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PROGRAM 2

SUSTAINABLE PRODUCTION SYSTEMS

Program Leader: Prof Graeme Batten Charles Sturt University Wagga Wagga

Rice CRC Program 2 addresses strategic issues relating to the long-term sustainability of rice production. The objective is to develop a comprehensive understanding of the mechanisms operating in the soil, plant and biological environment that could be manipulated to achieve sustainable high grain yield with high quality, while minimising the impact of intensive rice production on the environment. Significant reductions in water requirements per tonne of rice are sought through improved tolerance to cold, better recovery of applied fertilisers and reductions in chemical usage. During the sixth year of this Program, 19 projects were in progress. Activities included collecting soils, analysing soils by chemical and physical techniques, growing and collecting rice plants to study reactions to cold, studying the influence of genotypes and nutrient supply on yield and grain quality, and seeking non-chemical crop protection. Scientists in Program 2 continue to develop valuable linkages with staff and students in many Rice CRC projects, with RIRDC projects, and with scientists at other Australian and international research centres. Specific goals are:- * an improved understanding of the changes in soils used to grow rice to achieve higher

yields per unit of water and fertiliser input; * an enhanced understanding of the ability of the rice plant to respond to changes in its

environment, specifically rice which can withstand minimum temperatures 4ºC lower than current varieties at the reproductive stage;

* the development of reliable rapid tests for nitrogen, nutrients and salinity in rice soils; * the evaluation of germplasm which will enhance the quality of rice produced in the

Australian environment; * development of a field technique to grow grains with predetermined mineral or quality

traits; and * decreased dependence on agricultural chemicals for weed and insect control and to

maintain comparative freedom from major pests and diseases.

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Increasing the nutritional value of rice grain (Graeme Batten and Tina Dunn) About one third of the world’s population suffers from health problems due to mineral deficiencies in their diet, in particular iron. Rice CRC Sub-Program 2.3, led by Prof. Graeme Batten, has been investigating the possibility of manipulating the iron and zinc concentration in rice grain. Prof Batten and Masters student, Mr Rob Duncan, reported that iron and zinc applied to rice plants in the early grain filling stage increased iron and zinc in the grain. To confirm these findings Dr Lindsay Campbell, with Prof Batten and Mrs Tina Dunn, set up a series of experiments at Yanco Agricultural Institute. Three different iron solutions and two different zinc solutions were applied to trial plots jus t after anthesis. At maturity total dry matter, yield and percent grain sterility were all measured and samples taken to determine iron and zinc concentrations in the grain. These experiments have shown very promising results. The three iron applications increased iron concentrations in the harvested grain. Both zinc applications raised zinc concentrations in the grain with no apparent loss in yield. It was found however, that if the grain was milled to produce white rice, the foliar applications made no difference to the resulting mineral concentration in the grain. This work fits with important studies generated from the International Rice Research Institute, Philippines and the USDA-ARS at Cornell University. They are attempting to improve human nutrition by producing cultivars with the ability to accumulate high iron content.

2.1 Managing soil chemical, physical and biological properties to achieve yield and environmental quality

Sub-Program Leader: Assoc Prof Scott Black/Prof Graeme Batten Charles Sturt University Wagga Wagga

The state of the soil resource and our ability to manage it are pivotal to rice production. Nitrogen is the key nutrient in rice production so techniques are required to estimate the pre-sowing fertiliser input needed to ensure optimum yields and grain quality. In this Sub-Program the significance of long-term fertility trends and variability within and between crops is being studied using a combination of traditional chemical and airborne sensing techniques. These data will provide a base to define potential limits to future production.

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A strategic soil nitrogen test for flooded rice (2101)

Project Leader: Assoc Prof Scott Black/Dr Craig Russell Charles Sturt University Wagga Wagga

Objective To develop a commercial test to predict soil nitrogen supply to rice.

Progress Applying N fertiliser before flooding gives a greater rice yield response than topdressing, but there is no method for rice growers to decide on the optimum rate of pre-flood N. The first step in developing a soil N test was to evaluate calibrations of soil near infrared (NIR) spectra with N mineralisation and growth of rice crops. The calibrations were developed using 10 cm deep soil samples collected from 130 experiments conducted on rice farms from 1998 to 2001. The relationship between NIR and crop growth is not close enough for a reliable soil test, but the relationship between NIR and mineralisation is sufficiently precise to indicate soil-N status (standard error = 27 ppm NH4

+-N in a data range of 25-225 ppm). Having estimated mineralisation, it is still necessary to predict crop growth. From the same set of experimental data, crop growth is estimated from soil mineralisation with a standard error of 3.3 t/ha in a data range from 12 to 25 t/ha). The combination of the NIR test and prediction of crop growth is capable of distinguishing 4.1 classes of soil-N status. Evaluated in the same way, the commercial N test of rice plants at panicle initiation can distinguish 5.6 classes of crop-N status. The reason for the low precision of the soil test appears to be that rice roots explore different amounts of topsoil, depending on cut and fill status, while soil samples are taken to a constant depth. The consequence of a large standard error for the soil test is that there is a risk of over-fertilisation, leading to lodging and cold damage. While there is some scope for reducing the standard error, the soil test is unlikely to be suitable for predicting optimum pre-flood N applications for whole fields. There may be scope for using a soil-N test for variable management of pre-flood N fertiliser and measuring N with other soil properties using NIR.

Application of spatial data analysis (2102)

Project Leader: Dr John Louis/Ms Sarah Spackman Charles Sturt University Wagga Wagga

Objective To utilise remote sensing to quantify within field rice biomass variability and to incorporate this spatial biomass variability into maNage Rice™ to predict yield response to N application at panicle initiation.

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Progress The research into combining airborne multispectral imagery with the “maNage Rice” decision support system has been completed. The writing of the dissertation has yet to be finalised, however all results and analysis are completed. Zonal management of fields using maNage Rice estimates has proved to be theoretically economical and has the potential to provide useful within-field N management information leading to increased grain yield. The errors in predicting yield using MaNage Rice in the fields investigated were found to be statistically significant, with a systematic offset/bias of 1 t/ha. The residual mean squared (rMS) errors using ground measured dry weight input into the model were around 2.5 t/ha, whilst remotely sensed estimates of dry weight used as input into the model produced rMS errors of around 3.5 t/ha. The remote sensed estimates of dry weight used in this study were obtained from the CSU Multispectral Airborne Video System (MAVS). This system is no longer in operational use. Dry weight calibration coefficients obtained with the newer Multispectral Airborne Digital Imaging System (MADIS) may vary slightly, however these instrument-related calibration differences would be minor compared to those associated with natural variations between fields and phenological stages.

Outcomes * Remote sensing can quantify within-field variability. * The maNage N rice model has a significant bias. * Zonal application of N within fields is theoretically economic.

Impact of the Australian rice farming systems on the soil sustainability (2103)

Project Leader: Dr Harnam Gill NSW Agriculture Yanco

Objectives This project aims to:- * evaluate the long-term impact of the common rice farming systems on the changes in

important properties of the prevalent soils; and * establish sites typical of the Australian rice farming systems for future monitoring and

quantitative assessment of changes in the soil properties pertinent to sustainable rice productivity.

Progress Analysis and verification of accuracy and precision of analytical results of 652 soil samples collected from 326 sites in 1998/1999 and 1999/2000 were completed. Analytical parameters

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include total soil C, N, and S (by LECO), pH in water and 0.01 M CaCl2, EC, total P, available P (Olsen-, Colewell-, and Bray(1)-extractable), exchangeable cations (Al+++, Ca++, Mg++, K+, and Na+), DTPA-extractable Fe, Mn, Zn and Cu, and total nutrient metals (Ca, Mg, Na, K, Fe, Mn, Zn, Cu, P, S). Samples were taken from CIA (53), MIA Leeton (99), MIA Griffith (66), 41 EMV, 16 WMV rice paddocks and fence lines. In addition, 25 plots of a long term trial at NSW Agriculture’s Deniliquin site were sampled in both the years. Each site, either a rice paddock or the cut and fill areas within a paddock, was sampled separately to collect a surface (0-10 cm) and a sub-surface (10-30 cm) sample. Each sample is a composite of 20 samples drawn from as many locations within a rice paddock or cut and fills areas. All the sampling locations within each site were recorded using appropriate GPS equipment. All the soil samples after their collections were air-dried (40 °C) before grinding to pass through a 2 mm sieve. After a thorough mixing, approx. 1 kg soil of was stored in high-density polyethylene bottles creating a library of the soil samples for future use. A sub-sample of each soil was further ground to pass through a 250 µm sieve for analytical parameters (exchangeable cations, LECO, ICP testing of total nutrient metals). Some of the analytical results on the soil samples analysed for this project are presented below regardless of the variation due to different soils, cropping systems, cut and fill areas etc. * Total Soil Carbon Total soil carbon data (Figure 8) show significant variation among the sampled rice paddocks regardless of soil types, farming system, cut and/or fill areas, and the recent paddock history. Total C content of the surface (0-10 cm) layer is significantly more than the sub-soil (10-30 cm). Variation in surface soil ranged from 1.0% to 3.0% in most rice paddocks whereas its amount in the sub-soil was between 0.6% and 1.4%. The three-fold variation in the total soil C in surface soils is a promising indicator of variation in organic matter content and the storehouse of N, P, S and some micronutrients. This means significant variation in the impact of soils on the availability and N supplying capacity of soil or native N. In addition, soil availability of P, S, Zn, and Cu is also expected to be affected differently. Paddocks where rice is essentially grown in rotation with pastures showed on an average total soil C of about 2% whereas paddocks that grow rice in rotation with winter cereals had significantly lower total soil C. Among the various rice districts, CIA paddocks were comparatively lower in the organic matter content of the surface layer. These results suggest that research needs to be done aimed at improving our understanding of the role of organic matter in the regulation and control of nutrient supplying capacity of soils with different properties. * Soil reaction Results on soil reaction (Figure 9) as measured by pH of soil in 0.01 M CaCl2 (1:5 soil-solution ratio, w/w) show that surface soil of most rice paddocks tested between 5 and 7, whereas sub-soil indicated a pH variation between 6.0 and 8.5. Some of the surface soil paddocks had pH less than 5.0. Acidity of surface layer can significantly affect nutrient supplying capacity of rice paddocks when upland crops are grown in rotation with rice. However, flooding in rice alleviates soil acidity through reduction of the soil. Pasture-based rice paddocks had relatively lower soil pH than the ones where winter cereals are grown in rotation with rice. Soil pH did not show a relationship with intensity of rice crops grown on a paddock in the past. Other salient findings were :- * red brown earth paddocks are relatively more acidic than others;

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* dedicated pasture paddocks have low pH but higher total soil carbon than paddocks where rice is rotated with cereal crops such as wheat, barley, and oats;

* soil fertility in general and the soil organic matter in particular is decreasing gradually with increased cropping in rice paddocks; and

* soil salinity and sodicity do not appear to be a major problem in the root zone of the rice crop.

* Future work Analysis and processing of data on analytical parameters is in progress for final submission of the final report as well as the publication of research and technical findings.

Figure 8. Variation in total soil carbon of the surface and sub-surface soil in the selected sites.

Figure 9. Variation in the pH1:5 in 0.01 M CaCl2 of surface and sub-surface soil in the selected sites.

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2.2 Crop management in relation to environmental change

Sub-Program Leader: Mr Rob Williams/Dr Ranjith Subasinghe NSW Agriculture Yanco

Temperature at the reproductive stage is the most important contributor to the yearly variation in grain yield, with cool night temperatures prior to flowering drastically reducing yields. The average commercial rice yield in 1996, for example, was only 6.5 t/ha, compared with the record 10.3 t/ha in 2003. Some crops in 1996 yielded less than 1 t/ha – a devastating result for those growers. Irrigation water is used to protect rice from cold. During the sensitive reproductive developmental phase, rice growers are advised to increase the depth of water in the crop to at least 20 cm. The aim is to maintain the temperature of the developing panicle above 18°C. Cold at the reproductive stage particularly affects pollen development. The most sensitive stage is understood to be the early microspore stage, just following pollen mother cell meiosis when single pollen grains are just beginning to fill with starch. Rice CRC projects in this Sub-Program are particularly aimed at understanding the response of rice to cold at the reproductive stage so that yield stability from year to year can be achieved.

Cold physiology at the plant level (2201)

Project Leader: Dr Laurie Lewin/Mr Tim Farrell NSW Agriculture Yanco

Objectives The aim of the project is to develop a screening technique at flowering to identify low temperature tolerant rice varieties in the glasshouse and field environments.

Progress * Cool water testing A trial similar to the previous trials during the last two seasons was again conducted using the cool water system. The capacity of the system was increased with the installation of three large circular tubs (6.84 m2). Each tub represented a replicate. 200 varieties/lines from diverse origins were screened using the cool water system. They were exposed to a constant water temperature of 19°C from panicle initiation (PI) until head emergence. Baijiemang (China), Slavyahez (Russia), Jemchjniy (Russia), Lijiangheigu (China) and Pavlovsky (Russia) were the best performed varieties, exhibiting less than 40% sterility under cold water conditions. However, there was an excessive amount of cold damage, with 136 of the 200 varieties tested having greater than 90% sterility. The water

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depth (42 cm) to which plants were exposed was a contributing factor for the high sterility compared to previous investigations. Despite this, the susceptibility of Doongara (Australia) and Sasanishiki (Japan) to cool temperatures was again confirmed (95% sterility). The fluctuation of seasonal temperatures (both day and night) does not appear to have an effect on the temperature of the water in the system. There was minimal difference between the mean maximum (19.2°C) and the mean minimum (18.8°C) water temperature recorded. Therefore, a stable temperature is maintained in the system and contributes to the success of cool water screening.

The cold water screening system for the 2002/2003 season.

* Field trials A replicated field trial was established in the 2002/2003 season and included 50 varieties from diverse origins with differing levels of cold tolerance. Four sowing times ranging from October 8 to December 17 were used, with each sowing time replicated twice. A shallow water depth (10 cm) was maintained and a nitrogen rate of 200 kgNha-1 was applied at the three to four leaf stage, to maximise the chances of cold damage. Preliminary sterility data indicates that there was very little cold damage during the season. Phenology data for all varieties in all bays was recorded and samples were collected for key measurements (pollen number and anther length and width) at flowering. Analysis of the data is in progress and varietal response to Australian conditions will be determined. • Future work The focus for the 2003/2004 season will be the screening of several varieties from diverse origins for cold tolerance using the cold water facilities. Due to excessive amounts of cold damage last season, the plants will be exposed to a water depth of 30 cm compared to 42 cm in 2003. Critical flowering characteristics (pollen number, anther length and width, and stigma size) will be measured in both control and treatments. Field trials will not be conducted during the coming season because they are less effective in imposing cold conditions during the critical young microspore stage.

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Effect of nitrogen and low temperature on reproductive development (2205)

Project Leader: Prof Shu Fukai University of Queensland St Lucia

Mr Thusitha Gunawardena has completed his studentship and has been awarded a PhD in Crop Physiology/Agronomy. A synopsis of his thesis titled “Spikelet sterility in rice (Oryza Sativa L.) induced by low temperature and nitrogen” is provided. Low temperatures impose restrictions on rice (Oryza sativa L.) production at high latitudes. This study is concerned with low temperature damage which can arise mid-season during the panicle development phase. Low temperature damage at this phase is exacerbated by high application rates of nitrogen (N) fertilizer. The objectives of this study were: (1) to investigate the mechanisms of spikelet sterility caused by low temperature during reproductive development under different N conditions; and (2) to determine whether low temperature experienced by the root, panicle or foliage is responsible for increased spikelet sterility. The problem was investigated under field and temperature-controlled glasshouse conditions. Four seasons of field experiments were conducted at Yanco Agricultural Institute (YAI) (34°37’S, 146°25’E; alt. 140 m), in a temperate rice-growing region in southern NSW. Treatments in the field and glasshouse experiments included N rates from zero to very high (ie, 300 kg N ha-1) to achieve variation in N status of the crop. To increase the chance of low temperature occurring during panicle development, plants were sown 2 - 3 times in each field experiment. In the glasshouse experiments, 12 h periods of low (18/13°C) and high (28/23°C) day/night temperature were imposed over periods of 5 - 7 days during panicle development. In the glasshouse experiments, water depth and water and air temperatures were changed independently to investigate the effects of low temperature in the root, panicle and foliage on spikelet sterility. In all field and glasshouse experiments, the number of engorged pollen grains per anther, spikelet sterility and grain yield were measured. In the field, low minimum air temperature during microspore development (ie, 18 - 11 days before flowering) and at around flowering increased spikelet sterility. Minimum temperature below 20°C increased spikelet sterility; each 1°C decrease during microspore development and flowering increased sterility by 1.4 and 0.9%, respectively. Therefore, the microspore development period appeared to be more sensitive to low temperature than was the flowering period. Also in the field, an average minimum air temperature of 13.8°C during microspore development in shallow-watered (8 cm) fields resulted in 25% spikelet sterility. In the glasshouse experiments, an average minimum temperature of 13°C during microspore development caused 51% spikelet sterility. The study of past temperature records at YAI has shown that, in 14% of the years, rice would be exposed to an average minimum temperature of < 13°C for 10 days during microspore development which occurs in late January. This would be expected even when the crop is sown early in the season (ie, early October). An increased number of engorged pollen grains per anther at heading resulted in more pollen grains being intercepted by the stigma at flowering. Consequently there was an increased number of germinated pollen grains on the stigma. Low temperature (18/13°C) imposed on the whole plant for 5 - 7 days during microspore development severely decreased the production of engorged pollen grains. This resulted in increased spikelet sterility.

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While engorgement efficiency (the percentage of pollen grains that were engorged) was determined by both root and panicle temperature, the germination efficiency (the percentage of germinated pollen grains relative to the number of engorged pollen grains intercepted by the stigma) was determined only by root temperature. The interception efficiency (ie, percentage of engorged pollen grains intercepted by the stigma), however, was not affected by either root or panicle temperature. Spikelet sterility can be expressed as a function of the number of total pollen grains per spikelet and the efficiencies with which these pollen grains become engorged, are intercepted by the stigma, germinate and are involved in fertilisation. Of these, engorgement efficiency was the dominant component, explaining the largest variation in spikelet sterility. Deep water (20 cm) in the field often protects the young panicle from being exposed to low air temperature. This practice, however, promoted culm elongation leading to the exposure of parts of the panicle with a consequent increase in sterility. Overcoming this effect requires increased water depth to achieve complete submersion of panicles. In glasshouse experiments, the detrimental effect of low air temperature was overcome by submerging panicles completely in water at 22°C even though the foliage was at low temperature. Low temperature damage resulted from exposure of the panicle, but low temperature in the root system also contributed to the damage. Low panicle and root temperatures appeared to have additive effects on spikelet sterility, but exposure of foliage to low temperature had no effect. Application of N exacerbated low temperature damage. In the absence of applied N, an average minimum temperature of 14°C over 7 days during microspore development across all experiments resulted in 21% spikelet sterility. This was increased to 42% where = 150 kg N ha-1 had been applied at the pre-flood (PF) stage. A decrease of 1°C average minimum temperature below 20°C during microspore development increased sterility by 3.2% and 1.3% with and without N applied at PF, respectively. The application of N decreased the number of engorged pollen grains per anther due, in part, to increased spikelet density. There was a significant combined effect of spikelet density and minimum temperature during microspore development on the number of engorged pollen grains per anther, resulting in variation in spikelet sterility. The application of N also increased panicle height mainly because of increased culm length. Hence, panicles were only partially submerged during microspore development. This appeared to be a further reason for the susceptibility of rice to low temperature when high rates of N are applied. This study demonstrated the usefulness of increased number of total pollen grains per spikelet to overcome the adverse effects of low temperature during microspore development, resulting in decreased engorgement efficiency. The mechanism involved at tissue or cell level in reducing the number of engorged pollen grains per anther when high rates of N are applied, however, remains unknown. Therefore evaluation of both quantitative and qualitative aspects of engorged pollen as affected by environmental variables is required further.

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Screening reproductive-stage cold tolerance for the NSW Rice Improvement Program (2206)

Project Leader: Dr Russell Reinke NSW Agriculture Yanco

Objectives * To establish a repeatable and reliable screening method of early generation rice

populations for reproductive-stage cold tolerance by determining the effects of temperature control of the glasshouse, temperature distribution within the glasshouse and duration of exposure to low temperature.

* To determine the heritability of reproductive-stage cold tolerance between the fourth and

fifth generations. A measure of the heritability and the nature of genetic variation for cold tolerance in early generations in the NSW Agriculture rice improvement program will facilitate rapid development of cold tolerant varieties.

Progress In autumn 2002 four experiments were conducted. Three experiments were designed to identify spatial temperature variability, firstly within the two rooms which comprise the glasshouse facility and secondly within the growth tubs which contain the rice plants. The fourth experiment aimed to identify the effect of duration of exposure to low night temperatures. Head selections were made from F3 populations with at least one identified cold tolerant parent. In spring 2002/autumn 2003, a further five experiments were conducted. Three of the experiments were repeated from autumn 2002 and had low levels of sterility. Other experiments screened advanced lines from the breeding program and F4 populations for cold tolerance. Head selections were again made from another suite of F3 populations with at least one identified cold tolerant parent.

Outcomes In autumn 2002 spatial variability was identified within the growth tubs. However, all experiments resulted in low levels of sterility in treated plants when compared to the control which was not indicative of the temperature regime. These experiments were harvested in spring 2002/autumn 2003.

Project success Identification of spatial effects on floret sterility within the growth tubs has significantly influenced the design of subsequent experiments.

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2.3 Mineral nutrition and grain quality

Sub-Program Leader: Prof Graeme Batten Charles Sturt University Wagga Wagga

Rice yield, grain quality and human nutrition are all influenced by the minerals available to roots and taken up by the plant. There are indications from intensive rice farms in the Murrumbidgee Irrigation Area (MIA) that mineral deficiencies may be impacting on some quality attributes. A better understanding of factors which influence the uptake and translocation of nutrients within the rice plant, especially to the grain, will place the industry in a better position to sustain rice yield potential and compete for markets which use grain quality and nutrition standards. The projects in this Sub-Program examine genotype, environment and management options that impact on production and quality. The staff is comprised of three scientists, two technical officers, one postgraduate student and one honours student.

Mineral nutrition (2301)

Project Leader: Prof Graeme Batten Charles Sturt University Wagga Wagga

PhD student, Rob Duncan, ceased work on this project some time ago to take up a position in a private company. Mr Duncan has recently forwarded a report on this project to the CRC and a summary is provided for information, particularly as it is relevant to current work outlined in Project 2302. * Detached panicles in solution culture to manipulate grain iron and zinc

concentration. Studying the effect of changes in the supply of a particular nutrient on the development of cereal grains is complicated by the inability to control the supply and composition of both organic and inorganic nutrients from other parts of the plant. Solution culture of detached panicles during grain development enables the supply of nutrients to developing grains to be controlled to a greater extent than is possible using whole plants. The purpose of this experiment was to determine whether or not it is possible to manipulate the concentration and contents of Fe and Zn in the developing rice grain by manipulating the supply of these nut rients in solution culture media, whilst keeping the supply of all other nutrients constant. Six rice cultivars (Illabong, Kyeema, Langi, Namaga and Opus, as well as a fragrant long-grain cultivar, A301, from the USA) were sown into a replicated field trial at Yanco Agricultural Institute. Panicles were tagged at anthesis and detached eight days later.

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Panicles of each cultivar were also tagged at anthesis and harvested in the field at physiological maturity. Detached panicles were cultured in solution media containing either a basal concentration of Fe and Zn (0.040 mM and 0.036 mM respectively), or a solution containing a five-fold increase in the basal concentration of Fe and Zn. Brown rice Fe concentrations of all cultivars were greater in detached panicles cultured in the high Fe/Zn media compared with those cultured in control media. Brown rice Fe concentration of field-grown plants tended to be higher compared with detached panicles cultured in the control media. Supplying a high concentration of Zn in the culture media failed to increase either brown rice Zn concentration or content compared with the control media (P > 0.05). Uptake of Zn by field-grown plants was invariably greater than for detached panicles in either culture media. Grain dry weights were higher in the plants which matured in the field.

Rice mineral requirements (2302)

Project Leader: Prof Graeme Batten Charles Sturt University Wagga Wagga

Objectives The World Health Organisation has identified widespread deficiencies of iron and zinc in humans. In Project 2301 genotype variation in Fe and Zn are being studied. The aim of this project is to determine the extent to which Fe and Zn can be increased through foliar applications of these elements.

Progress Field experiments have been conducted by Mrs Tina Dunn at Yanco over three seasons. Plots of the cultivars Namaga and Langi were established. At flowering three iron sprays and two zinc sprays were applied as foliar applications.

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Iron and zinc experiment at Yanco 12/11/02

An aerial NDVI image of Yanco rice area 31/12/02

Tina Dunn applying iron and zinc foliar sprays to plots using a hand boom

Increases in Fe in grain from the iron foliar sprays were recorded but as the Fe concentration in the grain increased, grain yield, brown grain dry weight and total dry matter all decreased. The zinc foliar sprays increased the zinc concentration and content compared to the control plots, all other data have shown no differences. Additional experiments are examining the impact of time of foliar applications on yield and grain Fe and Zn concentrations.

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Zn and Fe treatment results across varieties

Control Fe Librel FellS04 Ferriplex Supa Zn ZnS04 Lsd

(P< 0.05) % sterility 17.0 25.5 20.4 33.1 18.4 20.0 4.56 Fe(mg/kg) 13.2 18.3 15.8 20.3 14.2 12.9 3.65 Fe(ug/grain) 0.257 0.332 0.310 0.360 0.277 0.251 0.067 Grain yield (t/ha) 11.44 9.71 11.13 8.79 11.62 11.64 0.70 Zn(mg/kg) 19.7 20.8 19.2 22.7 26.0 25.3 2.64 Zn(ug/grain) 0.384 0.373 0.375 0.405 0.508 0.491 0.051 brown grain dry wt. (mg/grain) 19.57 18.17 19.59 18.01 19.53 19.44 0.480 Total DM g/m2 2084 1897 2008 1823 2134 2086 154

This joint study between Charles Sturt University and the University of Sydney has established strong links with The University of Adelaide, Waite Institute and the International Rice Research Institute in Los Banos. The collaboration has led to modifications to the dehulling equipment so that rice grain from these trace element studies can be processed without Fe and Zn contamination.

Future plans The findings from this field study will be published and the findings compared to those from the genotype studies of Mr Robert Duncan (Project 2301) and from the International Rice Research Institute.

2.4 Sustainable crop protection

Sub-Program Leader: Dr Ric Cother NSW Agriculture Orange

Biological control of insects and weeds has a long lead-time because there are many intertwined disciplines at play. Modifying existing practices and incorporating a biological control phase will ensure sustainability of pest control.

Host range and virulence of Rhynchosporium alismatis (2401)

Project Leader: Dr Ric Cother NSW Agriculture Orange

Outcomes Sequencing of internal transcribed spacer (ITS) regions of a large number of fungal isolates revealed close relationships between R. alismatis and the teleomorph genus Plectosphaerella

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as well as several anamorphic fungi including species of Verticillium and Nectria. Intraspecific variation in R. alismatis was minimal. The genetic structures of populations of R. alismatis also displayed minimal variation with low to moderate levels of gene diversity across three geographically isolated populations. The average genetic distance and overall population differentiation were also small. However, measures of both genotypic and allelic diversity were significant between populations. Population structures appeared clonal supplemented with intermittent rounds of recombination or gene flow over considerable distances. Migration via infected seed and/or plant material transported by irrigation channels and watercourses is probable. However, little evidence for gene exchange was apparent and evolution of pathogenic ability was minimal. Further investigation of the infection process of the fungus on target weeds indicated that the rates of conidial germination and appressorium formation on these species were almost identical to that of A. plantago–aquatica, a known host. Germ tube elongation and appressorium formation occurred randomly over the leaf surface with no apparent stimulus and the fungus entered the host by way of direct penetration facilitated by the production of a penetration peg. Holes left by penetration pegs, 0.25–0.5 µm in diameter, were observed by scanning electron microscopy on both A. plantago–aquatica and S. graminea following the removal of appressoria. However, no penetration of S. montevidensis was witnessed and penetration sites on S. graminea were accompanied by evidence of host defence responses.

Improving crop protection (2403)

Project Leader: Dr Ric Cother NSW Agriculture Orange

Dr Cother undertook a four-week study tour of the southern States of USA and California in July-August 2002 looking at diseases of rice. It was clear that while some diseases will not pose a major threat to the Australian rice industry because of our dry climate, others (especially Bakanae) will be of major concern if introduced. The awareness created by this trip, the work of Vincent Lanoiselet in Project 2409 and recent events in the Riverina indicate that diseases will have a greater impact on yields in future.

Biodiversity assessment of MIA rice fields using stable isotope analysis (2404)

Project Leader: Dr Mark Stevens NSW Agriculture Yanco

Dr Andrea Wilson conducted this project as a component of her PhD study on the influence of crop management strategies on invertebrate biodiversity. Dr Wilson had her thesis accepted by Charles Sturt University in March 2003, and is now employed as an Associate Lecturer at the Wagga Wagga campus of CSU.

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Dr Wilson looked at three categories of rice crops, conventional aerially-sown (CAS), conventional drill-sown (CDS), and organic drill-sown (ODS). She found major differences in biodiversity parameters shortly after sowing, with CAS crops showing the least biodiversity, and ODS crops the highest. As the season progressed, crops in the three different groups became increasingly similar, and sophisticated multivariate analysis was necessary to demonstrate differences between invertebrate communities in the later part of the growing season. Stable isotope analysis showed that food web structure was also affected by crop management strategies. CAS crops had poorly defined food web relationships, whilst the ODS crops showed evidence of more complex trophic relationships. As with the invertebrate communities themselves, trophic relationships became more similar as the season progressed.

Conservation biology of the Southern Bell Frog in irrigation areas (2408)

Project Leader: Prof Alistar Robertson/Ms Skye Wassens Charles Sturt University Wagga Wagga

Objectives Declining biodiversity in rice growing areas is of great concern to land managers and rural communities. This project aims to create a framework for the integration of threatened species management and biodiversity conservation into successful rice growing practices. The project focuses on the Southern Bell Frog (Litoria raniformis), one of a number of threatened species that inhabits rice-growing areas in NSW.

Progress * Radio tracking studies, which aimed to identify key Southern Bell Frog habitats within rice

growing areas, were completed in May 2003. * Demographic studies of local populations in the Coleambally Irrigation Area were also

completed in May 2003. * A study of the influence of water quality and vegetation cover on breeding successes was

completed in April 2003. * Genetic analysis of tissue samples is expected to commence in July 2003.

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Southern Bell Frog with transmitter.

Stem diseases in rice in south-eastern Australia (2409)

Project Leader: Dr Gavin Ash Charles Sturt University Wagga Wagga

Objectives This study is being conducted by Mr Vincent Lanoiselet as part of his PhD project at Charles Sturt University. The aim of the project is to investigate current diseases of rice with a focus on aggregate sheath spot and sheath spot.

Progress Aggregate sheath spot (caused by Rhizoctonia oryzae-sativae) and sheath spot (caused by R. oryzae) were first reported in Australian rice crops just two years ago. While aggregate sheath spot was known to be an important disease, sheath spot was dismissed as being of minor importance. An extensive survey showed that both diseases were present and well established in all rice growing areas except the Lachlan Valley. In the Murrumbidgee Irrigation Area more than 60% of bays inspected were infected, in the Coleambally Irrigation Area the figure was closer to 55% and in the Murray Valley one or both of the diseases showed up in more than 40% of the inspected bays. A field trial conducted at the Yanco Agricultural Institute in 2002/2003 showed that each of the diseases has the potential to cut yields of the rice variety “Langi” by 10%. These diseases could therefore be robbing growers of as much as $260 to $290 per hectare and reducing water use efficiency by around 1.5 megalitres per hectare. Two fungicides were used in this trial and both of them reduced disease severity but did not increase yield significantly. Fungicide application timing and varietal susceptibility will be investigated next year.

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Finally, a new disease has been identified in 2002 caused by Sclerotium hydrophilum.

Rice diseases field trial at Yanco Agricultural Institute

2.5 Economics (This Sub-Program relates to projects across all of the CRC’s Programs).

Evaluation of alternative resource management strategies in a risky environment (6201)

Project Leader: Dr Rajinder pal Singh NSW Agriculture Yanco

Objectives This project aims to evaluate a selection of Rice CRC research and extension projects against economic and physical dimensions of sustainability. The project involves analysing the impact of selected CRC technologies at the farm and regional levels. This will identify changes in farm and regional incomes and changes in physical dimensions of sustainability such as soil and water salinity, and watertable depths.

Progress A summary of analysis of three CRC projects evaluated is provided. * Economic analysis of improving cold tolerance in rice in Australia

The occurrence of low night temperatures during reproductive development is one of the factors most limiting rice yields in southern Australia. Yield losses due to cold temperature are the result of incomplete pollen formation and subsequent floret sterility. Researchers have found that in 75% of years, rice farmers suffer losses between 0.5 and 2.5 t/ha. Research is being undertaken to identify overseas rice varieties that are cold tolerant under the local weather conditions and, by using those genotypes as parent material, develop cold tolerance varieties of rice.

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A yield simulation model was used to measure reduction in losses due to cold at different minimum threshold temperatures, while the SAMBOY Rice model was used to measure the costs and returns of a breeding program for cold tolerance. The results of the economic analysis reveal that new cold tolerant varieties would lead to significant increase in financial benefits through reduction in losses due to cold, and an increase in yield from the better use on nitrogen by the cold tolerant varieties. The returns to investment on the research project are estimated to be high. * Analysing the benefits of growing crops after rice in the rice growing areas in Australia Rice is the most important crop on broad acre farms in the south-west of NSW. Although rice growing has brought prosperity to the region, its intensive cultivation has also led to serious problems of rising watertables, waterlogging and irrigation salinity. In most of the rice growing areas, the watertables are around 2 m below the surface. If unattended this would be a serious threat to irrigated agriculture in these regions with associated problems of poor water quality downstream. The Rice CRC has funded research Project 1205, “Quantifying and maximising the benefits of growing crops after rice”, to encourage the growing of wheat straight after the rice phase to improve the productivity and water use efficiency of the rice wheat cropping system. The economic analysis of this project indicates that growing crops after rice not only leads to more efficient use of water but also provides some financial and environmental benefits. From the industry’s viewpoint the benefit-cost ratio of the project was in the range of 5.3 to 7.3 and from the community’s viewpoint in the range of 6.0 to 8.6. * Valuing a test for nitrogen status in rice Scientists working in a Rice CRC funded project are trying to develop a nitrogen (N) test for soils of rice paddocks that would determine the amount of N available in the soil and how much more is required to meet the plant N requirements. The results reveal that the information provided by the new soil test is valuable as it helps farmers to use N more profitably. The findings of the benefit cost analysis show that the benefits at the current accuracy levels are sufficient to meet the total costs of research for developing the test. The results were achieved for one scenario, i.e. - value of the soil-based near infrared (NIR) test under average weather and deep water conditions. To measure the full impact of the new research, the study needs to be extended to consider a range of weather conditions and paddock histories. Further the benefits would be quite significant, if the scientists are able to increase the accuracy of the test from 70% to 94 %, i.e. - at par with the accuracy levels of the existing NIR panicle initiation (PI) test.

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MILESTONES Milestone Year 4 Year 5 Year 6 - 2002/2003 Yr 7 2.1 Soil chemical & physical properties Appointment of post doctoral fellow Development of N soil test X ü Extended X ü Extended Appointment of technical officer Soil acidity problem definition X ü Definition of soil property damages X ü X ü Continuing Xü X Evaluation of aerial video as a tool X ü X ü Continuing Xü X Definition of management factors affecting nutrient recovery X ü X ü Xü X PhD project - spatial analysis X ü X ü Continuing X Continuing X 2.2 Environmental change Appoint research scientist Define flowering test for cold resistance Confirm tolerance under field conditions X ü X ü Continuing ü Student projects X ü Understanding cold and Nitrogen interaction X ü X ü ü Lipid metabolism X Redefined Understanding cellular response to cold X ü ü Application of cold studies X ü X ü Xü X Studies on climate change X ü X ü Xü Program 1 X 2.3 Mineral nutrition Appointment of staff X ü Appointment of student X ü Review of factors affecting yield and quality Development of techniques Assess mineral changes ü Assess impact of yield improvement and management changes on mineral/quality relationships in rice and its relatives X ü Modified X ü Extended Xü X Determine mechanisms influencing translocation of mineral to grain X ü X ü Continuing Xü X Modify factors influencing quality in intensive rice growing X ü X ü Continuing Xü X 2.4 Sustainable crop protection Appointment of PhD student X ü Appointment of honour students X ü Biology of Arrowhead and Water Plantain Better understand biocontrol Identification of dominant bloodworm species Develop lab techniques for at least 1 additional Chironomid X ü Evaluate Bti* transgenic lines X ü X ü Continuing Xü X Allelopathy Progress towards identification of allelochemicals Improved pathogenicity of R.alismatis to Alismataceous weeds X ü X ü Continuing Xü X Phenology and host specificity of bloodworm species defined X reallocated X ü Continuing Xü X Integration of chemical and biological management of weeds X ü X ü Continuing Xü X Determination of susceptibility of major cultivars to exotic pests and diseases X ü X ü Continuing Xü X

*Bti= Bacillus thuringiensis, a bacterium with insecticidal properties. X = To be completed (in some cases this exercise is spread over several years). ü= Achieved (if not achieved, status provided). NB: After obtaining approval from the CRC Secretariat, comments on milestones for Years 1 to 3 inclusive have been removed from this table. Please refer to previous Rice CRC Annual Reports if you wish to view this information or contact the Rice CRC for additional information.