biotype, as were Ptb 33 and Hondarawala with two genes ( bph 2 + Bph 3 ) for resistance.

The Parwanipur BPH population appears to be a new biotype. The gene complex of IR56 and IR58 is not fully understood.

Comparison of differential varietal reactions to BPH biotypes 1, 2, and 3, and the Parwanipur BPH biotype. Birganj, Nepal, 1984-85 winter.

Gene for resistance Reaction to local biotypes of BPH Some insect predators of rice insect pests and differential recorded at BRRI farm, Joydebpur, Gazipur, Bangladesh, 1981-84.

variety Biotype 1 Biotype 2 Biotype 3 biotype

Predator Intensity Mudgo R S R S

Reaction to Parwanipur

Bph 1

COLEOPTERA Anthicidae Formicomus sp. Carabidae

IR26 bph 2

ASD7

Ophionea ishii ishii Habu High Ophionea indica Thunberg Bph 3

CR94-13

Staphylinidae Rathu Heenathi

R

R R

R

S

R R

R

R

S S

R

S

S S

R Paederus fuscipes Curtis High

Cicindela venosa Kollar Moderate C. grammophora Moderate

Cicindellidae

HEMIPTERA Miridae

Cyrtorhinus sp. Moderate Tythus sp. Moderate

Stenonabis nr. tagalida Stal Low

Limnogonus sp. Moderate

Mesovelia vittigera (Horvath) Moderate

Microvelia douglasi atrolineata High

Nabidae

Gerridae

Mesoveliidae

Veliidae

Bergroth Pentatomidae

Anthocoridae

DIPTERA Chloropidae

Zincroma coerulin Linnaeus Moderate

Orius tantillus (De Motschulsky) Moderate

Anatrichus pygmaeus Lamb Moderate

bph 4

bph 2 + Bph 3 Babawee R R R R

Ptb 33 R R R R Hondarawala R R R R

TN1 S S S S No resistance gene

fluctuations of M. separatella, a major pest of rice in Nigeria, Jan-Dec 1982 at Badeggi research farm. Ten hills of susceptible variety FARO 11 were dissected at 10-d intervals from transplanting to harvest to count borers.

Insect population was about four times higher in crops transplanted in the dry season (Nov-May) than in the wet

34 IRRN 12:3 (June 1987)

farmers’ fields. However, in Feb-Apr, no farmers’ rice crops were in the field and the research farm crops attracted borers.

Influence of cultivation on survival of the Malayan black bug in ricefields

B. M. Shepard and V. A. Perez, Entomology Department, IRRI

Black bugs Scotinophara coarctata remain in rice stubble after harvest. If fields are not plowed, the crop ratoons and the bugs continue to feed and reproduce. It is not unusual to find over 100 insects/ hill.

We plowed an approximately 1/8-ha portion of a ricefield after harvest using a carabao with moldboard plow, and immediately placed 14 1-m 2 cages at random in the plowed section and 14 cages in an unplowed section of the same field. Live adults and nymphs of the Malayan black bug in the cages were recorded at 4, 10, 17, 24, and 31 d after plowing.

Significantly fewer black bug adults and nymphs were found inside cages in the plowed field (see figure). Many black bugs were killed outright by the plowing, others died because host plants were destroyed.

2. M. separatella larvae by crop growth stage, Badeggi, Nigeria, 1982.

season (Jun-Oct) (Fig. 1). Regardless of (Fig. 2). Incidence was low Aug-Jan, time of planting, rice was prone to infestation at later growth stages the research farm and in adjoining local Philippines, 1986.

Populations of black bug nymphs and adults in probably because of even distribution on plowed and unplowed ricefields. Palawan,

IRRN 12:3 (June 1987) 35

Bioassay of Beauveria bassiana and Nomuraea rileyi (Deuteromycotina; Hyphomycetes) against the rice leaffolder (LF)

R.M. Aguda, Entomology Department, IRRI, and M.C. Rombach, Boyce Thompson Institute for Plant Research, Ithaca, New York, USA

Rice LF Cnaphalocrocis medinalis and Marasmia spp. are infected with various entomogenous fungi, including Beauveria bassiana, Nomuraea rileyi, Paecilomyces farinosus, and an unidentified entomophthoralean species. These fungi are obligate insect pathogens that might be useful in biological control of LF.

(white muscardine fungus) and Nomuraea rileyi (cosmopolitan pathogen of lepidoptera) on LF C. medinalis. The B. bassiana isolate originated from the brown planthopper from China, the N. rileyi isolate originated from hairy caterpillar Rivula atimeta in the Philippines.

Suspensions of 0, 10 4 , 10 5 , 10 6 , 10 7 , and 10 8 conidia/ml were prepared for both fungi. Thirty 3d-instar LF larvae were dipped in each suspension and left for several minutes on filter paper. Treated larvae were incubated in petri

We tested the virulence of B. bassiana

Effect of buprofezin in controlling green leafhopper (GLH) and tungro (RTV) incidence

S. Mas’ud, and Moeh, Sudjak S., Maros Research Institute for Food Crops, P.O. Box 173, Ujung Pandang, Indonesia

We evaluated an insect growth regulator, buprofezin, in the field against Nephotettix virescens GLH population and RTV infection.

powder (WP) and emulsifiable concentrate (EC), each at 250, 500, and 1,000 g (ml)/ ha. The trial was conducted at Maros in the dry season and at Lanrang in the 1986 wet season in a randomized complete block design with four replications. Plot size was 5 ×

Two formulations were used: wettable

36 IRRN 12:3 (June 1987)

Mortality of LF larvae treated with different entomogenous fungi. IRRI, 1987.

dishes containing rice leaves; the leaves in ED 50% of 7.4 × 10 3 conidia/ml for were renewed daily. Mortality was B. bassiana and ED 50% of 3.5 × 10 5

determined after 1 wk incubation. conidia/ml for N. rileyi.

using Abbott’s formula. Differences figure). The B. bassiana isolate was between fungi species were tested by more infectious to this host. probit analysis. Probit analysis resulted

Mortality percentage was adjusted, Virulence of these fungi differed (see

Table 1. GLH population and RTV incidence at Maros, Indonesia, 1986.

Buprofezin concentration

g (ml)/ha Formulation

GLH a (no./40 hills) Tungro incidence (%)

28 DT 49 DT 56 DT 63 DT

250 10 WP 12.7 a 7.0 a 51 83 500 10 WP 13.2 a 12.7 ab 60 78

1000 10 WP 11.5 a 5.7 a 54 81 250 400 EC 14.0 ab 11.0 ab 49 79 5 00 400 EC 21.7 b 14.5 ab 53 83

1000 400 EC 14.2 ab 8.0 a 45 68 0 (control) – 36.7 c 20.0 b 66 87

a In a column, values followed by the same letter are not significantly different at P 0.05.

10 m. Variety Cisadane was planted at application to 49 DT in Maros and 25-× 25-cm spacing. Urea and TSP 53 DT in Lanrang. RTV incidence was were applied at 40 kg N and 18 kg P / ha monitored weekly until symptoms were 25 and 50 d after transplanting (DT). found. The insecticide was applied first when At Maros, GLH was found 21 DT al GLH was found on trial plots. Counts 8-17 insects/40 hills. At 28 DT, all were made from 1 d after insecticide insecticide rates significantly controlled

GLH (Table 1). By 35 DT, the rates did not significantly differ from each other.

RTV was 45-65% at 56 DT and increased to 68-88% by 63 DT. All insecticide rates tested kept GLH below the economic injury level of 25 insects/hill, but did not prevent RTV.

At Lanrang, GLH was found 48-56 insects/40 hills at 18 DT (Table 2). All insecticide rates tested were ineffective at 25 and 32 DT, but were effective at 39 DT, By 53 DT, treatments were not significantly different from each other. Severe RTV infection was found at 60 DT. All treatments were ineffective in

Knockdown of green leafhopper (GLH) by six insecticides

R.F. Macatula and O. Mochida. IRRI

Some insecticides that control GLH effectively do not always prevent tungro (RTV) infection. This is probably due to slow knockdown, as GLH can transmit RTV before it dies. Using foliar spray and contact toxicity tests, we evaluated four pyrethroids, one carbamate, and one organophosphate in the laboratory for quick knockdown.

In the foliar spray test, 30-d-old potted seedlings of highly susceptible TNl were cleaned, placed on an electrically rotating table, and uniformly sprayed with insecticide, using an Arthur Thomas sprayer. Spray rates were 0.005, 0.15, and 0.01% ai. Control plants were sprayed with distilled water.

Ten minutes after treatment (MAT), the mylar film-caged plants were infested with 20 GLH adults. Knockdown mortalities were recorded up to 24 h after insect release.

In the contact toxicity test, 20 GLH adults were collected from rearing cages, anaesthetized with CO 2 gas for 10 s, and transferred onto petri dishes lined with filter paper. The dishes were placed at the bottom of a Potter’s spray tower and sprayed with insecticide solution.

Treated adults were transferred to 15- d-old untreated TN1 seedlings. Mortality was recorded to 60 MAT.

With foliar spraying, adult mortalities

Table 2. GLH population and RTV incidence at Lanrang, Indonesia, 1986.

Buprofezin GLH a (no./40 hills) Tungro concentration Formulation incidence (%)

(g (ml)/ha 25 DT 46 DT 60 DT

250 10 WP 44.7 ab 19.7 ab 99 500 10 WP 30.2 ab 15.5 a 96

1000 10 WP 39.5 ab 17.5 a 98 250 400 EC 40.7 ab 17.5 a 98 500 400 EC 51.2 b 20.7 ab 97

1000 400 EC 28.0 a 17.7 a 95 0 (control) – 74.5 c 26.7 b 99

a In a column, values followed by the same letter are not significantly different at P 0.05.

suppressing RTV. Buprofezin is slow to only during molting. The delay allows control GLH populations because it acts RTV to be transmitted.

Table 1. Effect of foliar spraying of 6 insecticides on N. virescens adults. IRRI insectary, 1986.

Adult female mortality (%) at indicated time after release b

1 h 3 h 24 h Insecticide a Rate

(% ai)

Alphamethrin 0.01 77 c 79 b 90 b Cypermethrin 0.01 100 a 100 a 100 a Ethoproxyfen 0.01 100 a 100 a 100 a MIPC 0.15 98 b 100 a 100 a Monocrotophos 0.15 79 c 100 a 100 a Deltamethrin 0.005 100 a 100 a 100 a Control – 0 d 0 c 0 c

a Spray volume based on 500 liters water/ha. b Av of 4 replications. In a column, means followed by a common letter are not significantly different at 5% level by DMRT.

Table 2. Effect of contact spray of 6 insecticides on N. virescens adults. IRRI insectary, 1986.

Adult female mortality (%) at indicated time after treatment b

5 min 10 min 20 min 60 min Insecticide a Rate

(% ai)

Alphamethrin 0.01 2 cd 4 c 15 c 16 c Cypermethrin 0.01 70 a 92 a 100 a Ethoproxyfen 0.01 15 b 21 b 36 b 49 b MIPC 0.15 2 cd 4 c 0 d 19 c Monocrotophos 0.15 5 cd 4 c 2 d Deltamethrin

2 de 0.005 79 a 95 a 100 a

Control – 0 d 0 c 0 0 e

means followed by a common letter are not significantly different at the 5% level by DMRT. a S pray volume based on 500 liters water/ha. b Av of 4 replications, 20 GLH/replication. In a column,

100 a

100 a

were significantly high with all 6 pyrethroids deltamethrin and insecticides 1 h after release (Table 1). cypermethrin showed significantly With direct spraying, the synthetic higher knockdown 5 MAT (Table 2).

Effect of synthetic pyrethroid We evaluated 4 synthetic pyrethroids — insecticides on green leafhopper ethoproxyfen (0.1 kg ai/ ha), cyper- (GLH) and tungro (RTV) methrin (0.05 kg ai/ ha), alphamethrin,

and deltamethrin (0.0125 kg ai/ ha) — S.L. Valencia and O. Mochida, IRRI for Nephotettix virescens GLH and

IRRN 12:3 (June 1987) 37

RTV control in the field in 1984 dry season (DS). Wet seedbeds of highly susceptible TN1 and susceptible IR22 were covered with nylon mesh immediately after sowing to protect seedlings from GLH. Starting 1 d after transplanting (DT), 8 insecticide applications were made at weekly intervals. Disease incidence was recorded at 60 DT.

The same materials and methods were used in a 1985 wet season (WS) trial, but insecticide applications were reduced to five.

plots treated with any of the pyrethroids was significantly lower than in the untreated control. Cypermethrin gave the lowest RTV incidence (see table).

In the 1984 DS, RTV infection in

RTV control by 4 synthetic pyrethroids on 2 susceptible rices at IRRI, 1984-85.

RTV b (% infected hills) at 60 DT

Insecticide a Formulation 1984 DS 1985 WS

IR22 TN1 IR22 TN1

Cypermethrin Ethoproxyfen Alphamethrin Deltamethrin Control

5 EC 20 EC 10 EC 2.5 EC

7.8 a 7.8 a

11.5 ab 14.4 ab 30.3 c

9.6 a 21.7 abc 21.3 abc 29.7 bc 81.9 d

2.5 a 2.6 a 3.9 ab 3.3 ab 5.3 b

29.6 ab 22.9 a 39.4 ab 24.1 a 43.4 b

a Insecticide was applied at 1, 8, 15, 22, 29, 36, 43, and 50 DT in the 1984 DS and at 1, 20, 34, 49, and 63 DT in the 1985 WS. b In a column, means followed by a common letter are not significantly different at 5% level by DMRT.

In the 1985 WS, RTV infection was significantly lower on IR22 treated with ethoproxyfen and cypermethrin and on TN1 treated with ethoproxyfen and deltamethrin.

The degree of control with the synthetic pyrethroids improved with more frequent applications early in crop growth. On susceptible varieties, control of RTV by insecticides was low.

Chemical control of rice gall midge (GM) Orseolia oryzivora

D. Dakouo and S. Nacro. INERA - Station de Faroka-Ba, B. P. 910 Boho-Dioulasso, Burkina Faso

A 2-yr study (1982-83) investigated chemical control of GM on irrigated rice in southwestern Burkina Faso, where the pest is prevalent.

Carbofuran at 1.2 kg ai/ ha and deltamethrin at 2.5 g ai/ha in a randomized block design with 5 treatments and 5 replications were evaluated. Plot size was 32 rows of 20 hills. Silvershoots at 45, 60, and 75 d after transplanting were counted on 4 rows/plot. Yield was estimated from 20 rows/plot.

Chemical control of rice GM a . Burkina Faso, 1982-83.

Chemical applied at indicated time Damage Yield

75 DT (t/ha)

0 DT 15 DT 30 DT 45 DT 60 DT (% silvershoots)

Carbofuran Carbofuran

Carbofuran

–

–

– Carbofuran Carbofuran

– –

– –

Deltamethrin –

–

– – –

Deltamethrin Deltamethrin

– – – –

Carbofuran

– – –

Deltamethrin Deltamethrin

1982

Deltamethrin Deltamethrin Deltamethrin

–

–

1983 –

Deltamethrin Carbofuran Carbofuran Deltamethrin

–

Deltamethrin Deltamethrin Carbofuran

–

Deltamethrin –

– –

Deltamethrin

26 b 23 ab 18 ab 20 ab 16 a

21 bc 16 ab 11 a 11 a 11 a

5.39 b 6.31 a 7.31 a 6.40 a 6.68 a

4.91 b 6.46 a 6.91 a 6.12 a 5.91 a

a DT = days after transplanting. In a column and in a year, means followed by the same letter are not significantly different at the 5% level.

Treatments that included at least one application of carbofuran were effective

(see table). Yields were 1-2 t/ha higher than without treatment.

Pest Control and Management WEEDS

Herbicides to control weeds in transplanted rice S. S. Tomar, Sukhadia University, Agricultural Research Station (ARS), Borkhera Kota, Rajasthan, India

In southeastern Rajasthan, labor for

38 IRRN 12:3 (June 1987)

manual weeding is scarce and expensive. I evaluated herbicides in kharif seasons 1984-85.

Seven herbicides at 2 rates of application were compared with hand weeding 20 and 40 d after transplanting (DT) and an unweeded check. The

experiment was laid out in a randomized block design with four replications.

Weed seed ( Echinochloa crus-galli ) was broadcast at 5 kg/ ha immediately after transplanting. Herbicides were applied 6 DT.

Effect of herbicides on weed control in transplanted rice, Kota, India. Pendimethalin at 1.0 and 1.5 kg

Grain yield Weed dry wt Rate (t/ha) Panicles/m 2 Panicle wt (g) (g/m 2 ) at Cost-

Treatment a harvest to-benefit (kg ai/ha) 1984 1985 1984 1985 1984 1985 ratio b

1984 1985

2,4-D EE (G) 0.8 6.7 5.2 312 281 2.8 2.9 170 74 13.2 2,4D EE (G) 1.0 6.9 5.6 321 283 2.7 2.9 167 71 12.5 Oxyfluorfen (G) 0.1 6.1 5.8 311 290 3.2 2.8 190 85 Oxyfluorfen (G) 0.15 6.3 5.8 324 295 3.4 2.9 149 82 Thiobencarb (G) 1.0 6.7 5.8 320 297 2.9 3.0 188 78 14.5 Thiobencarb (G) 1.5 6.7 5.9 295 284 3.0 2.8 185 70

6.5 4.8 298 295 2.9 2.7 209 95 9.9

Anilofos (EC) 0.3 Anilofos (EC) 0.4 6.2 5.3 310 271 2.9 2.8 189 89 – Butachlor (G) 1.0 6.6 5.4 290 242 3.0 3.0 192 95 12.4 Butachlor (G) 1.5 6.8 5.7 315 253 2.9 2.9 190 96

7.1 6.1 332 267 3.5 3.3 130 69 18.4 9.5

Pendimethalin (G) 1.0 Pendimethalin (G) 1.5 6.9 5.7 310 267 2.8 3.0 163 75 10.7 Butachlor (EN) 1.0 5.7 5.6 299 261 2.5 2.8 210 100 10.8 Butachlor (EN) 1.5 6.1 5.7 300 252 3.3 2.8 180 104 8.5 Hand weeding 20 – 7.0 6.0 323 262 3.5 3.5 134 15 7 .0

Unweeded check – 4.6 4.0 264 236 2.4 2.3 232 166 –

CD (0.05) 0.2 0.2 3 4 0.1 0.3 2 2 –

$1/kg; thiobencarb 10 G, $2.15/kg; butachlor 5G, $l.l/kg; pendimethalin S G, $1/kg;butachlor 50 a EE = ethyl ester, G = granules, EC = emulsifiable concentrate, EN = emulsion. Cost of 2,4-D 4G,

EN, $10/liter; oxyfluorfen and anilofos, not available. b Grain, $160/t; C:B averaged over 2 yr.

– –

–

and 40 DT

Pest Control and Management OTHER PESTS

ai/ ha, thiobencarb at 1.0 and 1.5 kg ai/ha, and 2,4-D at 1.0 kg ai/ha were effective in controlling weeds (see table). These treatments had significantly higher grain yield, more effective tillers, and higher panicle weight than the unweeded check. The highest benefit-to- cost ratio was with pendimethalin at 1 kg ai/ha.

The International Rice Research News- letter and the IRRI Reporter are mailed free to qualified individuals and institu- tions engaged in rice production and training. For further information write: IRRI, Communication and Publications Dept., Division R, P. O. Box 933, Manila, Philippines.

Yield loss to rice root nematode Effect of rice root nematode H. oryzae on height and yield of rice. a Tamil Nadu, India, 1984-85. Hirschmanniella oryzae

Treatment Plant ht (cm) Grain Straw

E. I. Jonathan and B. Vela-putham, Nematology Laboratory, Tamil Nadu (g/4 hills) (%) (g/4 hills) (%)

(nematodes/g soil) 30 DT 60 DT At harvest Yield Reduction Yield Reduction

Agricultural University, Trichy 5, India

We conducted two experiments with potted plants to determine yield loss to H. oryzae.

IR20 seedlings raised in sterile soil were transplanted 21 d after sowing at 4 seedlings/ pot. Treatments were rice root nematodes inoculated at 1 and at l0/g soil and an untreated check, in 8

0 38 a 62 a 79 a 44.1 a – 34.1 a – 1 34 b 58 b 70 b 32.2 b 26.9 26.0 b 22.9

10 30 c 54 c 68 c 26.6 c 39.7 19.7 c 42.2 CD (0.05) 1 5.2 – 3.5 –

a Mean for 2 pot experiments, with 8 replications each. DT = days after transplanting. In a column, means followed by the same letter are not significantly different at the 5% level by DMRT.

replications. nematodes/g soil (see table). Straw

nematode/g soil and 40% with 10 and 42% less with 10 nematodes. Yield losses were 27% with 1 yields were 23% less with 1 nematode

Control of rice root nematode with carbofuran

B.N. Routaray, H. Sahoo, and S. N. Das, Nematology Department, Orissa University of Agriculture and Technology, Bhubaneswar 751003, Orissa, India

The effect of carbofuran on populations of rice root nematode Hirschmanniella

mucronata and on growth characteristics of rice were measured in microplot field experiments in 1983 and 1984 rainy seasons. The experiment was laid out in a randomized complete block design with 4 treatments and 5 replications in 16-m 2 subplots. Treatments were seedlings from an untreated nursery (TI), seedlings from a

carbofuran-treated nursery (T2), seedlings from the untreated nursery with carbofuran applied 50 d after transplanting (DT) (T3), and seedlings from the carbofuran-treated nursery with carbofuran at 50 DT (T4). All applications were at 1 kg ai/ha.

Experimental field soil was loamy clay with pH 6.4. Recommended NPK

IRRN 12:3 (June 1987) 39

fertilizer was applied. Healthy 30-d-old Jaya seedlings were transplanted at 20-× 15-cm spacing. Other cultural practices were as needed.

Preplanting nematode populations per 200 cc soil did not differ significantly by year but varied within years: 122.4- 134.6 in 1983 and 109.6-126.0 in 1984.

At harvest, H. mucronata numbers were very low in soil samples of treated nursery and treated plot (see table). Nematode populations per gram root also were low. The number of flowering tillers was higher and fresh root weight was greater. Yields increased with increasing carbofuran application.

Irrigation regime and rice yield

V. N. Khade, B. P. Patil, S. T. Thorat, and S.A. Khanvilkar, Konkan Agricultural University, Dapoli 415712 Maharashtra, India

We assessed the effect of irrigation level on rice yield (Ratna variety) during three dry seasons 1983-86. Soil was medium black, with pH 6.4, 0.87% organic C, and an infiltration rate of 1.0-1.4 cm/ h. Seven treatments were replicated three times in a randomized block design.

One-month-old seedlings were transplanted at 20- × 15-cm spacing and fertilized with 100-2241 kg NPK/ha. Irrigation treatments were scheduled immediately after transplanting. Water use efficiency was calculated on the basis of pooled means.

In all 3 yr, irrigation level significantly influenced yield (see table). Irrigation at 12 mm cumulative pan evaporation (CPE) with 60 mm depth produced significantly higher grain yield (5.5 t/ha) than with 36 mm CPE with 60 mm depth and 12 mm CPE with 120 mm

depth. It produced yield equal to 24 mm CPE with 60 mm depth and 24 and 36 mm CPE with 120 mm depth.

Water use efficiency was highest (4.6 kg/ha.mm) with irrigation at 36 mm CPE with 60 mm depth. The

quantity of water required was 960 mm from transplanting to maturity. Irrigation at 12 mm CPE with 60 mm depth and 24 mm CPE with 60 mm depth resulted in equal yields, but 24 mm CPE saved 960 mm of water.

Control of rice root nematode by carbofuran in Orissa, India, 1983-84. a

Nematode population/ 200 cc soil

Population/ Flowering Treatment Before g root tillers (no.)

1983 1984 1983 1984 transplanting At harvest

1983 1984 1983 1984

Fresh root weight at harvest (G)

1983 1984

Yield/plot (kg)

1983 1984

T 134.6 119.4 250.2 315.2 7.20 6.20 3.48 4.80 25.30 18.44 2.2 2.7

T3 134.4 109.6 69.0 90.0 2.66 3.20 4.56 6.60 34.64 26.70 3.0 3.3 T4 122.4 126.0 14.0 22.6 0.84 1.40 5.26 7.40 40.74 31.82 4.0 4.4

CD (0.05) 15.0 20.4 14.6 18.8 0.40 1.32 1.38 1.35 2.95 1.85 0.2 0.2 a Mean of 5 replications

T2 132.0 124.8 140.0 151.0 4.16 4.00 4.10 6.20 29.28 20.70 2.6 2.9

Irrigation Water Management

Rice yield as influenced by irrigation. Maharashtra, India, 1983-86 dry seasons.

Grain yield (t/ha) Water use Irrigation Water Irrigation a efficiency applications applied

1983-84 1984-85 1985-86 Mean (kg/ha • mm) (no.) (mm)

As required to maintain 5.5 6.6 4.3 4.8 1.7 84 2815 saturation 12 mm CPE with 5.1 6.4 5.0 5.5 2.3 40 2400 60 mm depth

24 mm CPE with 4.7 6.7 4.4 5.3 3.7 24 1440 60 mm depth 36 mm CPE with 3.4 6.0 4.0 4.5 4.6 16 60 mm depth

960

12 mm CPE with 4.2 5.1 3.6 4.3 0.9 40 4800 120 mm depth 24 mm CPE with 4.3 6.1 3.7 4.9 1.7 24 2880 120 mm depth 36 mm CPE with 3.8 6.9 3.9 4.9 2.5 16 1920 120 mm depth

CD (0.05) 0.4 1 .0 0.6 0.6

a CPE = Cumulative pan evaporation.

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40 IRRN 12:3 (June 1987)

Mollisol productivity under two management levels

A.K. Khatri, Oriental Bank of Commerce, Gorakhpur, U.P., India; and A.K. Sharma, Soil Science Department, G.B. Pant University of Agriculture and Technology, Pantnagar, U. P., India

We studied the productivity of a Mollisol occupying the lowest position on a 0-1% slope and developed on fine silty calcareous alluvial parent material. The profile was poorly drained. Surface and subsurface texture was clay loam, subsoil texture varied from silt loam to silty clay loam (Table 1). The soil was classified as fine silty, mixed, hyperthermic Typic Haplaquoll. It belongs to the Phoolbagh series.

A crop management experiment was conducted on this soil during the 1983 rainy season. High and moderate management levels were applied in a randomized block design with four replications.

High management approximated the practices followed by affluent and progressive farmers of the area. It included summer plowing, harrowing, and leveling; optimum transplanting (around 15 Jul), maintaining 3-5 cm water level in the field: 120 kg N and

Soil and Crop Management

Table 1. Physical and chemical properties of soil at Pantnagar, India, 1983.

Organic CaCO3 Cation exchange Base

(%) (%) (meq/100 g) (%)

Ap 0-11 44 24 32 7.8 3.2 0.4 25.2 91 A 1 11-31 43 21 36 7.9 2.6 0.7 24.6 91 A 3 31-48 45 31 24 8.0 2.0 0.7 19.1 100 B 2 48-10 42 37 21 8.0 1.5 2.1 17.6 95

Horizon Depth Sand Silt Clay pH matter equivalent capacity saturation (cm) (%) (%) (%)

IIB 3 70-90 25 36 39 8.1 1.4 2.5 13.5 100 IIC 90-96+ 24 41 35 8.1 1.2 2.6 13.2 98

Table 2. Yield components and yield, and net income a under 2 management levels. Pantnagar, India, 1983.

Tillers/ Grain Straw Harvest Gross Production Net Management level meter yield yield index income

(no.) (t/ha) (t/ha) ($) cost ($)

income ($)

High 64 5.9 7.9 43 786.83 315.31 411.52 Moderate 53 b 5.0 b 6.3 44 664.87 229.95 434.92

a US$l = Indian rupees 10.50 (Nov 1983). b Significant difference at 5% level. ~~

40 kg P/ha; and weeding at 20, 40, and doses and P as single superphosphate as 60 d after transplanting. a basal dose. Diseases and pests were

combination of practices followed by a Number of tillers and grain yield were farmer with moderate resources and significantly higher under high level of know-how. It included summer plowing, management (Table 2). The significant harrowing, and leveling; late increase in grain yield was due to more transplanting around 21 Jul, effective tillers per unit area. maintaining field moisture at saturation; But net income was somewhat lower 60 kg N and 20 kg P/ha; and weeding at under high management level because of 20 and 40 d after transplanting. increased costs of production.

Moderate management was a controlled as needed.

N was applied as urea in three split

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Effect of nitrogen source and insect control on growth of a ratoon crop

K. S. Prakash and B. G. Prakash, Agricultural Research Station, Siruguppa 583121, India

We studied N source and insecticide treatment on a ratoon crop (Sona Mahsuri) in 1985-86. The area has endemic brown planthopper Nilaparvata lugens that could survive in the stubble of a ratoon crop. There were 4 fertilizer treatments: 0 N/ha, 50 kg N/ha, azolla

monocrotophos at 0.5 kg ai/ha and chlorpyrifos at 0.3 kg ai/ ha. Treatments were laid out in a randomized complete block design with three replications.

Azolla (fresh weight) was applied on the soil surface 3-4 times, up to 12 t/ha. But the azolla could not be uniformly maintained in the field. Growth and multiplication were retarded by fluctuating water level, snail damage, and high temperature. Soil salinity also could have affected azolla growth. Soils were black deep Vertisols with pH 8.5.

applied 34 times at 2.5 t/ha, and azolla N content of the azolla was about 6%. + 25 kg N/ha. The insecticides were Regenerated tillers were counted at 15

IRRN 12:3 (June 1987) 41

Information on release of nutrients other than N by green manures is scarce.

We studied the effect of Sesbania straw on Eh-pH kinetics and the release of water-soluble nutrients in a flooded rice soil in the laboratory.

The Crowley silt 1oam (Typic Albaqualf) collected from the Rice Experimental Station at Crowley, Louisiana, had pH 6.7,0.81% organic C, and CEC 14.8 meq/ 100 g.

To monitor changes in Eh and pH, duplicate 60-g samples of air-dry soil, without or with 0.2% by weight sesbania

straw (2.5% N) were transferred into redox tubes. The tubes were constructed by sealing 12.5 mm of 18-gauge platinum wire on both sides of 40 × 138 mm pyrex test tubes, 25 mm from the bottom. The soil samples were submerged with an excess of deionized distilled water and incubated at 30 °C. pH and Eh measurements were made at intervals for 60 d.

To monitor release of water-soluble nutrients, duplicate 10-g portions of air-

C.S. Khind, A. Jugsujinda, C.W. Lindau, and W.H. Patrick, Jr., Laboratory for Wetland Soils and Sediments, Louisiana State University, Baton Rouge, Louisiana 70803-7511, USA

Effect of N source and insecticide treatment on ratoon crop. Siruguppa, India, 1985-86.

Treatment a Regenerated Plant Tillers/ Panicles/ Sterility Yield Harvest tillers height plant plant (no.) (cm) (%) (t/ha) index

No N (control) 11 43.9 13 10 2.15 0.9 0.44 No N + monocrotophos 9 47.7 11 8 4.72 0.9 0.49 No N + chlorpyrifos 13 49.0 15 12 50 kg N/ha

2.71 1.2 0.49 22 63.9 20 21 2.11 2.2 0.44

50 kg N/ha + 22 64.3 26 20 1.25 1.9 0.41

50 kg N/ha + 18 60.0 24 17 0.93 1.9 0.44

Azolla 14 50.4 17 13 2.7 1.7 0.50 Azolla + monocrotophos 13 48.8 14 11 1.3 1.2 0.41 Azolla + chlorpyrifos 15 48.3 13 11 1.5 0.7 0.40 Azolla + 25 kg N/ha 18 56.6 21 17 1.3 2.0 0.52 Azolla + 25 kg N/ha + 21 53.3 24 14 1.8 1.5 0.45

Azolla + 25 kg N/ha + 23 56.8 20 18 1.2 1.4 0.45

CD (0.05) 4.26 7.80 0.98 9.4 0.52 0.74 0.09

monocrotophos

chlorpyrifos

monocrotophos

chlorpyrifos

a Monocrotophos at 0.5 kg ai/ha, chlorpyrifos at 0.3 kg ai/ha, and azolla at 2.5 t/ha.

Effect of sesbania straw in a flooded soil on soil pH, redox potential, and water-soluble nutrients

d after ratooning; plant height, tillers per plant, panicles per plant, sterility percentage, yield, and harvest index were noted at harvest (see table). Number of regenerated tillers, panicles/ plant, and yield vaned considerably. In most treatments, some tillers regenerated after 15 d.

The interaction between N source and insecticide application had no significant effect on ratoon growth and development because there was no pest pressure on either the main or the ratoon crops. Fertilizer at 50 kg N/ ha gave the highest mean ratoon yield. Applying azolla immediately after ratooning may not benefit the ratoon crop because azolla N is not available to the plant until the azolla decomposes.

1. Effect of sesbania straw on kinetics of pH and Eh in a flooded Crowley silt loam soil in the laboratory. Louisiana State University, 1987.

42 IRRN 12:3 (June 1987)

2. Effect of sesbania straw on water-soluble nutrients in a flooded Crowley silt loam soil in the laboratory. Louisiana State University, 1987.

dry soil, with and without sesbania straw, were transferred into 50-ml centrifuge tubes (25 × 100 ml) fitted with rubber septa. The soil samples were submerged with 25 ml of deionized distilled water. The tubes were weighed and incubated at 30°C. Moisture lost during incubation was replaced by weighing the tubes occasionally and adding water as needed.

shaken for 30 min, centrifuged at 7,000 rev/min for 20 min, and the solutions filtered through 0.45-µm filter paper. The samples were acidified to pH 2 with 12 N HCl and analyzed for different elements on an Inductive Coupled Argon Plasma emission spectrophotometer.

Decreases in soil Eh after flooding were more pronounced with the addition of sesbania straw (Fig. 1). At 60 d after flooding (DF), soil Eh decreased to -125 without sesbania and to -245 mV with sesbania. The Eh of the soil receiving sesbania stabilized at

At specified intervals, the tubes were

30 DF, the Eh in unamended samples stabilized at 40 DF.

Increased soil reduction caused by incorporation of sesbania straw was also reflected by increases in soil pH. At 60 DF, soil pH increased from 6.8 to 7.2 without sesbania and to 7.4 with sesbania.

Incorporation of sesbania straw had a

Amelioration of highly alkali soil by karnal grass and para grass before rice - wheat cropping sequence

A. Kumar, Central Soil Salinity Research Institute, Karnal 132001, Haryana, India

To reclaim alkali soils (pH greater than l0), 12-15 t gypsum/ha followed by rice - wheat for 3-4 yr has been recommended. But gypsum is costly for small and marginal farmers.

[ Diplachne fusca (Linn.) P. Beauv] and We studied growing karnal grass

variable effect on the release of water- soluble nutrients in the flooded soil (Fig. 2). Sesbania application caused marked increases of water-soluble Ca, Mg, P, Fe, and Mn. Those increases peaked 4 to 8 DF, then decreased. Sesbania straw had a slightly depressing effect on water-soluble Cu, Zn, and Al, but had no effect on water-soluble Si.

para grass [ Brachiaria mutica (Forsk.) Stapf.] as alternatives to gypsum.

and exchangeable sodium percentage (ESP) 94. Soil texture was sandy loam with 15% clay, 27% silt, and 58% sand. The experiment was conducted 1979-80 to 1983-84 in a split-plot design with four replications. The eight treatments are in the table.

Jaya rice and HD2009 wheat were sown throughout. Gypsum was applied 19 Jun 1979. Karnal grass and para grass were planted 8 Jul 1979.

The field was highly alkaline: pH 10.6

IRRN 12:3 (June 1987) 43

Recommended agronomic practices for growing rice and wheat in alkali soil were followed.

The results indicate that grasses grown for 2 yr sufficiently ameliorated the soil for a successful rice -wheat sequence. Rice yields in plots without amendment were possible the third year, and wheat yields the fourth year. Yields of rice and wheat in plots where 12.5 t gypsum/ha was applied and where karnal grass was grown for 2 yr did not differ significantly.

Changes of soil pH as a result of the treatments are shown in the figure. The pH reduction was greatest in plots

Rice - wheat yields in alkali soil treated with gypsum or grass crops. Haryana, India, 1979-84.

Yield (t/ha)

1979-80 1980-81 1981-82 1982-83 1983-84

Rice Wheat Rice Wheat Rice Wheat Rice Wheat Rice Wheat Treatment a

No amendment 0 0 1.0 0 4.6 0.6 5.7 2.7 5.1 3.8 Gypsum 3.7 2.6 4.5 1.3 5.8 3.4 6.5 3.6 4.8 4.6 P 1 yr – – 3.8 0.1 5.8 1.6 6.8 3.3 5.4 4.7 P 2 yr – – – – 5.3 2.6 5.9 3.4 5.1 4.9 P 3 yr – – – – – – 5.6 3.0 5.9 4.3 K 1 yr – – 4.1 0.3 5.4 2.1 6.6 3.6 5.4 4.6 K 2 yr – – – – 6. 1 3.4 5.8 3.8 5.2 5.2 K 3 yr – – – – – – 5.8 3.2 5.5 4.1

CD (0.05) – – – – – – ns 0.5 0.5 0.6

a P = para grass, K = karnal grass.

where gypsum was applied. For the plots where karnal grass was grown for grasses, pH reduction was greater in 2 yr.

Soil reduction over 5 yr in response to gypsum and grass- es amendments. 1 = initial pH in 1979; 2 = pH in 1980 before rice; 3, 4, and 5 = pH in 1981, 1982, and 1983 after rice.

Effect of pyrite and fertilizer on rice protein quality

S. K. Addy, A. Singh, R. Singh, and C. P. Awasthi, Soil Science Department, Narendra Deva University of Agriculture and Technology, Narendra Nagar (Kumarganj), Faizabad 224229 (U. P.), India

Protein concentration in grain increases with high fertility. Because the poor biological value of rice protein is

attributed to the deficiency of essential amino acids, such as lysine and tryptophan, we studied the effect of different levels of pyrite and fertilizer on protein quality of rice.

The soil was slightly saline-alkali with moderate pH and exchangeable sodium percentage. Pyrite was applied 10 d before transplanting Saket 4 to ensure complete oxidation in the experimental field. N as urea, single superphosphate, and muriate of potash were applied.

Half the N and all the P and potash were applied at transplanting. The remaining N was applied 30 d after transplanting.

sickle and dried in an oven at 60 °C. The samples were hand pounded to brown rice, ground to powder, and passed through a 60-mesh sieve for chemical analysis. N content in the defatted samples was determined by microKjeldahl method; that value was

Grain samples were harvested with a

44 IRRN 12:3 (June 1987)

multiplied by a factor of 5.95 to get protein content. Protein fractions were estimated on the basis of solubility in water (albumin), sodium chloride (globulin), ethyl alcohol (prolamin), and sodium hydroxide (glutelin). Lysine content was measured using trinitrobenzene sulfonic acid reagent. Protein fractions and lysine content were calculated as percent of grain.

Protein content increased in all treatments. The highest protein content was obtained with 600 kg pyrite/ha and 120-60-60 kg NPK/ha.

Fractionation revealed that the major

amount of protein was in the form of glutelin (6.65%) (see table). Higher fertility slightly increased the prolamin and glutelin fractions. Lysine content

decreased with increased pyrite and NPK. Protein content was positively correlated with prolamin and glutelin and negatively correlated with lysine.

Effect of pyrite and fertilizers on brown rice protein quality. Faizabad, India, 1985–86 kharif.

0.53–0.74 Globulin 0.55–0.77 0.69 0.09

0.76** Protein vs glutelin Prolamin 0.32–0.65 0.51 0.14 Protein vs prolamin 0.55*

Glutelin 6.09–7.13 6.65 0.50 Prolamin vs glutelin 0.65** Lysine 0.22–0.30 0.26 0.04 Protein vs lysine –0.81**

Character Range Mean CD at 5% Character Coefficient (%) of correlation a

8.00–9.00 8.58 0.40 Protein vs albumin –0.46 0.62 0.07 Protein vs globulin –0.32

a * = significant at 5%, ** = significant at 1%.

Response to nitrogen of rice in sodic soil

K. N. Singh and D. K. Sharma, Central Soil Salinity Research Institute, Kurnal 132001, India

We studied the influence of N level (0, 60, 120, and 180 kg/ ha) on yield in highly barren sodic soil without amendment. Soil was sandy loam with pH 10.3, 90% exchangeable sodium, 0.35 meq exchangeable Ca + Mg/ 100 g, 30 kg available N/ ha, 21 ppm Olsen's

extractable P, and adequate available K in the 0–15 cm layer.

transplanted 16 Jul 1981 and 1982. Zinc sulfate at 5.5 kg/ ha with one-third N as urea was applied at transplanting, with 1/3 N at 25 and 1/3 N at 50 d after transplanting. The crop was harvested 17 Nov 1981 and 16 Nov 1982.

Grain and straw yields increased significantly with N level (Table 1). The N content of grain and straw also increased (Table 2).

Damoder (CSR-1) variety was

Table 2. N content ingrain and straw by N level. Karnal, India, 1981–82.

N content (%) N level

(kg/ha) 1981 1982

Grain Straw Grain Straw

0 1.08 0.28 1.00 0.33 60 1.22 0.30 1.04 0.44

120 1.33 0.33 1.13 0.47 180 1.44 0.35 1.30 0.53 CD (0.05) 0.10 0.04 0.08 0.05

Table 1. Effect of N level on yield and yield attributes. Karnal, India, 1981–82.

1981 1982 pH at N level 0–15 cm

ht tillers/hill length ht tillers/hill length in 1982 (kg/ha) Plant Productive Panicle Yield (t/ha) Plant Productive Panicle Yield (t/ha) after harvest

(cm) (cm) Grain Straw (cm) (cm) Grain Straw

0 83.4 7.8 14.4 1.3 2.4 98.7 6.1 14.9 1.4 2.3 9.8 60 95.1 11.5 15.6 2.2 3.7 113.0 10.9 17.3 2.5 4.2 9.8

120 105.5 13.1 16.4 2.9 4.9 117.9 12.5 17.7 3.0 5.3 9.7 180 111.0 14.5 17.0 3.6 5.9 124.8 13.8 18.5 3.4 5.9 9.7

CD (0.05) 6.5 0.9 0.8 0.4 0.6 7.2 1.1 0.7 0.4 0.6 –

Comparative efficiency of puddling implements

S. T. Thorat, R. G. Joshi, M. T. Deshmukh, and S.B. Kadrekar. Konkan Agricultural University, Dapoli 415712, Maharashtra, India

We evaluated the performance of different puddling implements — rotary power tiller, iron puddler, iron plow,

country wooden plow, and wooden puddler — during the 1982–84 monsoon seasons and their effect on yield in newly terraced land.

The experiment was in a randomized block design with five replications. All implements except the rotary power tiller were bullock drawn. The plots were puddled with two criss-cross passes except with the country wooden plow, which had the farmer practice of four

passes. Plot size was 9.6 × 4.2 m. Soil was clay loam, lateritic with pH 5.6 and 1. 19% organic C.

After puddling, Jaya was transplanted in early Jul at 20- × 15-cm spacing. The crop was fertilized with 100-22-41 kg NPK/ha. All the P and K and 40% N were applied at transplanting. The remaining N was applied in two equal splits at tillering and panicle initiation.

In 1983, yield was significantly

IRRN 12:3 (June 1987) 45

Protein Albumin

55, and 65 d old) as subplot treatments. There were four replications. The crop was fertilized with 100 kg N and 22 kg P/ha. All the P and half the N were basally applied at transplanting, the

Assured canal irrigation and improved marketing have led to dry season rice cultivation in South Gujarat. Information is needed on optimum seeding date and seedling age at transplanting for summer cultivation of long-duration variety Mahsuri.

We conducted a field experiment on the college farm during 1981-82 and 1982-83 summer seasons. The split-plot design had 4 seeding dates (1 Nov, 15 Nov, 30 Nov, and 15 Dec) as main

C.L. Patel, Z. G. Patel, I. G. Patel, and A. G. Naik, Agronomy Department, Gujarat Agricultural University, Navsari, India

influenced by puddling treatment (see table). Plots puddled with the rotary power tiller and the iron puddler had significantly higher yields than those puddled with the iron plow and the wooden puddler. Yields with the rotary power tiller, iron puddler, and country wooden plow and with the wooden plow, the iron plow, and the wooden puddler were similar. Yields with all implements increased across the 3 yr.

Effect of puddling implement on rice grain yield. Maharashtra, India, 1982-84.

Grain yield (t/ha)

Rotary Iron Iron Country Wooden power puddler plow wooden puddler

Year CD (0.05)

tiller plow

1982 2.2 2.3 2.0 2.0 2.4 ns 1983 1984

3.5 3.4 2.7 2.8 2.4 0.48 5.0 4.7 4.5 5.0 4.5 ns

Pooled mean 3.6 3.5 3 .0 3.3 3.1 0.34

Effect of sodicity and pretransplanting submergence on rice yield

A. Swarup, Central Soil Salinity Research Institute, Karnal 132001, India

We evaluated the effect on yield of four percentages of exchangeable sodium (ESP) and length of pretransplanting submergence. The split-plot design had ESP levels in the main plots and pretransplanting submergence in the subplots, with four replications. Subplot was 40 m2. Urea at 150 kg N/ ha and 9 kg Zn/ ha were applied: half the N and all the Zn at transplanting and half the N topdressed in 2 equal splits at 3 and 6 wk after transplanting. The crop was harvested 1 Nov 1982.

Presubmergence for 15 and 30 d increased yields (see figure). This effect was more pronounced at high ESP. The mean yield increase due to 15 d

Change in soil pH, ESP, and exchangeable Ca + Mg after rice harvest. Karnal, India, 1982.

Before rice After rice

Soil no. ESP pH Exchangeable ESP pH Exchangeable Ca + Mg

(meq/l00 g) Ca + Mg

(meq/100 g)

1 82 10.2 1.4 70 2 72

9.8 9.9

2.1

3 2.1 58 9.5

65 3.1

9.7 2.8 47 9.4 3.8 4 35 9.3 5.2 25 9.0 6.0

submergence was 0.5 t/ha and that to 30 d submergence, 0.9 t/ha.

The effect was beneficial because these sodic soils undergo reduction in pH and redox potential, increase in partial pressure of CO 2 (PCO 2 ), and change in other physicochemical characteristics within 2 wk of flooding. This creates a favorable ionic

environment in the rhizosphere. Seedlings transplanted immediately

after flooding (0 day presubmergence) showed stunted growth and lower yields because of initially high pH and ESP and reduced availability of nutrients. ESP and pH of the soils decreased substantially after rice under flooded conditions (see table).

Effect of seeding date and seedling age on dry season yield

Interaction effect of seeding date and seedling age at transplanting on grain yield of Mahsuri rice. a Gujarat, India, 1981-82, 1982-1983 summer seasons.

Seeding date

Grain yield (t/ha) by seedling age

45 d 55 d 65 d 1 Nov 3.7 3.9 4.2 15 Nov 3.9 4.4 4.1 30 Nov 5.3 6.2 3.9 15 Dec 4.4 4.1 3.3

CD (0.05) 0.2 Effect of sodicity and pretransplanting sub- mergence on rice yield. Karnal, India, 1982. plot treatments and 3 seedling ages (45, a Pooled data for 2 summer seasons.

46 IRRN 12:3 (June 1987)

With traditional ratooning techniques, yields are low, 20-30% of the main crop yield. Lack of adequate leaf area may be a factor in the lower ratoon yields. We tried using mother leaves for the ratoon

remaining N was topdressed in two 55-d-old seedlings (see table). The lowest seeding gave higher yields with younger equal splits at tillering and at panicle yield (3.3 t/ha) was with seeding on seedlings. Low temperature during early initiation. Two seedlings/hill were 15 Dec and transplanting 65-d-old seeding dates restricted seedling growth. transplanted at 25- × 15-cm spacing. seedlings. Transplanting young seedlings during

with 30 Nov seeding and transplanting yields with older seedlings and late establishment. The highest grain yield (6.2 t/ha) was In general, early seeding gave higher cold days hindered crop

Scarifying seeds of green manure legumes

C. Rarivoson, Plant Biology and Biochemistry Department, University of Madagascar, Antananarivo, Madagascar; M. Schramm, Biology Department, Humboldt - University of Berlin, GDR; Ch. Samson, Mission IRAT, Madagascar; and Fetiarson, Agronomic Research Department, FOFIFA, Antananarivo, Madagascar

The hard seededness characteristic of green manure legume seeds often

prevents germination, leading to poor stands. We studied scarification methods appropriate for a low technology production program.

Seeds of Aeschynomena uniflora, A. schimperii, A. sensitiva, Sesbania rostrata, and an unidentified Sesbania species were harvested in Jun. In Oct, 3 scarification methods were applied: concentrated H 2 SO 4 from 0 to 180 min, boiling water from 0 to 90 min, and abrasion with sand. Seeds (20/ treatment replicated twice) were germinated on moist filter paper at 30 °C.

Acid and mechanical abrasion

2. Germination of green manure by legume seeds scarified by abrasion with sand. Madagascar, 1986.

methods of scarification were effective, but boiling water was not. Germination of H 2 SO 4 -treated seed varied by species (Fig. 1). The highest germination of sesbania was achieved with seeds soaked in H 2 SO 4 for 2 h.

Mechanical abrasion was effective for A. uniflora but not for A. schimperii or A. sensitiva. Mechanical abrasion of sesbania seeds increased germination 45% (Fig. 2).

Whole-plant ratooning technique

D.M. Maurya, D.N. Vishwakarma, and S. P.S. Rathi, Narendra Deva University of Agriculture and Technology, Narendranagar, Faizabad, (U.P.), India

1. Germination of green manure legume seeds by time of scarification with concentra- ted H 2 SO 4 . Madagascar, 1986.

IRRN 12:3 (June 1987) 47

Yield and yield components in main and full plant ratoon crops. Faizabad, India, 1986.

Variety Duration (d)

NDR119 94 NDR1001 90 NDR118 96 NDR102 95 NDR312 97

CD (0.05)

Tillers/ plant

18 17 16 17 18

Main

Effective Grains/ tillers/ panicle plant

16 86 16 88 15 94 14 92 15 91

1000- Yield grain (t/ha)

wt (g)

16.5 3.0 16.0 3.2 18.0 3.6 17.5 3.7 17.8 3.6

0.7

Duration (d)

33 36 35 34 36

Ratoon crop Total

Effective Grains/ 1000- Yield Duration Yield tillers/ panicle grain (t/ha) (d) (t/ha) plant wt (g)

15 14

81.0 16.2 2.4 127 5.4

14 83.0 15.8 2.7 126 5.8

16 90.0 17.7 2.0 131 5.6

15 89.0 17.2 2.1 129 5.8 85.0 17.6 2.1 133 5.6

0.6

crop by harvesting only panicles, leaving the leaves and stem intact. New shoots arose from higher nodes, instead of the ground tillers as in traditional ratooning. The number of branches emerging from each tiller and total tillers approached the number in the main crop, and in some plants even exceeded it.

Each branch developed 2-3 small

leaves. Panicle size almost matched that of the main crop. The ratoon crop matured in 34-36 d, with yield levels approaching 80-85% of the main crop (see table).

The experiment was conducted with very short-duration varieties. The nursery was sown on 19 Jun 1986, 25-d- old seedlings were transplanted at

1 seedling/ hill in 12- × 5-m plots with 20- × 15-cm spacing and 60-30-30 kg NPK/ha. The ratoon crop was fertilized with 30-75 kg NP/ha.

Yields of the different varieties were similar. This technique costs more because of the need for hand sickle harvesting of the main crop without disturbing the shoot system.

Effect of phosphates on flooded rice

Badrinath, A.M. Krishnappa, B.N. Patil, N.A.J. Gowda, P.S. Herle, and K.B. Rao, Agricultural Research Station, Mangalore 575002, India

We evaluated superphosphate (SP), Mussoorie rock phosphate (MRP), and Mussoorie rock phosphate plus

Effect of P source and level on rice yield. Mangalore, India, 1984-86.

Grain yield (t/ha) Treatment

1984-85 1985-86

Main plot Control 3.3 3.1 SP 3.9 MRP

3.5 3.3

MRP + SP (75 + 25) 3.5 3.1 3.2

MRP + SP (50 + 50) 3.6 3.2 MRP + SP (25 + 75) 3.8 3.4 DAP 3.9 3.5

F test SEm ± 0.12 0.06 CD (0.05) 0.3 0.2

0 kg P/ha 3.3 3.0 13.2 kg P/ha 3.6 3.3 26.4 kg P/ha 3.8 3.4 39.6 kg P/ha 3.8 3.3

* *

Subplot

F test ns 0.01 SEm ± 0.14 0.04 CD (0.05) ns 0.1 Interaction ns Significant

48 IRRN 12:3 (June 1987)

superphosphate (MRP + SP) and diammonium phosphate (DAP) in the midland soils of coastal Karnataka during the 1984 and 1985 wet seasons.

Ustoxtropept with pH 5.0, electrical conductivity 0.2 dS/m at 25 °C, 1.26% organic C, 56 kg P/ha, and 83 kg K/ha. Available micronutrients (in ppm) were Zn 0.25, Cu 1.86, Mn 0.38, Fe 57.7, and B 0.50. The experiment was in a split- plot design with P sources in main plots and P levels in subplots, including a no- P control.

Three 27-d-old IET2911 (medium duration) seedlings/ hill were transplanted at 15- ×15-cm spacing. All plots received 100 kg N and 88 kg K/ha.

Soil was sandy clay loam,

Effect of basally applied coated urea on grain yield

P. Balasubramanian, A.S. Dawood, and S. Sankaran, Tamil Nadu Rice Research Institute (TRRI), Aduthurai 612101, India

In Cauvery Delta, farmers usually apply N as urea in split doses. But with monsoon weather, water stagnation in the field, and social factors, N often is not applied on time.

Half the N was applied at transplanting, 25% at tillering, and 25% at panicle initiation. P was applied at transplanting.

transplanting to maturity and the crop protected from insects, diseases, and weeds.

Fertilizer sources gave significantly different yields in both years (see table). The higher yield with SP alone or DAP were comparable to that with MRP + SP (25% + 75%).

significantly higher than with other levels. The interaction effects were also significant in 1985-86. Locally available MRP is an inexpensive source of P.

The field was flooded from

Yield with 26.4 kg P/ha was

We compared N applied in a single basal dose as coal-tar-coated urea (CCU), neem-coated urea (NCU), sulfur-coated urea (SCU), and urea supergranules (USG), to N applied in 3 splits (50% basal, 25% at tillering, and 25% at panicle initiation) as prilled urea

Two experiments were conducted Jun-Sep 1983 and 1984 using short- duration rice varieties (110-115 d) in a randomized block design with four

(PU).

replications. Soil was clay loam, with low available N, medium available P and K, and pH 7.5.

Basal CCU (1%) and NCU (5%)

Applying nitrogen with sesbania

Y. Singh, B. Singh, M.S. Maskina, and C.S. Khind, Soils Department, Punjab Agricultural University, Ludhiana 141004, India

Yields with and without sesbania green manure and three levels of N as urea in different splits were studied in a field experiment laid out in a randomized complete block design with four replications during 1986 kharif. Soil was a sandy loam (Typic Ustochrept) with pH 8.2, EC 0.15 dS/m, organic C 0.34%, total N 0.06% Olsen’s P 10 kg/ha, and a percolation rate of 5 mm/h.

Sesbania grown in situ for 7 wk was incorporated 1 d before transplanting. Sesbania dry matter was 24 t/ha, with

Responses of rice to N, P, and Zn in semireclaimed alkali soil

M. V. Singh, Central Soil Salinity Research Institute, Karnal 132001, India

P deficiency has been a major cause of low yields in semireclaimed alkali soils. We studied the effect of P fertilization with N and Zn in a semireclaimed alkali

Effect of P application with N and Zn on yield in a semireclaimed alkali soil. Karnal, India.

Treatment Grain yield (t/ha)

(kg/ha) Zero 17.5 kg P Mean

N 120 Z 0 4.9 5.2 5.0 N 160 Z 0 5.2 5.3 5.2 N 80 Z 20 4.5 5.0 4.8 N 120 Z 20 5.4 6.6 6 .0 N 160 Z 20 5.8 7.5 6.6 N 200 Z 20 5.7 7.1 6.4

Mean 5.2 6.1 LSD (0.05)

N 0.72 P 0.36 N × P ns

yields were not significantly different were not significantly different from that from that with PU in splits. with split applications of PU.

deep point placed 2 d after transplanting expensive practice. Yields with SCU broadcast and USG Split-applied urea was the least

Sesbania plus N effects on yield. Ludhiana, India, 1986 kharif.

N application (kg/ha) at indicated time Grain Treatment yield

0 DT 21 DT 42 DT (t/ha)

No sesbania + no N No sesbania + 120 kg N/ha No sesbania + 180 kg N/ha Sesbania + no N Sesbania + 60 kg N/ha Sesbania + 60 kg N/ha Sesbania + 60 kg N/ha Sesbania + 60 kg N/ha Sesbania + 60 kg N/ha Sesbania + 120 kg N/ha Sesbania + 120 kg N/ha

40 60

60

30 30

–

–

–

– –

40

LSD (P = 0.05)

106 kg N/ ha. All plots received 26 kg P and 23 kg K/ha at the final puddling. Sesbania green manure plus 60 kg N/ha yielded more than sesbania with 120 kg N/ha (see table). Applying 60 kg N/ha

40 60

–

–

60

30 30 60 40

–

–

40 60

–

– –

30

30 60 40

–

–

4.8 7.4 8.2 7.0 8.1 7.8 8.1 7.7 8.4 8.4 9.0 0.4

in 2 equal splits at 21 d and 42 d after transplanting (DT) was most efficient.

If 120 kg N/ha is applied with green manure, 3 equal splits at 0, 21, and 42 DT gave the highest yield.

soil. The experiment was laid out in a split-plot design with four replications.

applied at transplanting as urea, single superphosphate, and zinc sulfate. The remaining N was topdressed in 2 equal splits at 3 and 6 wk after transplanting. Recommended agronomic practices were followed.

sodic (pH 10.45), but gypsum application and 4 yr cropping had reduced pH to 8.8, EC to 0.42 dS/m,

Half the N and all the P and Zn were

Originally the soil had been highly

and exchangeable sodium percentage to 19 in 0-15 cm surface soil. The soil had loamy texture, 0.28% organic C, 2.73% CaCO 3 , 0.5 mg DTPA-Zn/kg, 76 mg available N, 3.96 mg available P, and 140 mg available K/kg.

Applying N and Zn without P had no effect on yield. Applying N, P, and Zn together significantly increased yield (see table). A balanced application of 160 kg N, 17.5 kg P, and 4.5 kg Zn/ha gave the maximum yield.

Effects of several urea-based N sources

B. Jena and C. Misra, Orissa University of Agriculture and Technology, Bhubaneswar 75 1003, India

We compared 6 urea sources — prilled urea (PU), urea supergranule (USG), large granule urea (LGU), neem cake- coated urea (NCU), rock phosphate-

coated urea (RPU), and sulfur-coated urea (SCU) — at 37.5, 112.5, and 150 kg N/ ha in a 1986 dry season field experiment. Soil was a fine loamy hyperthermic Typic Haplaquept with pH 5.3, organic C 0.46%, CEC 4.3 meq/ 100 g, 215 kg available N/ ha (alk. permanganate method), 6.5 kg available P/ ha (NaHCO 3 extract), and 37 kg available K/ ha (ammonium acetate extract). The experiment was in a split-

IRRN 12:3 (June 1987) 49

plot design with N in the main plots and Table 1. Grain yield with urea-based N sources. Bhubaneswar, India, 1986 dry season.

sources in the subplots.

677/IR2071//Vikram/W1263, 130 d duration group) were transplanted on 22 Jan. All plots received 22 kg P and 41 kg K/ha with all the LGU, NCU, RPU, SCU, and 1/3 the PU at transplanting. All the USG was placed 7 cm deep at 10 d after transplanting (DT). The additional PU was applied in equal splits at 20 DT and at panicle initiation.

Yields increased significantly with increasing N up to 112.5 kg N/ha (Table l), although yield response (kg grain/ kg N) and apparent N recovery values (Table 2) were highest at 37.5 kg N. Yields with USG and SCU were equal and significantly superior to those with other N sources. USG at 75 kg N/ha was the best treatment, as is reflected in yield response and apparent N recovery.

Seedlings of Lalat (Obs Nitrogen dose Yield (t/ha)

(kg/ha) PU USG LGU NCU RPU SCU Mean

0 2.2 2.1 2.2 2.3 2.1 37.5 3.4 3.5 3.9 3.9 3.7

2.4 4.3

2.2

75.0 4.5 5.5 4.4 4.3 3.9 5.0 3.8

112.5 5.5 5.5 4.7 5.1 5.3 4.6

150.0 6.2

5.6 5.4

5.5 5.5 5.5 5.3 5.5 5.5 Mean 4.2 4.6 4.0 4.2 4.1 4.5 4.3 LSD (0.05) N:0.6, Source: 0.3. Sources at fixed N: 0.7 and N at the same or different

source: 0.9

Table 2. Yield response and apparent N recovery with urea-based N sources. Bhubaneswar, India, 1986 dry season.

Nitrogen dose Yield Apparent Yield Apparent

(kg/ha) response N Source response N

(kg grain/kg N) recovery (%) (kg grain/kg N) recovery (%)

37.5 41.6 51.4

112.5 USG 38.1 75.0 31.7 39.3 PU 28.0 44.7

54.2 28.0 42.7 LGU 26.6 32.6

150.0 21.7 40.2 NCU 30.1 41.9 RPU 28.6 SCU

39.5 33.1 47.5

Effect of urea supergranule (USG) on grain yield of varieties of different durations

S. V. Subbaiah and S. K. Sharma, Agronomy Department, Directorate of Rice Research, Rajendranagar, Hyderabad 500030, Andhra Pradesh, India

We studied the influence of USG on varieties of different durations in controlled irrigated experiments 1984-

Table 1. Mean grain yield of irrigated six long- duration varieties with USG and split applica- tions of prilled urea. Andhra Pradesh, India, 1984-85.

Grain yield (t/ha)

Treatment 1984 1985

Best split (prilled urea) 5.8 4.9 Four splits (prilled urea) 5.3 4.6 USG at 7 DT 5.5 5.1 1/4 N as prilled urea (basal) – 5.1

3/4 N as USG at 7 DT + – 5.3 + 3/4 N as USG at 28 DT

1/4 N as prilled urea at panicle initiation

CD (0.05) 0.3 0.2 CV (%) 7.1 6.8

85. Recommended P, K, and Zn were applied before field puddling, N was applied as per treatment. The soil was a Vertisol type with pH 8.2, CEC 49.2 meq/ 100 g soil, 0.09% total N, and 5 ppm available P.

Short-duration (95-105 d) IET7564, IET7613, IET7614, and IET7566 were evaluated with 90 kg N/ ha using USG placement and prilled urea split application. Source of N was not significant (3.94.4 t/ha).

Table 2. Effect of modified urea materials on grain yield of Rasi. Andhra Pradesh, India, 1984 kharif.

Grain Treatment yield

(t/ha)

Urea best split 4.6 USG at 7 DT 5.8 Mussoorie-phos-coated urea 4.8 Gypsum-coated urea 4.8 Neem cake-coated urea 4.4 Urea 4 equal splits (1/4 N basal + 4.5

1/4 N before panicle initiation + 1/4 N after panicle initiation + 1/4 N panicle stage)

Compost + USG (1/2 N as USG) 4.8 CD (0.05) CV (%)

0.8 9.4

In longduration (150-165 d) IET5897, IET5890, IET5656, Jagannath, Phalguna, and Pankaj, 90 kg N/ ha as urea best split was superior or equal to USG placement at 7 d after transplanting (DT). Yields with 3/4 N as USG at 7 DT + 1/4 N as prilled urea at panicle initiation were significantly greater than yields with prilled urea best split (Table 1).

Medium-duration Rasi responded better to USG (90 kg N/ha) than to prilled urea and other coated materials (Table 2).

~

Mussoorie rock phosphate (MRP) effects on yield

Badrinath, A.M. Krishnappa, P.S. Herle, B.N. Patil, N.A.J. Gowda, and K.B. Rao, Agricultural Research Station, Mangalore 575002, India

MRP is an indigenous fertilizer material suitable for acid soils; it slowly and continuously releases available P.

We studied its availability to rice variety Phalguna in a field experiment

50 IRRN 12:3 (June 1987)

conducted during kharif seasons 1983- 85. Experimental site soils are yellowish brown (10 YR 7/6 dry), clay loam, strong medium subangular blocky, dry hard, moist firm, wet sticky, moderate1y slow permeability with pH 5.7. They are high in organic C (1.26%) and available P (82 kg/ ha), but low in available K (50 kg/ ha).

Four main treatments (application at 0, 7, 14, and 21 d before transp1anting [DBT]) and 4 subtreatments (0, 13.2, 26.4, and 39.6 kg P/ha) were tested in a split-plot design. All plots received 100 kg N and 73 kg K/ha.

Net plot (5.76 m2) yields over a period of 3 yr are presented in the table. Although the yield increase with MRP applied 7 DBT was not significant, the yield difference with 26.4 kg P/ ha was significant. The interaction between P level and time of application was not significant.

Nitrogen sources and placement for irrigated rice

M.S. Zia, Pakistan Agricultural Research Council, Soil Science Section, National Agricultural Research Centre, P. O., N.I. H., Park Road, Islamabad, Pakistan

We studied N source and placement method for irrigated rice on a clay loam soil with pH 8.3 and 0.6% organic matter.

Deep placement of urea supergranules (USG) gave a higher yield and was the

most efficient, but was not significantly different from incorporating urea in dry soil (see table). Efficiency of dry soil incorporation was on a par with deep placement of USG

Incorporating urea in puddled soil gave a significantly lower yield. Calcium ammonium nitrate incorporated in puddled soil had the lowest yield after control and was the least efficient. Yields were significantly higher with higher levels of fertilizer but fertilizer efficiency was higher at lower levels.

In the Cuu Long (Mekong) Delta of Vietnam, acid-sulfate soils are found in 1.15 million ha, mostly in Kien Giang, Long An, Dong Thap, Hau Giang, and An Giang Provinces. Seedling mortality and poor crop growth due to extremely

B.K. Singh, P.S. Tan, L. V. Thanh, and N. V. Luat, Cuu Long Delta Rice Research Institute, Omon, Hau Giang, Vietnam

We observed that grass weed seedlings had been transplanted with rice

Effect of MRP on yield. Mangalore, India, 1983-85.

Yield (kg/plot)

1983 1984 1985 Treatment

Main plot Application on 3.72 0.97 1.96 day of transplanting

7 DBT 3.89 1.11 2.07 14 DBT 3.71 1.22 1.97 21 DBT 3.71 1.08 1.95

F test ns ns ns SEm ± 0.10 0.08 0.03 CV (%) 10.62 27.73 5.74

Subplot 0 kg P/ha 3.10 1.13 1.89 13.2 kg P/ha 3.77 1.11 1.97 26.4 kg P/ha 4.46 1.09 2.07 39.6 kg P/ha 3.83 1.04 2.03

F test a ** ns SEm ± 0.10 0.05 0.02 CV (%) 10.59 17.58 4.50 Interaction (main ns ns ns

**

× sub)

a ** = significant at 1% level, ns = not signifi- cant.

seedlings in two farmers’ fields in Guimba, Nueva Ecija, Philippines. We harvested 50 1-m 2 quadrats from areas in both fields where transplanted seedlings were contaminated with weed seedlings and 50 1-m 2 quadrats from areas where no weed seedlings had been transplanted.

In 1 field, yield from quadrats where an average of 29% of the hills were infested with Echinochloa glabrescens

was 372 g/m 2 ; in areas where no weed seedlings were transplanted, the yield was 476 g/m 2 . In the other field, yield from quadrats where an average 23% of the hills were infested with Echinochloa oryzoides was 434 g/ m 2 , 18% lower than the 530 g/ m 2 yield where no infestation was observed.

infested and weed-free hills were highly significant in both fields.

Differences in yield between the weed-

Rice grain yield (variety IR6) and fertilizer efficiency as affected by different N sources and their methods of placement. Islamabad, Pakistan, 1982.

Treatment a Grain yield b Fertilizer efficiency (t/ha) (kg yield/kg N used)

Control 3.2 f

46 kg N/ha as calcium ammonium 4.6 e in puddled soil (2/3 basal + 1/3 at PI) 46 kg N/ha as urea incorporated 5.0 d

nitrate incorporated in puddled soil (2/3 basal + 1/3 at PI) 46 kg N/ha as urea all incorporated in dry soil c

5.6 c

46 kg N/ha as USG deep placed, 4 DT 5.6 c 92 kg N/ha as urea incorporated in 5.6 c puddled soil (2/3 basal + 1/3 at PI) 92 kg N/ha as calcium ammonium 5.1 d nitrate applied in puddled soil (2/3 basal + 1/3 at PI) 92 kg N/ha as urea all incorporated in dry soil c 6.4 ab 92 kg N/ha as USG deep placed, 4 DT 6.6 a

SE 1.1

41.2

30.9

–

5 3.5

54.2 26.4

21.7

35.7 37.6 –

a PI = panicle initiation, DT = days after transplanting. b Means followed by the same letter are not significantly different at the 5% level of significance by DMRT. c The field was irrigated and planted after dry soil incorporation.

Weed seedlings transplanted with rice seedlings reduce grain yield Phosphorus application in acid-

sulfate soil A. N. Rao and K. Moody, IRRI

IRRN 12:3 (June 1987) 51

A phosphate slurry was prepared by mixing superphosphate with soil and water in the ratio 1:1.5:2.5. Seedlings were dipped in slurry for 12 h before transplanting. About two-thirds of the slurry was consumed in treatment; the leftover was uniformly applied to the relevant plots to maintain a P level 17.5 kg/ha.

In basal and split application, superphosphate was broadcast on the

of

soil surface. Missing hills were counted at panicle

initiation. Lodging was scored on a 1- 9 scale at maturity. The crop was harvested between 26 Oct and 8 Nov, depending on crop maturity in the different treatments.

52 IRRN 12:3 (June 1987)

We studied the effect of S source and fertilizer on yield, verified earlier finding on applying 100 kg N/ ha as urea with 1/2 t gypsum/ ha, examined the effect of adding gypsum with the common farmer practice of 17:17:17 mixture and DAP, and separated the effects of Ca and S.

A 1980-81 kharif field trial involved 14 treatments in a randomized block design with 3 replications. Plot size was

Effect of P application on agronomic characters, yield and yield components of lowland transplanted rice in acid-sulfate soils. Cuu Long Delta, Vietnam,

24 m 2 . Soil was sandy clay loam, pH

with 273 kg N/ha, 7.32 kg P/ha, 292 kg 7.6, low soluble salts, EC 0.4 mmho/cm,

1983 wet season.

Method of P application

Control Full as basal 1/2 basal + 1/2

at 15 DT 1/2 at 15 DT + 1/2

at 30 DT Full at 15 DT Seedling root dipped

in P slurry Full as basal

CD (0.05) CV (%)

Rate Seedling Plant Days to

(%) (cm) heading (kg P/ha) mortality ht 50%

0 39.6 95 107 17.5 1.7 120 96 17.5 1.8 120 97

17.5 16.7 105 103

17.5 11.1 109 102 17.5 3.1 115 100

26.2 1.2 125 96

Lodging Panicles/ Panicle Panicle Filled (1-9 scale) hill length wt grains/

(cm) (g) panicle

1 4.2 17.5 1.43 30.5 5 9.0 19.9 2.38 57.8 3 8.9 20.0 2.16 54.3

1 6.7 18.8 1.93 51.8

1 7.2 19.0 1.80 46.5 3 9.6 18.9 1.90 51.7

5 9.2 19.5 2.08 53.3 1.6 1.2 0.20 11.3

14.2 4.2 7.0 15.3

Unfilled 1000- Grain Response to grains grain yield P (kg grain/

(%) wt (g) (t/ha) kg P applied)

33.6 31.6 0.96 32.4 27.2 4.26 188.5 38.5 28.5 3.92 169.1

29.1 27.0 2.31 77.1

33.4 28.3 2.85 108.0 35.2 28.1 4.12 180.5

34.5 27.9 4.11 180.0 5.6 2.6 0.55

11.1 6.1 11.5

low pH at planting and acute P deficiency are the major problems on these soils.

wet season to evaluate the effect on stand establishment and yield of methods of applying P. Seven treatments were tested in a randomized block design with four replications. The soil was clayey with 0.232% total N, 0.027% total P, 0.52% SO 2 - 4 , 1.111 meq Al +3 /100 g soil, and pH 3.7 at transplanting.

old E425 seedlings spaced 20 × 15 cm.Al1 plots received 80 kg N/ha as urea (30 kg N/ha basal + 20 kg N/ ha 15 d after transplanting [DT] + 30 kg N/ ha at 40 DT) and 20.5 kg K/ha as muriate of potash. P was applied as superphosphate (9% P).

We conducted a field trial in the 1983

On 27 Jul 1983, we transplanted 38-d-

Basal application, irrespective of quantity applied, resulted in lower seedling mortality (see table). It also appears to have augmented root development, increasing nutrient absorption.

short, and erect leaves with dirty dark green color and stunted plants with limited tillers — were high in control. Basal P enhanced tiller production and plant height and hastened crop maturity. That crop lodged moderately because of increased height and heavier panicles, but lodging did not affect grain yield.

Symptoms of P deficiency — narrow,

Effect of sulfur source and fertilizer on rice yield

C. Paulraj and C.S. Balasundaram, Soil Science and Agricultural Chemistry Department, Tamil Nadu Agricultural University, Madurai, India

At 17.5 kg P/ha, basal P resulted in significantly higher grain yield than other P application methods except seedling root dipped in phosphate slurry and split-applied P (1 / 2 basal + 1 / 2 at 15 DT). Basal application increased the yield mainly through increased number of panicles (higher survival of seedlings and more effective tillers/ hill) and filled grains/ panicle. Higher 1 ,000-grain weight in the absence of P might be attributed to reduced competition among fewer spikelets in the panicle.

Basal application of 17.5 kg P/ha resulted in maximum P efficiency.

Grain and straw yields with different S fertili- zers. Madurai, India, 1980-81 kharif.

Treatment a Grain Straw (t/ha) (t/ha)

Control 4.0 5.9 U 100 kg N/ha + CaO 27 kg/ha 4.3 6.6

AS 100 kg/ha alone 5.1 7.3 U 100 kg N/ha + elemental S 5.2 9.9

U 100 kg N/ha + elemental S 4.8 9.4

U 100 kg N/ha + G 250 k/ha 5.4 10.9

(20 kg Ca/ha)

30 kg/ha

60 kg/ha

U 100 kg Nha + G 500 kg/ha 6.1 12.3 CaO 27 kg/ha alone 3.6 5.8

DAP 22 kg P/ha alone 4.0 6.9 TSP 22 kg P/ha alone 3.5 7.2 G 500 kg/ha alone 3.7 5.6 17:17:17 mixture 3.8 6.9 DAP + G 500 kg/ha 5.4 7.4 17:17:17 mixture + G 5.1 6.1

500 kg/ha CD 0.4 0.3

(20 kg Ca/ha)

a U = urea, AS = ammonium sulfate, DAP = di- ammonium phosphate, G = gypsum, TSP = triple superphosphate.

Rice-based fish and vegetable cropping system in coastal saline soils

C.R. Biswas, Central Soil Salinity Research Institute (CSSRI); G.N. Chattopadhyay and P.K. Chakraborty, Central Inland Fisheries Research Institute (CIFRI); A.K. Bandyopadhyay, CSSRI, Regional Research Station Canning, India 743329; and A. Ghosh, CIFRI, Barrackpore, India

In the coastal saline soils of the Sundarbans, rice is grown only during the monsoon season. No crop is grown during the winter and summer seasons because good quality irrigation water is lacking and soil salinity is high. Saline water is plentiful throughout the year.

K/ ha, and 18 kg S/ ha. elemental S, and calcium oxide were 17:17:17 mixture and DAP equaled urea Urea to 100 kg N/ha was added with applied basally. at 100 kg N/ha plus gypsum at 1/4

the 17:17:17 mixture and with DAP. Urea at 100 kg N/ha plus gypsum at t/ha. S enhanced yield more than Ca. Muriate of potash at 42 kg K/ha was 1/ 2 t/ha overwhelmingly increased yield Gypsum is an easily available and applied for all treatments. Gypsum, (see table). Gypsum at 1/ 2 t/ha with cheaper source of S than elemental S.

Efficiency of phosphorus form combined with organic manure in rice - rice cropping

V. Kr. K. Karuppiah and G.S. Thangamuthu, Agronomy Department, Tamil Nadu Agricultural University, Coimbatore, India

We compared direct and residual effects of phosphate rock and superphosphate on IR20 in 1982-83 kharif (wet season) and rabi (dry season). Treatments were imposed on the kharif crop, residual effects were studied on the rabi crop in a randomized block design replicated three times.

Both crops received 100 kg N and 42 kg K/ ha. Soil was clay loam, with 220 kg available N/ ha, 4.3 kg P/ ha, 271 kg available K/ ha, and pH 8.0. Organic manures were farmyard manure

Grain yield and return of phosphate and organic manure combinations. Coimbatore, control. India, 1982-83.

Grain yield

Treatment (t/ha) Return a / $ invested

Kharif Rabi

Farmyard manure 4.7 4.7 1.87

Farmyard manure 5.4 5.0 2.06

Farmyard manure 4.9 5.4 2.10

Compost alone 4.7 4.8 1.98 Compost + 5.6 4.6 2.03

Compost +rock 5.2 5.0 2.12

Greenleaf manure 5.9 4.8 1.93

Green leaf + 5.9 4.9 2.09

Green leaf + 5.0 5.3 2.03

alone

+ superphosphate

+ rock phosphate

superphosphate

phosphate

alone

superphosphate

(FYM) — 0.05% N, 0.11% P, 0.42% K; composted water hyacinth — 1.5% N, 0.34% P, 1.25% K; and leucaena green leaf manure — 3.0% N, 1.7% P, 2.08% K.

rock phosphate improved when they were combined with organic manures (see table). Superphosphate applied with organic manure had highest direct effect. Superphosphate with leucaena green leaf

The efficiency of superphosphate and

manure was best. Rock phosphate efficiency improved with composted water hyacinth.

Residual effects of all organic manures and P were equal. Rock phosphate with organic manure was better in obtaining high grain yield. FYM was the best in improving rock phosphate efficiency. Composted water hyacinth with rock phosphate gave the highest net return.

Effect of Azospirillum on ASD16 rice

D. Alice and M. Subramanian, Rice Research Station, Ambasamudram 627401, India

We evaluated the effect of Azospirillum on grain yield of ASD16 (110 d duration) Jun-Oct 1986. Five N levels (0, 25, 50,75, and 100 kg/ha) and 4

Azospirillum treatments (control, seed treatment, seedling dip, and field application) were examined in a split- plot design with 3 replications. Available NPK was 298-75-164 kg/ha.

Yield differences due to Azospirillum treatment as well as the interaction between Azospirillum and N levels were not significant. All four N treatments were significantly superior to the

Rice-Based Cropping Systems

Yield and income with different rice - fish - vegetable cropping systems in Barrackpore, India, 1982-85.

Cropping Yield Gross Net

pattern (t/ha) ($/ha) ($/ha) return

Rice 3.4 398.00 150.00 Rice + 3.4 855.30 395.30

freshwater fish 0.5 Rice - 3.4 1297.60 624.60

brackish water 0.5 rock phosphate fish

Superphosphate 5.4 4.9 2.10 alone + freshwater fish 0.5

Rock phosphate 4.4 4.9 1.90 - brackish water 0.5 alone fish

Contro1 (no Organic 4.0 4.0 1.54 manure) + freshwater fish 0.5

-brackish water 0.5 fish

+ vegetables 10.7

Rice 3.4 1754.90 869.90

3.4 2594.30 1294.30

CD (0.05) 0.1 0.5

a Av of 2 seasons.

IRRN 12:3 (June 1987) 53

Rice

return

We conducted inter-institute collaborative trials for 4 yr to expand land use through rice - fish culture followed by brackish water fish culture with vegetable cultivation on the bunds. (The vegetable crop was grown only in 1985.)

Freshwater fish (carp and

Transplanted aman - potato - maize cropping pattern in Bangladesh

N. A. Khondaker and M. M. Ullah, Regional Agricultural Research Station, P. O. Hathazari, Chittagong, Bangladesh

We studied a transplanted aman rice - potato - maize cropping pattern for 2 yr in farmers’ fields at 3 sites in Chittagong District and compared it with farmers’ cropping patterns. The cropping pattern was replicated on five farms in partially irrigated uplands.

In the improved cropping pattern, maize variety Sadaf was introduced as an alternate crop to broadcast local aus variety Chinnal, potato variety Cardinal as an alternate to the farmers’ local variety, and transplanted aman variety BRII to Pajam. The fields were fertilized with 80-60-40 kg NPK/ha for

Announcements

Two IRRI scientists awarded Japan‘s top science prize

Sharing the 1987 Japan Prize are Dr. Henry M. Beachell, former IRRI plant breeder, and Dr. Gurdev S. Khush, currently head of IRRI's Plant Breeding Department. The Prize — patterned “in the tradition of the Nobel Prize” — is Japan’s most prestigious.

The award was given 14 Apr in Tokyo in the presence of Japan’s Crown Prince Akihito and Crown Princess Michiko, Prime Minister Yasuhiro Nakasone, and foreign dignitaries. On 15 Apr, Emperor Hirohito received the rice scientists at the Imperial Palace.

Beachell, who joined IRRI in 1963,

54 IRRN 12:3 (June 1987)

Macrobranchium rosenbergil ) with rice during the monsoon season approximately doubled returns (see table). Brackish water fish ( P. monodon and L. parasia ) during the fallow period increased gross income four times. Rice and freshwater fish during the monsoon and brackish water fish during the

fallow increased returns five times. Vegetable crops along the field borders with rice and freshwater fish followed by brackish water fish increased income eight times.

It was possible to get 2 fish crops, 1 rice crop, and 1 vegetable crop in 1 yr from 1 field by judicious land use.

Yield a of transplanted aman - potato - maize cropping pattern at 3 sites in Bangladesh, 1983-85.

Crop Yield (t/ha) Material cost Net return

Patiya Satkania Fatikchari Mean CV (%) ($/ha) ($/ha)

Farmers’ pattern Transplanted aman 2.4 2.4 2.5 2.4 1.6 89 258 Potato 8.2 7.7 5.5 7.1 16.2 219 323 Broadcast aus 2.0 1.9 2.0 2.0 1.1 42 209

Transplanted aman 4.0 4.0 4.1 4.0 1.7 102 429 Potato 21.6 25.4 21.6 24.9 10.0 491 1126 Maize 4.6 4.4 4.2 4.4 3.8 117 588

a 2-yr av.

Improved pattern

transplanted aman, 120-100-100 kg potato, and 30 kg/ ha for maize. All NPK/ha for potato, and 100-60-40 kg crops in all locations received normal NPK/ha for maize. Spacing was 25 × cultural treatments. 15 cm for transplanted aman, 60 × 30 Average yields for 2 yr are presented cm for potato, and 75 × 25 cm for in the table. Net return for the improved maize. Seeding rate was 80 kg/ha for pattern was 171% of the farmers’ transplanted aman, 1,500 kg/ ha for cropping pattern.

was honored for his work on IR8, the With good management, IR8 yielded first semidwarf rice variety to be widely 4 or 5 t/ha on irrigated farms; grown in the tropics. Khush, who joined traditional varieties yielded 1 or 2 t. The IRRI in 1967, led the effort that increased farm productivity that developed IR36, which became the most followed in the wake of IR8 gave rise to widely grown variety — of any crop — the term “Green Revolution.” the world has ever known. By 1983, IR36 was developed under Khush’s IR36 was planted on 11 million ha in leadership from crosses involving 13 Asia, Africa, and Latin America. parents from 6 countries. It was

selection of IR8, which IRRI released in IRRI and in national agricultural late 1966 from a cross of a dwarf rice programs throughout Asia. IR36 was from China with a vigorous Indonesian first named as a farm variety in 1976 in variety. IR8 had short, stiff straws that the Philippines, then released by enabled it to yield heavily without falling national agencies across Asia, Africa, over. Its insensitivity to daylength meant and Latin America. that farmers could grow it around the The popularity of IR36 was due world. largely to its genetic resistance to a

Beachell played a key role in the evaluated cooperatively by scientists at

dozen insects and diseases, which decreased farmers' dependence on pesticides. IR36 also has resistance to environmental stresses such as drought and N-deficient soils.

IR36 matures in about 105 d in contrast to 130 d for IR8 and 150-170 d for traditional varieties. Its slender grains are generally considered superior to those of most earlier semidwarfs. IR36 has been especially popular in the Philippines, Vietnam, Indonesia, India, Malaysia, Kampuchea, Laos, Bangladesh, and Sri Lanka.

IRGC user guidelines

The International Rice Germplasm Center (IRGC) has more than 80,000 rice accessions and responds to requests for seed samples from rice breeders all over the world. To facilitate IRGC services so that you receive the seeds you want in the shortest time possible, these guidelines have been established:

• The IRRI accession numbers in our seed list indicate different origins/ seed sources/ecostrains/morphologic variants/polymorphic populations. Use the IRRI Acc. No. whenever you can. Retain our seed list for future reference.

• The amount of seed provided is limited to 10-20 g for each rice variety or breeding line and 10-50 seeds for a population of wild species.

• For larger quantities of IR varieties and promising lines, please write the IRRI Plant Breeding Department or the International Rice Testing Program.

• If IRGC seed stocks are depleted, the term "insufficient seed" in our reply indicates that shipment will be sent after a successful seed rejuvenation.

• If requested far enough in advance, IRGC may make a special seed increase of a few accessions, if the need is warranted and our time and space permit.

• Please spell the variety names

Beachell, born in Nebraska, USA, in 1906, was a rice breeder with the U.S. Department of Agriculture at Beaumont, Texas, for 30 yr before he joined IRRI. From 1972 to 1982, he worked with an IRRI project at the Central Research Institute for Food Crops in Indonesia. He is now a plant breeder with Farm of Texas Co., Alvin, Texas.

Khush was born in 1935 in Punjab, India. He was a geneticist at the University of California, Davis, before joining IRRI.

carefully because a misspelled name may not be readily located. It would be helpful to indicate the desired traits so that additional materials may be sent.

• If you specify your needs, IRGC can ask the IRRI Statistics Department to provide the biotic, edaphic, and ecological stress characteristics of the accessions you receive, using available morphoagronomic and other evaluation data files. A computer printout will accompany our covering letter.

• If you wish genetic testers for one of the major diseases or insects, please indicate that you need purified seed stock. The original population is likely to be heterogeneous. Most IRGC accessions do not qualify as purelines, particularly those of varieties collected from farmers' fields. We do judicial purification, but not to an extent that would change the genetic composition of the original population.

• Wild rices are generally heterogeneous populations or hybrid swarms. They require special care. Guidelines on growing the wild rices will accompany our letter with your shipment.

• If you wish to retest an accession you received earlier, be sure to use the IRRI ACC. No. in our seed list. For some cultivars, we hold several accessions under the same variety name.

• Please acknowledge receipt of IRGC seeds so that we may know that the

Beachell and Khush are the first agricultural scientists to receive the Japan Prize. The Science and Technology Foundation of Japan initiated the Prize in 1985 to recognize persons who have "served the cause of peace and prosperity for mankind through original and outstanding achievements in science and technology."

The 1987 awardees were chosen from 510 top names in science nominated by fellow scientists from around the world.

shipment has reached you.

• We follow the plant quarantine regulations of the importing country. If necessary, the seeds will first be sent to the quarantine station of your country. If your country has special restrictions, please supply the information or send us the official seed import permit.

• If you do not hear from us more than 6 wk after writing, send another letter. However, you should allow for the time needed for letters to reach us, or for our reply to reach you: 2 wk within Asia, 2 wk from North America or Europe, 3 wk from South America, and 4 wk from Africa - one way.

• Rice breeders/researchers do not automatically deposit their promising or published materials in IRGC. If you have recent information about such materials, please supply the published paper reference so that we can request seeds from the original source.

• We welcome queries, suggestions, and comments on IRGC service. If you are in Los Baños, you can seek assistance from Mrs. Ched Parker or any IRGC staff member in obtaining the information you need. Or please write us and be specific about the information you need.

Individuals, organizations, and media are invited to quote or reprint articles or excerpts from articles in the IRRN.

IRRN 12:3 (June 1987) 55