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Wednesday, August 27, 2014

New Research Building

California Cooperative Rice Research Foundation, Inc.

University of California

United States Department of Agriculture Cooperating

Rice Experiment Station P.O. Box 306, Biggs, CA 95917-0306

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About the Cover

A new research building funded by the California Cooperative Rice

Research Foundation was completed and dedicated in December

2013. The metal building includes a storage area for the research

combines and planters, a milling lab, seed processing area, a sample

cleaning and drying room, research assistant offices, mezzanine

storage, men’s and women’s bathrooms with showers and a staff

meeting/break room. The project included instillation of a septic

system to serve the entire Rice Experiment Station and an expanded

concrete service area. Field day lunch will be served from the new

facility.

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California Cooperative Rice Research Foundation, Inc.

Board of Directors

Sean Doherty, Dunnigan (Chairman)

Bert Manuel, Yuba City (Vice-Chairman)

Gary Enos, Glenn (Treasurer)

Steve Willey, Nicolaus

Carl Funke, Willows

Aaron Scheidel, Pleasant Grove

Charlie Mathews, Jr., Marysville

Peter Panton, Pleasant Grove

Dennis Spooner, Willows

Gary Stone, Richvale

Lance Benson, Durham

Rice Experiment Station Staff

Administrative

Kent S. McKenzie, Ph.D., Director

Lacey R. Stogsdill, Administrative Assistant

Pamela L. Starkey, Administrative Assistant

Rice Breeding Program

Virgilio C. Andaya, Ph.D., Director of Plant Breeding

Farman Jodari, Ph.D., Plant Breeder, Long Grains

Stanley O. P.B. Samonte, Short & Premium Medium Grains

Jeffrey J. Oster, M.S., Plant Pathologist, Disease Resistance

Cynthia Andaya, Ph.D., Research Scientist

Matthew Calloway, Breeding Nursery Manager

Baldish K. Deol, Plant Breeding Assistant

Ravinder Singh Gakhal, Plant Breeding Assistant

Christopher Putz, Plant Breeding Assistant

Davinder Singh, Plant Breeding Assistant

George Yeltatzie, DNA Lab Technician

Field Operations and Maintenance

Burtis Jansen, Field Supervisor

Joe Valencia, Mechanic and Operator

Randy Jones, Maintenance and Operator

Shane Odekirk, Maintenance and Operator

UC Rice Research

J. Ray Stogsdill, Staff Research Associate II

Kevin Goding, Staff Research Associate II

Steve Johnson, Staff Research Associate I

Whitney Brim-DeForest, Ph.D. Candidate

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2014 Rice Field Day Program

7:30—8:30 Registration and Poster Viewing

Posters and Demonstrations

1. Rice Waste Discharge Requirement: Pesticide Monitoring

Requirements Under the Order (California Rice Commission)

2. Rice Pesticide Program- Thiobencarb Monitoring Results and

Outcomes (California Rice Commission)

3. Thiobencarb Management Practices & Permit Conditions per

DPR Enforcement Compendium (California Rice Commission)

4. Rice Pesticide Use Matrix (California Rice Commission)

5. Herbicide Resistance Stewardship Chart and Handout

(California Rice Commission)

6. Can The Red Shouldered Stink Bug Cause Pecky Rice? (L. Espino

and L. Godfrey, UCCE)

7. The Effect of Silicon Fertilization on Performance of Rice Against

Rice Water Weevil (Lissorhoptrus oryzophilus Kuschel) M.A.

Aghaee and L.D. Godfrey, UCD &UCCE)

8. Target-Site Resistance To Propanil In Cyperus Difformis L.

(Smallflower Umbrella Sedge): Implications For Management In

Rice Fields Of California (R.M. Pedroso, R. Alarcon-Reverte, A.J.

Fischer, UCD)

9. Weed Population Dynamics In Alternative Irrigation Systems (W.

Brim-DeForest, B.A. Linquist, A.J. Fischer, UCD)

10. Differentiation Of Leptochloa Fusca Spp. Fasicularis And

Uninervia (Sprangletop) (F.L. Borghesi, W. Brim-DeForest, A.J.

Fischer, UCD)

11. Resistance Of Leptochloa Fusca Spp. Fasicularis (Sprangletop) To

Clomazone And Accase Inhibitors(W. Brim-DeForest, A.J.

Fischer, UCD

12. Dynamics of Weed Emergence In California Rice Systems (W.

Brim-DeForest, R. Pedroso, UC Davis; L. Boddy, Marrone Bio

Innovations; B.A. Linquist, A.J. Fischer, UCD)

13. Combining Genetic Resistance to Blast, Stem Rot and Sheath

Spot (J. Oster, V. Andaya, C. Andaya, K.S. McKenzie, F. Jodari,

S.O.P.B. Samonte, RES)

14. Disease Symptom Posters (J.J. Oster, RES)

15. Development And Performance Of Blast Resistant Near-Isogenic

Lines Of Rice In M-206 Genetic Background (V.C. Andaya, J.J.

Oster, C.B. Andaya, F. Jodari, S.O.P.B. Samonte, and K.S.

McKenzie)

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16. Combining Genetic Resistance to Blast Stem Rot and Sheath

Spot. (J. Oster, V. Andaya, C. Andaya, K.S. McKenzie, F. Jodari,

and S. O.S.P.B Samonte, RES)

17. California Rice Breeding: Yield Increase Rate Due To Semi-Dwarf

Varietal Releases By The Rice Experiment Station (S.O.P.B.

Samonte, V.C. Andaya, F. Jodari, J.J. Oster, C.B. Andaya, and

K.S. McKenzie)

18. Using Alternative Water Management to Reduce Greenhouse Gas

Emissions and Maintain Yields in California Rice Systems. (G.

LaHue, M.A.A. Adviento-Borbe, C. van Kessel, J.R. Stogsdill, and

B.A. Linquist, UCD & UCCE)

19. Do Nutrient Management Practices That Improve N Use

Efficiency Reduce Greenhouse Gas Emissions In Flooded Rice

Fields? (A. Adviento-Borbe, M. Anders, C. Pittelkow, B. Linquist,

and C. van Kessel, UCD &UCCE)

20. Modeling of Rice Response to Temperature and Photoperiod for

CA Major Rice Varieties (H. Sharifi, R. Mutters, C. Greer, L,

Espino, R.J. Stogsdill, R. Wennig, R. Hijmans, C.V. Kessel, J.

Hill, B. Linquist UCD &UCCE)

21. The Effect of Biochar on Rice Seed Germination, Early Seedling

Vigor, and Post Flood Plant Development (R. Green, Benchmark

Development and S. Hughes, Charganics)

22. Identification Of Novel Low Phytic Acid Mutants In Rice Using

Reverse Genetics (S.I. Kim and T. H. Tai)

23. Identification Of Mutations In Genes Encoding Two Major Rice

Allergens Using TILLING By Sequencing (A. Chun, D. Burkart-

Waco, and T. H. Tai, USDA-ARS & UCD)

24. Development Of Molecular Markers For Evaluation Of Low

Temperature Germ Inability And Seedling Cold Tolerance In Rice

Germplasm (D.Y. Hyun, G.A. Lee, M. J. Kang, M. C. Lee, J. G.

Gwag, Y.G. Kim, D. Burkart-Waco, S.I. Kim, and T. H. Tai,

USDA-ARS & UCD)

25. Extending Shelf Lives Of Rough And Brown Rice Using Infrared

Radiation Heating (C. Ding, R. Khir, Z. Pan, and K. Tu USDA-

ARS & UCD)

26. Impact Of Infrared Heating On Physicochemical Properties Of

Rice Under Accelerated Storage Conditions (C. Ding, R. Khir, Z.

Pan, K. Tu, USDA-ARS & UCD)

27. Effective Disinfection Of Rough Rice Using Combined Pulsed

Ultraviolet Light And Holding Treatment (B. Wang, R. Khir, Z.

Pan, N. Mahoney, USDA-ARS & UCD)

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28. The Contribution of Sacramento Valley Rice Systems to

Methylmercury in the Sacramento River (C. Tanner, L.

Windham-Myers, J. Fleck, K. Tate, S. McCord, and B. Linquist,

UCD,USGS & UCCE)

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8:30 - 9:15 a.m. GENERAL SESSION

Welcome by Sean Doherty, Chairman, CCRRF

CCRRF Business Meeting

Financial Report, Gary Enos, Treasurer, CCRRF

Directors Nomination Committee Report,

Kent McKenzie, RES

Rice Research Trust Report, Steve Willey, Chairman, RRT

California Rice Research Board Report,

Seth Fiack, Chairman, CRRB

California Rice Industry Award Presentation, Bert Manuel

Vice Chairman, CCRRF

9:20 - 10:45 a.m. MAIN STATION TOUR

Two tours occur simultaneously and repeat.

Blue & Green Groups to Trucks

Rice Variety Development

(V.C. Andaya, F. Jodari, S.O. Samonte, and J.J. Oster, RES)

Fifteen Years of Pyrethroid Insecticide Use in Rice – Are These

Products Still Effective? Are There Viable Options Nearing

Registration? What Is the Future of IPM of Rice Invertebrate Pests? (L. Espino, L.D. Godfrey K. Gooding, M. Aghaee, UCCE & UCD)

10:30 - 10:45 a.m. Refreshments - New Warehouse

10:45 - Noon Repeat Station Tour with

Red & White Groups

9:20 - 10:45 a.m. HAMILTON ROAD TOUR

Two tours occur simultaneously and repeat.

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Red & White Groups to Buses

Rice Weed Control: Herbicide Programs, New Chemicals, and Weed

Management

(A.J. Fischer, W. Brim-DeForest, R. Alarcon-Reverte, R. Pedroso, B.A.

Linquist, C. Greer, L. Espino, R.G .Mutters, J.E. Hill, S. Johnson, and

J.R. Stogsdill, UCD & UCCE)

10:30 - 10:45 a.m. Refreshments – Research Building Canopy

10:45 - Noon Repeat Hamilton Road Tour with

Blue & Green Groups

Noon Luncheon Concludes Program

Lunch will be served in the New Research Building and with seating

at the tables on the lawns under the canopies

2.0 hours of Continuing Education credit for this 2014 Rice Field Day

has been granted from Cal/EPA Department of Pesticide Regulation

Disclaimer

Trade names of some products have been used to

simplify information. No endorsement of named

products is intended nor is criticism implied of similar

products not mentioned.

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Introduction By Sean Doherty

On behalf of the Board of Directors, staff and UC cooperators,

welcome to Rice Field Day 2014. Field Day is our annual opportunity

to highlight the research that is at underway the Rice Experiment

Station for the California Rice Industry. It is also the annual business

meeting for the grower/owners of the California Cooperative Rice

Research Foundation.

2014 has certainly proved to be a year of “uncertainty” for the

California rice industry as I am sure all of you have experienced. I am

pleased to report that we have been able to continue our breeding and

research activities without any reduction. This has been possible

with the continued financial support from the California Rice

Research Board as well as the Foundation and the Rice Research

Trust. RES does have a productive well drilled in 1978, that has been

tested and available if needed. I would like to acknowledge the

support we have received from the Richvale Irrigation District and

other waters districts in recognizing our critical role in California

rice.

The highlight of the day is the field tours where you are able to hear

from the researchers and see the nurseries on the main station as

well as weed control research at the Hamilton Road site. Dr. Virgilio

“Butz” Andaya, Director of Plant Breeding, is overseeing the medium

grain program and will be reporting on that project. Dr. Farman

Jodari will update you on his long grain program and varieties. Dr.

Stanley Samonte will present his work on premium quality and short

grain varieties. Rice Experiment Station Pathologist Jeff Oster

continues his work on rice diseases and will be speaking to you at his

rice disease nursery. Dr. Luis Espino, UC Cooperative Extension

Farm Advisor will also present the ongoing work on rice insect pests

on the main station tour.

Dr. Albert Fischer, UC Davis Professor, will be leading you on a

walking tour of the weed research nursery at the Hamilton Road site.

Dr. Cynthia Andaya and Mr. George Yeltatzie have our DNA marker

lab in full operation to support the RES Breeding Program.

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The Rice Experiment Station remains committed to the production of

clean, weed and disease free foundation seed for the California rice

growers. We continue work in cooperation with the Foundation Seed

and Certification Services and the California Crop Improvement

Association. The certified seed program is an essential part of

maintaining genetic purity in our varieties and insuring the highest

quality seed is available to the industry. The seed program is self

supporting and is not funded by the Rice Research Board. Total

acreage in seed production was reduced about 20% this year, by

rotation into available smaller fields, but no varieties were dropped

and two experimentals lines are under increase.

I would like to acknowledge the many businesses and growers who

support Rice Field Day through financial donations, agro chemicals

and use of trucks for our tours. This year we have also included

equipment displays from several sponsors. This industry support is

very important to the success of the Field Day. The supporters are

listed in your program and we thank them again for their assistance.

Thank you for attending Rice Field Day and supporting our research

programs. If you have any questions about Field Day or the Rice

Experiment Station, please take the opportunity to talk with the

Directors and staff. There is a great deal of useful information on

display today and I invite you to visit the displays and posters as well

as the field tours.

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D. Marlin Brandon Rice Research Fellowship In 2000, a memorial fellowship was established to provide financial

assistance to students pursuing careers in rice production science and

technology as a tribute to Dr. D. Marlin Brandon, past Director and

Agronomist at the Rice Experiment Station. The California Rice

Research Board made a one-time donation to the Rice Research Trust

of $52,500 with $2,500 used for the 2000 fellowship. The Rice

Research Trust contributed an additional $50,000 and established a

fellowship account. Interest from investments on the $100,000

principal is used to provide grants to the D. Marlin Brandon Rice

Scholars. Twenty-two fellowships have been issued from 2000 to

2011.

Beginning in 2012 some changes were made to offer more financial

support with two-year fellowship in the amount of $10,000 to

encourage an undergraduate to pursue graduate study in rice

research. This effort not been successful and the Board has decided to

return to offering the previous annual fellowships. Application

materials are available by contacting the Rice Experiment Station.

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SUBMITTED POSTER ABSTRACTS

CALIFORNIA RICE BREEDING: YIELD INCREASE RATE

DUE TO SEMI-DWARF VARIETAL RELEASES BY THE RICE

EXPERIMENT STATION

S.O.P.B. Samonte, V.C. Andaya, F. Jodari, J.J. Oster, C.B. Andaya,

and K.S. McKenzie, RES

Rice productivity per unit area has been increasing over the years.

This has been attributed to better management practices, such as for

soil fertility, water, insect pests, diseases, and weeds, and also to

improved rice varieties. Rice grain yields in California are the highest

in the United States and these have increased from 4775 lb/acre in

1960 to 8350 lb/acre in 2011 based on USDA-ERS data published in

2012.

The primary mission of the California Cooperative Rice Research

Foundation, Inc., (CCRRF) Rice Experiment Station (RES) in Biggs,

CA, is to develop improved rice varieties for all grain and market

types and to sustain high and stable grain yield and quality with

minimum environmental impact for the benefit of California rice

growers. The objective of this study was to determine the grain yield

increase rate due to semi-dwarf varieties released by the Rice

Experiment Station from the 1970s to the 2000s.

In 2012, 25 semi-dwarf varieties (conventional long, medium, and

short grain types) released by RES were planted at two sites within

the station. These included L-206, M-205, M-206, and S-102, which

produced mean grain yields of 10,570, 10,650, 10200, and 9440

lb/acre, respectively, in Statewide Yield Trials at RES in 2012.

Planting was done by wet-seeding in site 1 and drill-seeding in site 2.

Data on grain yield and yield-related traits were measured. The RES

Field Day poster, however, focuses on the grain yield trends. The

second year of this study is being conducted in 2014, and the

combined 2012 and 2014 data will be analyzed.

Grain yields differed significantly among varieties, ranging from 8091

lb/acre for Calrose-76 to 10,740 lb/acre for M-206. Varietal releases

have increased grain yields significantly. Grain yield increase rate

due to varietal releases was estimated at 54 lb/acre/year. This rate,

however, is a preliminary estimate based on one year’s data. To

account for common genotype x environment interactions that occur

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in yield trials, a second year of experiments is being conducted in

2014. Results from this study will not only be useful in analyzing past

varieties, but will also be useful in planning and breeding rice for the

future.

DEVELOPMENT AND PERFORMANCE OF BLAST

RESISTANT NEAR-ISOGENIC LINES OF RICE IN M-206

GENETIC BACKGROUND

V.C. Andaya, J.J. Oster, C.B. Andaya, F. Jodari, S.O.P.B. Samonte,

and K.S. McKenzie, RES

The Rice Experiment Station (RES) located in Biggs, California,

initiated a project to develop near-isogenic rice lines (NILs)

containing different resistance genes to rice blast (Magnaporthe

grisea) in the genetic background of M-206, a temperate Japonica

medium grain variety. M-206, a commercial rice variety, is a popular

and widely grown variety in the Sacramento Valley and is susceptible

to rice blast. Ten blast resistance genes (Pi genes) were used in the

gene introgression, namely, Pi1, Pi2, Pi9, Pi33, Pi40, Pib, Pikh, Pikm,

Pita2, and Piz5.

Gene introgression was performed using at least seven backcrosses to

M-206 using biological screening initially, followed by marker-

assisted backcrossing using PCR-based DNA markers. Supplemental

blast screening was performed to verify presence of resistance genes

in plants used for crossing. The NILs were advanced to homozygosity

and given individual designation that specifies the cultivar used and

the resistance gene introgressed (e.g. M-206+Pi33). The agronomic

and yield performance of the NILs, M-206, and check varieties were

evaluated in replicated field experiments at RES in 2013. Seven of

the NILs were also included in select locations of the Statewide Yield

Test in 2012 and 2013.

This poster describes the development of the NILs and their

performance in comparison to M-206 in terms of a number of

agronomic and grain traits. It will also report if there are negative or

positive effects of individual blast resistance genes to these measured

traits.

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DO NUTRIENT MANAGEMENT PRACTICES THAT IMPROVE

N USE EFFICIENCY REDUCE GREENHOUSE GAS

EMISSIONS IN FLOODED RICE FIELDS?

M.A.A. Adviento-Borbe, M. Anders, C. Pittelkow, B. Linquist and

C. van Kessel, Dept. of Plant Sciences, UCD

Irrigated rice fields release to the atmosphere significant amounts of

CH4 and N2O and fluxes of these greenhouse gases (GHG) can be

reduced by managing efficiently the N fertilizer inputs during the

growing season. Field studies were conducted to evaluate the effects

on CH4 and N2O emissions of the different N fertilizer management

practices that aimed to increase N use efficiency and reduce GHG

emissions in irrigated lowland rice systems in California and

Arkansas. Rice yield and GHG emissions were determined from drill

seeded (AR, CA1, CA2; 84-70 kg seed ha-1) and wet seeded (CA3, CA4;

224 kg seed ha-1) farmer’s and experimental fields fertilized with

various N fertilizer sources such as aqua ammonia, urea, polymer

coated urea (Agrotain™), and ammonium sulfate at recommended N

rates ranging from 100-168 kg N ha-1. These N fertilizers were

applied either broadcast or subsurface once or twice during the rice

growing period. Emissions of CH4 and N2O were measured

throughout the rice crop cycle using flux chamber and gas

chromatography method. At all sites, grain yields were 3.5 to 6.2 Mg

ha-1 without N fertilizer application. The addition of N fertilizer

increased yield by approximately 113% with no consistent trends

among N sources, number and depth of N fertilizer applications.

Fertilizer use efficiency ranged from 17 to 64% with the highest in

wet seeded fields. In all locations, different types of N fertilizer had

no effect on annual CH4 and N2O emissions however, magnitudes of

CH4 and N2O emissions were 1.5 and 1.8 times higher with N

application compared with unfertilized treatments (81 kg CH4-C and

0.56 kg N2O-N ha-1 yr-1) , respectively. There were no clear patterns

whether application of different N fertilizer sources (urea, polymer

coated urea, ammonium sulfate, aqua N) effectively decreased global

warming potentials (GWP) because annual GWP were variable in all

sites. Yield-scaled annual GWP tended to decrease in split N fertilizer

treatments but this was not consistent across sites. Our results show

that N management practices that improve fertilizer use efficiency

such as crop-specific urea fertilization, using slow-release fertilizer,

inhibitors, or injected aqua N may have potential to reduce GHG

emissions but require further assessment.

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MODELING OF RICE RESPONSE TO TEMPERATURE AND

PHOTOPERIOD FOR CA MAJOR RICE VARIETIES.

H. Sharifi, R. Mutters, C. Greer, L, Espino, J.R. Stogsdill, R.

Wennig, R. Hijmans, C. van Kessel, J. Hill, B. Linquist UCD & UCCE

The development of rice is affected by temperature and photoperiod

sensitivity. The ability to predict developmental stages is essential for

efficient rice crop management. Management decisions--which are

often based on crop development--can significantly affect yield and

profitability. This research aims to develop a model that accurately

predicts important growth stages for rice to enable farmers to

improve management decisions.

To achieve this objective we use historical data from region-wide

variety trials and additional data from field and greenhouse trials to

(i) quantify the effect of air temperature and photoperiod sensitivity

on rice development and (ii) develop a predictive model of the

principal growth stages of rice, including panicle initiation (PI),

heading (H), and physiological maturity (PM).

Nine major CA rice varieties were selected for this study: M-104, M-

105, M-202, M-205, M-206, M-401, CM101, S-102, and L-206. These

varieties were chosen to represent a range of photoperiod, crop

duration, and grain size. Historical data was obtained from

University of California Cooperative Extension (UCCE) Rice Variety

Evaluation tests (RVE) 2000-2013 for all varieties. Field trials (2011-

current) supplement the RVE data. A greenhouse study at University

of California Davis Vegetable Crops facility complements field data

by permitting more precise observation of photoperiod sensitivity

effect by way of staggered planting dates and a controlled

temperature environment.

The preliminary results of the greenhouse study indicate two groups

of varieties based on their response to photoperiod: photoperiod

sensitive (M-401) and photoperiod non-sensitive (CM101, M-104, M-

105, M-202, M-205, M-206, S-102 and L-206) varieties. Thermal-time

model was developed to predict the time to PI, H, and PM stages.

Historical, field, and greenhouse data were used to calibrate and

validate the models. Except for M-401, Thermal time model

accurately predicts the time to all stages for varieties in this study.

This is further supported by preliminary results from our greenhouse

study.

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This model will be used to develop a unique predictive tool for

California (CA) rice farmers that will help them make more informed

management decisions throughout rice crop development.

USING ALTERNATIVE WATER MANAGEMENT TO REDUCE

GREENHOUSE GAS EMISSIONS AND MAINTAIN YIELDS IN

CALIFORNIA RICE SYSTEMS

G. LaHue, M.A.A. Adviento-Borbe, C. van Kessel, J.R.

Stogsdill, and B. A. Linquist Dept. of Plant Sciences, UCD & UCCE

Rice has traditionally been grown under continuously flooded

conditions in California, which has allowed growers to achieve high

grain yields, use irrigation water efficiently, and maintain high

nitrogen use efficiency (NUE). Recently however, there has been

some concern that these anaerobic growing conditions may cause

problems such as high methane (CH4) emissions, arsenic (As) uptake

by rice plants, and methyl-mercury formation. Studies in other rice-

growing regions have shown that the alternation of wet (flooded) and

dry (drained) growing conditions (referred to as AWD) has the

potential to mitigate the aforementioned problems. While it is

possible that conventional water management will continue to be the

standard practice in California, it is important to evaluate the

agronomic viability of AWD in California and prepare for scenarios

where growers might face legislative pressure to implement

alternative water management strategies.

In this study, nitrous oxide (N2O) and CH4 emissions from three

water management treatments were compared: water-seeded rice

grown with continuous flooding (WS-C); water-seeded rice grown

under flooded conditions until canopy closure and then flush-irrigated

(WS-AWD); and drill-seeded rice grown with flush-irrigation (DS-

AWD). The three treatments were also compared for rice grain yield

and N response. The WS-AWD treatment reduced CH4 emissions by

over 50% and the DS-AWD treatment cut CH4 emissions by almost

90% relative to the WS-C treatment. In contrast, N2O emissions were

the highest in the DS-AWD treatment and did not differ significantly

between the WS-AWD and the WS-C treatments, although N2O

emissions were < 1% of the total Global Warming Potential (GWP)

during the growing season. The total GWP (kg CO2 eq ha-1 season-1)

was therefore lowest in the DS-AWD treatment and highest in the

WS-C treatment. Rice grain yields and N response were not

significantly different among the three water management

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treatments. Alternative water management therefore represents a

promising alternative to allow California rice growers to maintain

rice grain yields and N-use efficiency while significantly decreasing

greenhouse gas emissions. However, more research is needed on

AWD to confirm these findings and to evaluate both its economic

viability and its potential for large-scale applications.

EXTENDING SHELF LIFE OF ROUGH AND BROWN RICE

USING INFRARED RADIATION HEATING

C.Ding1,3 R. Khir1,4 Z. Pan1,2 K. Tu3 1 Department of Biological and Agricultural Engineering, UCD 2 Healthy Processed Foods Research Unit, Western Regional Research

Center, USDA 3College of Food Science and Technology, Nanjing

Agricultural University, 4 Department of Agricultural Engineering

The objective of this study was to investigate the effect of IR heating

and tempering treatments on storage stability of rough and brown

rice. Samples of freshly harvested medium grain rice variety M-206

with initial moisture content of 25.03±0.21% (d.b.) were used. The

samples were dried using infrared (IR), hot air (HA) at 43°C and

ambient air (AA) for comparison. For IR drying, rice was heated to

temperature of 60 °C under radiation intensity of 4685 W·m-2,

followed by 4-h tempering and natural cooling. The dried samples

were divided into two portions which were respectively used as rough

and brown rice for storage at 35±1 °C with relative humidity of 65±3%

for ten months. The drying characteristics and milling quality of rice

were determined. Free fatty acid, peroxide value and iodine value

were measured to detect any notable degradation of lipids in rough

and brown rice during storage. High heating and drying rates of rice

were achieved under IR heating. It took only 58 s to heat rough rice to

temperature of 60 °C with corresponding moisture removal of 2.17

percentage points during IR heating. The total moisture removal

after natural cooling reached to 3.37 percentage points without

additional energy input. IR drying did not show any adverse effects

on milling quality of dried rice. Additionally, it resulted in an

effective inactivation of lipase and consequent improvement in the

long-term storage stability of rough and brown rice. It is concluded

that the improvement in rough and brown rice stability during

storage can be achieved through drying rough rice using IR heating to

temperature of 60°C followed by tempering for 4 h and natural

cooling. IR drying provides a potential to store brown rice instead of

rough rice with extended shelf life and reduced cost.

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IMPACT OF INFRARED HEATING ON PHYSICOCHEMICAL

PROPERTIES OF RICE UNDER ACCELERATED STORAGE

CONDITIONS

C. Ding1,4, R. Khir1,2, Z. Pan1,3, K. Tu4 1Department of Biological and Agricultural Engineering, University

UCD, 2 Department of Agricultural Engineering, Faculty of

Agriculture, Suez Canal University,3 Healthy Processed Foods

Research Unit, USDA-ARS-WRRC4 College of Food Science and

Technology, Nanjing Agricultural University

Infrared (IR) radiation heating has shown a great potential to achieve

high drying rate, good milling quality of rough rice and effective

stabilization of rice bran. However, further study on the effect of IR

on physicochemical prosperities of rice during storage is needed. The

aim of this research was to characterize the changes in pasting,

thermal and cooking properties of infrared dried rice during storage.

Freshly harvested medium grain rice (M-206) with moisture content

of 20.0 ± 0.2% (w.b.) was used for this study. The samples were

divided into three potions and dried using infrared (IR) heating, hot

air (HA) and ambient air (AA). For IR heating, the samples were

heated to temperature of 60 °C using a catalytic emitter under

radiation intensity of 5348 W/m2 followed by 4 h tempering and

natural cooling. All of the dried rice samples were stored at 35 ºC for

ten months. The pasting and thermal properties and texture, water

uptake and volume expansion ratio and solid loss during cooking

were determined over the storage time. Similar trends were observed

in pasting properties for rice dried using IR, HA and AA. The peak

viscosity and breakdown increased within the first 4 months of

storage and then decreased for dried rice. The peak viscosity of rice

dried with IR was less than those of rice dried with HA and AA.

There was no significant alteration on thermal properties among rice

samples tested. Cooking properties including, volume expansion,

water uptake, solids loss and texture changed in similar fashions for

rice dried using IR, HA and AA. We concluded that the drying using

IR heating under conditions of temperatures of 60 ºC followed by 4 h

tempering and natural cooling has no adverse effect on

physicochemical properties of rice after storage.

19

EFFECTIVE DISINFECTION OF ROUGH RICE USING

COMBINED PULSED ULTRAVIOLET LIGHT AND HOLDING

TREATMENT

B. Wang1,3, R. Khir1,4, Z. Pan1,2, T. H. McHugh2, N.Mahoney2 1Department of Biological and Agricultural Engineering, UCD. 2

Healthy Processed Foods Research Unit, USDA-ARS West Regional

Research Center, 3School of Food and Biological Engineering, Jiangsu

University, 4Department of Agricultural Engineering, Suez Canal

University

There is a great need in developing environmental friendly

technologies for disinfecting rough rice to inhibit the production of

aflatoxins. The objective of this study was to investigate the

effectiveness of disinfection of rough rice against A. flavus using

integrated pulsed ultraviolet light (PUV) and holding treatment.

Samples of freshly harvested medium grain rice (M-206 variety) with

initial moisture content of 23.1±0.1% (w.b.) were used for conducting

this study. The inoculated samples were treated using PUV under

different light intensities ranging from 0.10 to 0.40 W/cm2 and

durations ranging from 10 to 40 s. After PUV treatment, holding

treatment was conducted by keeping the treated samples in an

incubator set at 60 ºC for 2 h followed by natural cooling. The

reductions on population size of A. flavus spores, moisture removal

and milling quality of rough rice were determined. The results

revealed that the PUV treatment under light intensity of 0.12 W/cm2

for 20 s led to temperature of 60 ºC and a reduction of 0.3 log cfu/g on

population size of A. flavus spores. After holding treatment, a 5.0 log

cfu/g reduction was achieved. The corresponding total moisture

removal reached to 4.1% point. There was no adverse effect of

integrated PUV and holding treatment on the milling quality of rough

rice. It has been concluded that simultaneous drying and effective

disinfection of rough rice can be achieved using combined PUV and

holding treatment.

20

THE CONTRIBUTION OF SACRAMENTO VALLEY RICE

SYSTEMS TO METHYLMERCURY IN THE SACRAMENTO

RIVER

C. Tanner, L. Windham-Myers, J. Fleck, K. Tate, S. McCord and B.

Linquist. UCD, United States Geological Survey, and UC Cooperative

Extension.

In anoxic, mercury-contaminated sediments, sulfate- and iron-

reducing bacteria convert inorganic mercury to more bioaccumulative

and toxic methylmercury (MeHg). MeHg biomagnifies in higher

trophic level fish, posing a health risk to fish-consuming humans and

wildlife. In the Sacramento Valley, the conjunction of over 500,000

acres of paddy rice and other anoxic wetlands with mercury-

contaminated soils enhances production of MeHg. This study sought

to quantify the contribution of rice in the Sacramento Valley to MeHg

entering the Delta through a meta-analysis of published MeHg

concentration data from 1996-2007. The analysis focused on sample

sites on agricultural drainage canals, and on the mainstream

Sacramento and Feather Rivers immediately upstream and

downstream of agricultural drainages. All sites showed lower MeHg

concentrations from June through October, and higher, more variable

MeHg concentrations November through May. The period of low

MeHg concentrations roughly corresponds to the rice growing season,

while rice fields are flooded to promote straw decomposition during

the more-variable winter period. Agricultural drainage canals had

higher MeHg concentrations than sites on the Sacramento and

Feather Rivers during both summer and winter seasons. While load

estimation was limited by gaps in flow data and low temporal

sampling density, load estimates supported patterns found in

concentration data, with larger loads from agricultural drainages

occurring during the winter season. These results suggest that rice

may be a source of MeHg to the Sacramento River. However,

comparison to a recent field-scale study in the Yolo Bypass shows

that the contribution of rice to MeHg in the Sacramento River at a

basin scale may be much lower than field scale measurements would

suggest. Future research efforts should seek to reduce the overall

contribution of rice to MeHg in the Sacramento River, particularly

during the seasonal period of higher MeHg concentrations and loads.

21

FIELD TOURS OF RESEARCH

RICE VARIETY DEVELOPMENT

The RES breeding program consists of four research projects. Three

rice breeding projects focus on developing adapted varieties for

specific grain and market types and are each under the direction of a

RES plant breeder. The rice pathology project, under the direction of

the RES plant pathologist, supports the breeding projects through

screening and evaluating varieties for disease resistance, rice disease

research, and quarantine introduction of rice germplasm for variety

improvement. All projects also linked with the DNA marker

laboratory and are involved in cooperative studies with other

scientists from the UC, USDA and industry, including off station field

tests, nurseries, quality research, and biotechnology. Brief highlights

of the RES breeding program are discussed here and will be

presented during the field tour of the breeding nursery.

Medium Grain

(V.C. Andaya, Plant Breeder, RES)

Medium grain varieties developed at the Rice Experiment Station,

commercially known as Calrose, are the predominant type of rice

grown in California. Calrose varieties are estimated to be planted to

more than 90% of rice acreage in the state, three of which, M-206, M-

205, and M-202, are widely grown early maturing Calrose varieties

planted by CA rice farmers. M-206 has superior grain and milling

yields and better cold tolerance while M-205 registers superior grain

yields in the warmer areas of the Sacramento Valley. Acreage of M-

202 is rapidly declining in favor of the better milling and higher

yielding varieties, M-205 and M-206, and some very early varieties.

In 2011, RES released a very early maturing, semi-dwarf, glabrous,

high-yielding Calrose variety, M-105, as an alternative for cooler rice

growing areas where M-104 is commonly grown or where very early

varieties are desired. Its days to heading and yield performance are

in between M-206 and M-104. Resistance to cool temperature-induced

blanking, however, is not better than M-104. This new variety has

22

superior milling yield and stability, better than M-206 milling yields

even when harvested at lower harvest grain moisture. Based on rice

growers’ feedback and reports during the 2013 planting season in

Butte County, M-105 is competitive with the more popular Calrose

varieties and is superior to M-104 in yield and agronomic

performance. It is planted to approximately 14% of BUCRA’s rice

acreage, achieving head rice yield of more than 68%, outperforming

M-205, M-206 and M-104.

At RES, the breeding goals in the Calrose project are focused on the

development of varieties with high and stable grain yield, high

milling yield with excellent grain quality, cold tolerance, and disease

resistance. In the last several years, the project concentrated its

efforts in breeding and pyramiding new sources of blast resistance.

Mutation breeding is also used to find new variants with early

flowering, tolerance to certain herbicides, and improved overall plant

type. Moving forward, the project is taking serious steps to further

improve the grain quality and cooking attributes of Calrose to match

changing international market preference for better tasting rice while

still aiming for highest possible grain yields.

08Y3269, A high-yielding line

The advanced line 08Y3269 is a semi-dwarf, early maturing,

glabrous, and high-yielding Calrose advanced line is in the final

stages of evaluation and will be considered for release in 2015. It was

derived from a cross made in 2004 designated as R29174 with the

pedigree “M-205/3/90Y63/M-202//M-204”. It was first entered in

UCCE Statewide Test (SW) in 2010 and has undergone series of seed

purification in head row nurseries since 2012.

In 2014, a proposal for Foundation Seed increase of 08Y3269 was

submitted and approved by the CCRRF Board of Directors in

accordance with the RES Variety Release Policy and Protocol. If

released, this line may serve as an M-205 or M-202 replacement or

alternative. 08Y3269 is not recommended in areas where M-205 is

not successfully grown such as in cooler rice areas. 08Y3269

performed very well in the statewide yield tests, out-yielding M-202,

M-205, and M-206 by 8%, 6%, and 2%, respectively, using the 4-year

grain yield average. This entry performed best in Butte and Colusa

counties compared to M-205. It heads two days earlier than M-205,

with similar seedling vigor and plant height. In 2013, 08Y3269 was

entered in strip trials in Butte, Glenn, and Colusa where milling

samples were taken and evaluated. Milling yields, in terms of head

23

rice and total milled rice recovered, were similar to M-205 and M-206,

but may slightly drop if harvested at lower moisture levels. 08Y3269

has slightly larger kernels but has less chalky grains compared to M-

205 and M-206. 08Y3269 has better stem rot resistance score but has

no noticeable advantage to the other medium grain varieties in terms

of resistance to rice blast.

Disease Resistance

Stem rot and rice blast diseases are two of the more important rice

diseases in California. In response to the potential breakdown of

resistance in M-208, the medium grain project concentrated efforts in

breeding and pyramiding blast resistance genes that are effective

against the new blast race. In 2005, a backcrossing project was

initiated to introgress different blast resistance genes (Pi genes) into

M-206 background. Breeding lines were selected and advanced using

DNA markers linked to these genes, and the end-result were 10 near-

isogenic lines (NILs) of M-206 containing individual Pi genes. Stable

and uniform NILs were entered in preliminary yield tests to examine

if there are yield penalties and agronomic differences between these

isolines and M-206. Compared to M-206, agronomic performance and

grain characteristics varied depending on the resistance gene

introgressed.

Seven of these near-isogenic lines were entered in statewide test in

2013 and repeated in 2014. In 2013, 12Y113 (containing the Pi-z5

gene) yielded better than M-208 with an average yield of 9,600

lbs/acre. A notice of experimental increase was submitted for 12Y113

and the line is currently being purified in head rows.

Stem rot resistant lines that recovered the medium grain type of M-

206 were isolated from the stem rot resistance mapping project

spearheaded by Dr. Cynthia Andaya and Mr. Jeff Oster. Several of

these lines were entered in small plots for yield and agronomic

performance evaluation. Preliminary evaluation showed that few

stem rot resistant selections are significantly better in terms of

resistance scores compared to the M-206 but they still are later

maturing and low yielding. Resistant lines will be evaluated further

and will be used as parents for further crossing work.

Mutation Breeding

The Calrose project is continuously searching and evaluating traits

that may add value to rice varieties developed for California through

mutation breeding using chemical mutagens (EMS) and ionizing

24

radiation (gamma rays). By generating mutant populations derived

from M-202, M-205, M-206, M401, and other varieties, mutants were

isolated that are short, early maturing, and perhaps with tolerance to

certain herbicides. Generation of mutants and screening protocols are

currently handled by Dr. C. Andaya.

In previous years, early M-401 mutants were isolated from EMS-

treated seeds in the initial chemical mutagenesis experiment in 2010.

The mutants were purified and confirmed through DNA markers to

be true mutants of M-401. All the mutants identified are significantly

earlier maturing than M-401, but showed variation in terms of grain

quality, agronomic performance and eating quality. A high degree of

asynchronous heading that appeared to affect milling yields were

observed. Mutants were cross backed to M-401 for genetic analysis

and were also crossed to other early varieties for allelism testing.

Selected early M-401 mutants are entered in 2014 Statewide yield

test and will be further tested for grain and eating quality. Early

mutants of M-202 were also isolated and being tested in yield plots.

Premium Quality and Short Grain

(S. O. P.B. Samonte, Plant Breeder, RES)

Introduction

The Premium Quality and Short Grains Project encompasses the

improvement of the following rice varietal types:

• Short grain, premium quality (SPQ)

• Medium grain, premium quality (MPQ), and

• Short grain, conventional (SG)

• Short grain, waxy (SWX)

• Short grain, low amylose (SLA)

• Arborio or bold grain (BG)

All new lines are bred and selected for improved and stable grain

yield and yield-related traits, milling and cooking quality, reduced

delay in maturity and blanking due to cold temperature, lodging

resistance, very early to early and uniform maturity, and resistance

to diseases. In addition, there are specific trait parameters that are

selected to qualify a line into a specific grain type. Experimental lines

in nurseries and yield tests are compared against check varieties,

which include S-102 for SG types, Calamylow-201 (CA-201) for SLAs,

25

Calmochi-101 (CM-101) for SWXs, Calhikari-202 (CH-202) and

Koshihikari for SPQs, M-402 and M-401 for MPQs, and 87Y235 for

BGs. Selected lines must show improvements over their respective

checks.

Varieties and Elite Lines

Premium Quality Short Grain: Calhikari-201 and Calhikari-202

Calhikari-202, which was released in 2012, has continued to show its

yield advantage over CH-201 (released in 1999). In the Statewide

(SW) Tests conducted from 2010 to 2013, CH-202 had higher grain

yields than CH-201 in 26 out of 42 test environments, for a 4-year

average of 8,621 lb/acre, which was 4% higher than that of CH-201

(8,278 lb/acre). Based on the 42 test environments, CH-202 was the

higher yielder more frequently in RES, Yolo, and Yuba test locations,

CH-201 was the higher yielder more frequently in San Joaquin and

Colusa test locations, while both varieties were higher yielders on

equal occasions in Sutter, Butte, Glenn, and west Sutter test

locations. Head rice percentage averaged 64% across 2012 and 2013

for both CH-202 and CH-201.

This year, 3 elite SPQ lines are being evaluated in preliminary group

of the SW Tests. Among these, 12Y2167 was noteworthy because of

its higher yield, lower lodging, less blanking, and lower chalkiness

compared to checks CH-201 and CH-202.

Premium Quality Medium Grain: M-401 and M-402

M-401 and M-402, estimated grown in about 6.9 and 0.8% of the rice

acreage in California (http://www.crrf.org/ccrrf_res-v38_026.htm),

respectively, are the standard premium quality medium rice grain

varieties. Based on the SW Tests in 2012 and 2013, their average

grain yields were 8645 and 8238 lb/A, respectively, while head rice

were 59 and 67%, respectively.

This year, there are 8 advanced MPQ lines that are being evaluated

and compared against M-401 and M-402 in the SW Tests. Among the

MPQ lines, 11Y2183 has been outstanding. When averaged across

2012 and 2013, 11Y2183 yielded 9480 lb/acre, which was 15 and 10%

higher than M-402 and M-401, respectively. Compared to M-402 and

M-401, 11Y2183 had higher whole milled rice yield, similar seedling

vigor, earlier heading, less chalkiness, and better taste. MPQ

11Y2183 is undergoing purification and experimental seed increase

this year.

26

Conventional Short Grain Rice: S-102

S-102 is a very early maturing conventional SG variety. In the SW

Tests, its average grain yield (across 2011 to 2013) was 8470 lb/acre.

This year, there are 5 advanced SG lines that are being evaluated in

the SW Tests. SG 09Y2179 showed outstanding performance among

the SG lines. When averaged across 2011 to 2013, 09Y219 yielded

9690 lb/A, which was 14% higher than S-102. Furthermore, when

compared to S-102, 09Y2179 had higher whole milled rice yield,

higher head rice percentage, more days to heading (it is classified as

an early maturing line, unlike the very early maturing S-102), less

lodging, and better resistance to sheath spot. In addition, SG

09Y2179 has a glabrous grain compared to the pubescent S-102. SG

09Y2179 is undergoing seed purification and experimental seed

increase this year.

Waxy Short Grain Rice: Calmochi-101

Calmochi-101 (CM-101), the current standard SWX variety is

estimated to be grown in approximately 3.5% of rice acreage in

California (http://www.crrf.org/ccrrf_res-v38_026.htm). However,

varietal improvements in SWX rice are necessary especially for grain

yield. This year, the SG project is evaluating 4 advanced SWX lines in

the SW Tests, with SWX 09Y2141 being grown in all SW test

locations. SWX 09Y2141 is high yielding, semi-dwarf, early-maturing,

and glabrous. In comparison to the CM-101, 09Y2141 had

significantly higher grain yield in all 27 SW environments that it was

tested in from 2010 to 2013. Test locations were at Butte, Colusa,

RES, San Joaquin, Sutter, Yolo, and Yuba. The yield advantage of

09Y2141 over CM-101 ranged from 17 to 39%. Overall, grain yield

(averaged across 27 environments) was 10,000 lb/acre for 09Y2141

and 7,860 lb/acre for CM-101. Furthermore, when compared to CM-

101, 09Y2141 was similar in seedling vigor, taller by about 3 cm, it

required two more days to reach heading, and lodged 3% more. SWX

09Y2141 had a higher head rice percentage at 65%, larger grain size

dimensions, and lower viscosity when cooked. Blanking, which was

based on the San Joaquin Trials, was slightly higher in 09Y2141 than

CM-101. In 2013, some comments from the external evaluations on

cooking quality indicated that 09Y2141 was softer than CM-101, and

that it may be useful for soft Mochi such as Raw Mochi and Wagashi,

Japanese traditional confectionery. SWX 09Y2141 was purified in

isolated water-seeded headrows in 2013, and it is being grown in the

foundation seed increase field and headrows this year. The SW Tests

have shown that 09Y2141 is superior to CM-101, which was released

in 1985.

27

Low Amylose Short Grain Rice: CA-201

Calamylow-201 (CA-201) is the current SLA variety. However, its low

grain yield and high lodging percentage are unattractive traits that

need improvement. This year, 12 advanced SLA lines are being

evaluated in the Preliminary Yield Tests (PYT) at RES. Selections

that pass the PYT are advanced to the SW Tests.

Arborio or Bold Grain Rice

Arborio or bold grain rice types are grown on a small acreage in

California. RES has not released a BG variety, but it has released

87Y235 as a germplasm in 1994. The development of improved BG

lines is the first step to increase interest in this type of rice.

Currently, three advanced BG lines are being evaluated in the PYT at

RES.

Breeding for Disease Resistance

Reactions to stem rot, aggregate sheath spot, and blast by breeding

lines of the SG project that are entered into the PYT and SW Tests

are evaluated by RES pathologist Jeff Oster. In 2013, medium grain

lines pyramided with blast resistance genes by the Medium Grain

Breeding Project of Dr. Virgilio Andaya were used as parents in

crosses with lines and varieties of the Short Grain Breeding Project.

Marker-assisted selection for blast resistance in the resulting F2 and

F3 plants is being conducted in cooperation with Dr. Cynthia Andaya.

Long Grains

(Farman Jodari, Plant Breeder, RES) The objective of the long grain project is to develop superior

conventional long-grain and specialty long-grain varieties for

California. Main emphasis in the conventional (southern) long-grain

breeding category includes superior cooking quality, yield potential,

milling yield, milling yield stability, cold tolerance, seedling vigor,

and disease resistance.

L-206

This very early to early maturing semi-dwarf, conventional long-grain

variety was released in 2006. L-206 has shown improved cooked grain

texture and higher grain yield over earlier varieties. Average

heading date in 2014 statewide test at RES was 1 day earlier than

28

M206. Plant height is 11 cm shorter than M-206. L-206 has slightly

stronger amylographic profile, as shown by higher cool paste viscosity

and RVA setback values. Consequently cooked grain texture of it is

less sticky than L-204. Similar to Southern long grain, L-206 has

intermediate amylose and gelatinization temperature types.

L-206 is adapted to most rice growing areas in California except the

coldest locations of Yolo and San Joaquin counties. Average grain

yields of L-206 during 2006 to 2013 early statewide trials (RES,

Butte, Colusa, Yuba), was 9510 lb/A, as compared to 9380 for M-206.

Average head rice yield of L-206, however, is 62 %, which is 3% lower

than M-206. Fissuring studies indicate that L-206 is significantly

more resistant to grain fissuring than L-204, indicating a better

milling yield stability at lower grain moisture contents.

Results of a comprehensive study in 2012 sponsored by USA Rice

federation and conducted by Southern US experiment stations and

commercial milling companies have indicated that L-206 is highly

favored for packaging quality. Results indicated that L-206 was

ranked 1st among all US long grain varieties and hybrids for package

quality by the participating rice mills. The evaluation criteria that

were used included bran streaks, chalk, kernel color, uniform length,

and overall appearance. Concerted effort continues in the long grain

project to maintain and further improve the marketability qualities of

advancing long grain breeding material.

Among promising experimental long grain lines that are being tested

in 2014, entry 11Y1005 have shown excellent agronomic and quality

traits. Detailed performance of this line is included in RES annual

reports (http://www.crrf.org). In 2012 and 2013 very early statewide

tests average yield of 11Y1005 was 475 lb/A higher than L-206.

During the same period, 11Y1005 showed 2% higher head rice yield.

Cooking quality and grain appearance of these lines are similar to L-

206. Purification of 11Y1005 is currently underway. Currently this

line is being tested in all 8 of the statewide test locations.

The genetic base of long grain breeding material at RES has been

significantly expanded in recent years through the use of germplasm

from Southern US and world collection sources. This diversity is

being used to incorporate the desirable agronomic and quality traits

in the elite RES lines.

29

Specialty Long Grain

Breeding efforts continue in an accelerated pace, as market demand

for these types continues to increase. Currently, efforts are underway

to develop soft cooking aromatic jasmine, elongating aromatic

basmati, and conventional long-grain aromatic types adapted to

California. Specialty long grains currently occupy nearly half of the

long grain breeding nursery.

Calmati-202

This early maturing basmati type variety was released in 2006.

Quality improvements in this variety include more slender kernels,

higher cooked kernel elongation ratio, and more flaky grain texture.

Similar to Calmati-201 (CT-201) this variety is adapted to warm

growing areas. Grain yield of Calmati-202 (CT-202) has averaged

6740 lb/acre, which is 74% of M-202 yield potentials. Head rice yield

recovery of this variety is considerably lower than standard varieties

due to its slender grain shape, averaging 58%. It has a semi-dwarf

pubescent plant type with good seedling vigor. Maturity is similar to

CT-201 at 93 days to 50% heading. Milled kernels of this variety are

longer and narrower than CT-201 but not as slender as imported

basmati. Grain fissuring studies have shown that CT-202 is

susceptible to fissuring at low harvest moistures. Timely harvest and

proper handling is recommended to preserve milling as well as

cooking qualities of this variety. Due to slender grain shape and

pubescent hull and leaf, drying rate of the grain at harvest is

significantly faster than standard varieties. Recommended harvest

moisture is 18 to 20 percent.

A new series of basmati lines have been developed, including 5

entries that are currently being tested in 2014 statewide trials. These

lines have shown cooking qualities that are nearly indistinguishable

from imported basmati types. Grain and milling yields of these lines,

however, seem to be similar to or lower than CT-202. Current

breeding efforts are directed toward increasing both grain yield and

milling yield while maintaining their basmati quality traits. Their

adaptability thus far is limited to warmer rice growing region.

Efforts have significantly increased in jasmine type breeding and

currently occupy the largest section of the specialty nursery.

Conventional pedigree and mutation breeding methods are being

used. Jasmine type germplasm lines from southern breeding

programs and foreign introductions including the original Thai

Jasmine variety, ‘Khao-Dawk-Mali 105’, are being utilized. In 2014

30

statewide tests, 8 jasmine type selections are being tested. One entry,

11Y106, is currently being produced as headrow. It has shown good

cooking qualities with soft cooking texture and strong aroma.

Samples will be presented to marketing organizations in 2014 for

inputs regarding it market acceptability.

Quality testing was further expanded in 2013 for all advanced long

grain selections including conventional as well as specialty types.

Screening for amylographic profile through RVA was nearly doubled.

This is in an effort to match the cooking quality of conventional,

jasmine and basmati types to those of the current market.

Aromatic Experimental 11Y1049

This conventional cooking type aromatic line was released in January

2014, as variety ‘A-202’. This variety is intended to be a replacement

for the aromatic variety A-301. A-202 is early maturing, semi-dwarf,

and glabrous. Compared to A-301, A-202 is 9 days earlier, 4” taller,

and has significantly higher seedling vigor score. Average yields, in

lb/A in 2012 and 2013 ‘early’ statewide tests was 9100 and 7300 for A-

202 and A-301, respectively. Average headrice yields during the same

period were 60% and 53% for A-202 and A-301, respectively. Milled

kernels of A-301 are slightly bolder than A-301. The recommended

ratio of water to rice for cooking of A-202 is 2 to 1. Amylose content,

gelatinization temperature type and amylographic profile are similar

to A-301. Aroma volatilization of A-202 is slightly less during cooking

process. Flavor sensory of this variety, however, is similar to A-301.

Preliminary tests conducted in 2012 have also shown that under

organic production system A-202 has considerable yield advantage

over A-301 variety. A-202 is susceptible to cold induced blanking and

not recommended for production in cold locations. Areas of adaptation

for A-202 include Butte, Yuba, Colusa, Glenn, and Sutter Counties.

Stem Rot

Resistance breeding efforts continues in cooperation with RES plant

pathologist. The Oryza rufipogon source of resistance has been

incorporated to various long grain backgrounds. Majority of these

lines are early maturing and possess good level of cold tolerance.

Stem rot resistant experimental lines such as 10Y1008 continue to

produce consistently very high grain yields within the long grain

nursery. Milling quality improvement of these lines is currently the

primary breeding objective.

31

Rice Pathology

(J.J. Oster, RES)

The primary focus of the project is to facilitate the development of

improved disease resistance for the breeding projects by developing

and applying screening techniques to measure and score breeding

lines for selection, advancement, and data on breeding lines. This is

done by producing inoculum in the lab and managing disease

nurseries for optimal disease development. All advanced entries (646

entries, 2041 rows this year) in yield trials are evaluated for

susceptibility to stem rot in the field and aggregate sheath spot in the

greenhouse. Several years of testing are required to accurately

characterize the level of resistance in these entries.

The pathology project handles rice germplasm requests by the

breeders which must go through quarantine. All seed imported from

other countries is treated according to a permit issued by the USDA

and subject to inspections by CDFA to prevent introduction of new

pathogens/pests into California. Materials are then released for use

in the breeding program. This quarantine procedure ensures that the

breeders have access to traits important to the continuing

improvement of California varieties. In 2010, seven entries with cold

tolerance were introduced through quarantine.

M-208, was released in 2005, and gets its resistance from the major

gene, Pi-z. Major genes for disease resistance largely prevent

development of disease lesions on resistant rice. M-208 is resistant to

the IG-1 race found in California when the blast disease was first

found in California in 1996-7. In 2010, blast lesions were found on M-

208. Incidence was low (about 1 in 10000 plants was infected). The

blast fungus was isolated from these lesions. Inoculation tests on

differential varieties (varieties with different resistance genes) show

that not all the isolates are the same pathogenically, and that new

race(s) (pathotypes) now exist in California. One of these races can

defeat Pi-z and Pi-km/Pi-kh genes, even though Pi-k is not present in

any RES varieties. This race is similar to IB1. DNA tests at UC

Riverside on a different set of isolates taken from M-208 as well as

the original IG-1 isolates show that all the isolates have similar DNA

banding patterns (the isolates belong to the same lineage).

Worldwide, lineages often contain several pathotypes. So far, the IB1

race has not increased in frequency. It remains to be seen whether

these new races will spread and become more common. Additional

32

tests with IG-1 race isolates showed that M-208 is still resistant to

these isolates.

A backcrossing program started in 2005 has been completed after

seven backcrosses from donors with 10 different resistance genes into

M-206. These lines are very similar to M-206, but with a blast

resistance gene. The breeders have observed these lines in the field

and brown rice in the lab, and are being used in crossing. Many of

them yield more than M-208 and as much as M-206. They have also

been screened against sheath spot and stem rot, but are susceptible

to these diseases.

A similar backcross program was started in 2005 to transfer stem rot

resistance derived from Oryza rufipogon 100912 and O. nivara

105316 into M-206. Both long and short grain high yielding resistant

lines were used as donors in this transfer. Advanced generation

materials from each backcross level are screened in the field, where

the breeders can view resistant materials. Stem rot resistant

advanced generation materials were cross-screened against aggregate

sheath spot in the greenhouse. The result is lines with resistance to

both diseases. This material has been turned over to the breeding

projects. Currently, environmental effects and the need for multiple

years of testing greatly slow selection for disease resistance. A few

lines yielded as much as M-206 in 2013. Therefore, mapping

populations have been developed for both sources of resistance. Drs.

Virgilio and Cynthia Andaya are analyzing these populations to

develop markers for use in selecting for stem rot resistance. This

technology could allow for selection of resistant materials in early

generations and allow faster identification of resistant materials.

Finally, sheath blight resistance was found by southern researchers

in Jasmine 85, Te Qing, and MCR10277. Sheath blight is similar to

the aggregate sheath spot disease we have in California. There are

reports of dominant, single gene resistance in Jasmine and Teqing,

with the resistance gene being different in each variety. QTL studies,

however, indicate some genes in common, and some genes differing

between resistance sources. MCR10277 resistance is reportedly due

to 2 recessive genes. These three varieties are also resistant to sheath

spot. Unfortunately, Jasmine 85 and Te Qing are of the indica race,

which does not breed well with the japonica race grown in California.

A backcross program similar to that being followed for SR was started

in 2005 and is has been used to transfer this resistance into M-206

and L-206. Advanced generations from each backcross level have also

33

been screened against stem rot. A few lines have resistance to both

diseases. This material is now being turned over to the breeding

projects.

Preliminary data from Louisiana researchers found a major

resistance factor to sheath blight and that it is also present in the

stem rot and sheath spot resistant materials. Markers are available

to detect this factor. Eventually, molecular markers may be used to

detect resistance to all three diseases, greatly facilitating production

of the resistant varieties of the future.

Virgilio “Butz” Andaya is Director of Plant Breeding & Medium-Grain

Project Leader, Farman Jodari Long-Grain Project Leader, Stanley O.

P.B. Samonte is Premium Quality & Short-Grain Project Leader, Jeff

Oster is Rice Pathologist, and Cynthia Andaya, is Research Scientist

(DNA Lab) at RES.

34

Fifteen Years of Pyrethroid Insecticide Use in Rice

– Are These Products Still Effective? Are There

Viable Options Nearing Registration? What Is the

Future of IPM of Rice Invertebrate Pests?

(L. D. Godfrey, K. Goding, and M. Aghaee, and L.

Espino, UCCE and UCD)

Pyrethroid insecticides were registered for use in rice in California in

1999 with lambda-cyhalothrin being the initial product to market

quickly followed by (S)-Cypermethrin. These products, along with

Dimilin (diflubenzuron), replaced carbofuran that was phased out of

the market due primarily to non-target concerns. Over the last 15

years of use, pyrethroids now get about 99% of the insecticide use in

California rice.

The switch to pyrethroids in rice required a new management

approach compared with the use of carbofuran. Following a brief

learning curve in the late 1990’s to early 2000’s, the industry learned

how to best use these products and the cost:benefit ratio of these

applications has been excellent. Carbofuran primarily targeted the

larval stage of the rice water weevil whereas the pyrethroids provided

control by killing the adults thereby preventing oviposition and the

occurrence of the larval stage. Missing the window of application for

the pyrethroids resulted in very poor control so appropriate timing

was critical.

After 15 years of use in rice are the pyrethroids still effective, viable

products? Insecticides can be lost from the marketplace due to

regulatory and biological aspects. Pyrethroid insecticides are very

toxic to non-target organisms. However, the industry has been very

careful and diligent to prevent off-site application/movement of these

products and the concerns in this regard have been mitigated. The

California Department of Pesticide Regulation (DPR) started a

reevaluation of certain pesticide products containing one or more

pyrethroid active ingredients on August 31, 2006. This was primarily

done because monitoring surveys and toxicity studies revealed the

widespread presence of synthetic pyrethroid residues in the sediment

of California waterways at levels toxic to certain indicator aquatic

species. Additional data were required to address this topic/concern.

During the process of this evaluation, it was determined that there

was limited data on urban offsite movement compared to agricultural

35

use patterns. In July 2012, DPR put into place regulations designed

to reduce runoff from outdoor residential use of pyrethroids and this

reevaluation concluded in May 2014. DPR will continue to monitor

and address agricultural and indoor use patterns of pyrethroids, if

needed.

Insecticide resistance is a biological process that can compromise the

usefulness of insecticides. The dependence on the pyrethroid class of

chemistry in the rice system is one factor which could promote the

build-up of resistance. Reports from PCAs the last few years have

suggested the efficacy of the pyrethroid products may not be to the

level seen in previous years. In 1999, the susceptibility of rice water

weevil to lambda-cyhalothrin was determined via a laboratory

bioassay method. This was before this active ingredient had been

used to any extent for rice water weevil control. This same

evaluation was done in 2013 from weevils collected in Butte Co. and

these weevils were equally susceptible to lambda-cyhalothrin as in

1999. Therefore, there was no evidence of the build-up of resistance.

Although based on regulatory and biological aspects, pyrethroid

products are still viable and useful products, it is unwise to

completely rely on one class of chemistry for managing invertebrate

pests in rice. Resistance can “appear” quickly and regulations can be

imposed based on “new science” or public pressure quickly changing

the availability of products. Staying current and adopting the newest

and most advanced management tactics also has merit along with, as

much as possible, keeping up-to-date with the other rice producing

states.

Belay® (clothianidin) was registered for use in the 2014 rice season in

California. For rice water weevil control, research has shown that

this product is best applied at the 2 to 3 leaf stage. Control is from a

combination of effects on the adults as well as direct kill of the

damaging larval stage. There is also activity with a preflood as well

as a rescue (5 to 6 leaf stage application) but this control is not to the

level of the 2 to 3 leaf stage timing. As this product is used under

grower conditions, conditions, such as rate, timing, etc., needed to

optimize the cost-effectiveness can be fully determined. Our studies

have shown that this insecticide has minimal effects on other aquatic

non-target organisms. These are important components of aquatic

ecosystems as well as part of food webs that feed upon mosquito

larvae. Clothianidin is a neonicotinoid insecticide; this class of

insecticide has been suggested to be involved in the problems

impacting honey bee populations in recent years. However, use of

36

this active ingredient at the 3 leaf or earlier rice stage should

minimize exposure to bees as this is long before any floral attractants

are available for bees. Discussions with local apiculturists have

supported these ideas.

Coragen® (rynaxypyr) is another insecticide under development for

rice water weevil management. Our research has shown this

insecticide provides optimal rice water weevil management with a

preflood application. In the southern rice system, rynaxapyr is used

as a seed treatment and is highly effective against several insect

pests. However, in our water-seeded system, the seed treatment

application method has not been consistently effective. In contrast,

the preflood application of rynaxapyr is very effective.

Cruiser® (Thiamethoxam) is being evaluated extensively in ring plots

in 2014 as a seed treatment. This active ingredient is registered on

rice (including California) on dry-seeded rice. The performance

against rice water weevil on our more typical water-seeded rice is

being determined.

An environmentally friendly alternative biopesticide against rice

water weevil larvae has also been studied. This is based on the

bacterium Bacillus thuringienesis spp. galleriae (Btg). The Btg

granular formulation (Phy-4-12) performed as well as lambda-

cyhalothrin in greenhouse and field trials. Foliar formulations of Btg

applied after flooding were less effective.

With the upswing in tadpole shrimp populations in recent years and

the loss of the usefulness of copper sulfate in many areas, new

insecticides are needed for this pest. The products mentioned above

for rice water weevil, pyrethroids, Belay, and Coragen have activity

on tadpole shrimp but I would classify them as only moderately

effective. More active materials are needed.

Larry Godfrey is a UC Cooperative Extension Specialist and

Entomologist in the Agricultural Experiment Station, Department of

Entomology and Nematology, UCD; Kevin Goding is a Staff Research

Associate, Department of Entomology and Nematology, UCD;

Mohammad-Amir Aghaee is a Graduate Student Researcher,

Department of Entomology and Nematology, UCD, and Luis Espino is

a Rice Farm Advisor, Colusa Co, UCCE.

37

Rice Weed Control: Herbicide Programs, New

Chemicals, and Weed Management

(A.J. Fischer, W. Brim-DeForest, R. Alarcon-

Reverte, R. Pedroso, B.A. Linquist, C. Greer, L.

Espino, R.G. Mutters, Farm Advisor, Butte Co, J.E.

Hill, S. Johnson, and J.R. Stogsdill, SRA II, UCD

and UCCE)

Our field program includes the testing of herbicides, their mixtures

and sequential combinations for the rice growing systems that

currently prevail in California. At this years’ field day we will show

highlights of our weed control experiments conducted on the Rice

Experiment Station’s (RES) Hamilton Road field. Experiments in

2014 involved water seeded continuously flooded rice, early-drain

(pinpoint) systems, and drill seeded systems. In addition, our

research effort also includes areas in two cooperating grower’s fields

infested with multiple-herbicide resistant late watergrass (“mimic”)

and ALS-resistant sedges. We continue to test new products and to

assist the rice industry in the registration of new herbicides as

options become available. We have a strong emphasis towards the

diversification and sustainability of weed management in rice, thus

we continued work on the evaluation of different irrigation methods

and their impact on weed communities, as well as the development of

growth and emergence models, which will eventually be utilized to

create prediction tools for farmers to improve the timing of herbicide

applications. Our efforts seek to assist California rice growers in

their critical weed control issues of preventing and managing

herbicide-resistant weeds, achieving economic and timely broad-

spectrum control and complying with personal and environmental

safety requirements.

Here we highlight results from our 2014 field operation for the major

rice growing systems used in California. Efficacy comments mostly

reflect herbicide program performance by approximately 40 days after

seeding (DAS) rice, thus covering the critical period for weed control

in water-seeded rice determined at the RES.

Continuously flooded rice

This system intends to maximize weed suppression by flooding,

notably the elimination of barnyardgrass and sprangletop as

problems. After seeding into a flooded field, water depth is

38

maintained at 4 inches throughout the season. When late post-

emergence applications are needed, water is lowered to expose about

70% of weed foliage to the herbicide spray, but fields are never

drained. Watergrass (early and late) were the predominant weeds,

followed by ricefield bulrush, smallflower and ducksalad. All weeds at

our field site are susceptible, but we discuss and give herbicide

options for fields with both resistant and susceptible populations.

For control of multiple-resistant watergrass in locations with

susceptible sedge and broadleaf populations, an application of a tank

mixture of Abolish + Regiment (1.5qt/a + 0.53oz/a + 2.0% v/v UAN +

0.2% v/v NIS) at the 5 lsr (leaf stage of rice) provides good control.

Options for early sedge and susceptible grass control include Granite

GR alone (15lb/a) at the 2-3 lsr, or Cerano (day of seeding at12lb/a)

followed by Granite GR (15lb/a) or Butte (7.5lb/a at 1 lsr) at the 2-3

lsr. All three options provide excellent control of ricefield bulrush,

smallflower and ducksalad. The combination of Cerano followed by

Granite provided the best watergrass (susceptible) control (100%).

Butte is a good option for sites with ALS or propanil resistant sedge

populations.

Bolero is a granular into-the-water herbicide that can be used to

begin an herbicide program in which it helps with sprangletop

(although this weed should be uncommon in continuously flooded

rice) and with ALS-inhibitor and/ or propanil-resistant smallflower

umbrellasedge control. A program with Bolero applied at 23 lb/a at 1

lsr followed by Regiment (0.8oz/a at 3-4 lsr) provided good watergrass

and ricefield bulrush control (93%) and excellent smallflower

umbrellasedge control (100%). Regiment at the highest label rate is

an option for fields with multiple-resistant watergrass. In susceptible

watergrass fields, a good alternative is also to follow Bolero with

Granite SC + SuperWham (2oz/a + 6 qt/a + 1/25% v/v COC) at the 3-4

lsr. Watergrass control was good (92%), while ricefield bulrush,

smallflower umbrella sedge and ducksalad control were excellent

(100%). When Bolero was followed by SuperWham alone (6 qt/a +

1/25% v/v COC) at the 3-4 lsr, control of ricefield bulrush was also

good (96%), as was control of ducksalad (92%).

An alternative granular formulation to control susceptible sedges and

watergrass is Granite GR (15lb/a) at the 1 lsr followed by

SuperWham (6 qt/a + 1/25% v/v COC) at the 3-4 lsr. It provided 100%

control of sedges and ducksalad, and good grass control (97%).

39

Shark H2O is a good herbicide for a program aimed at controlling

ALS inhibitor- and/or propanil-resistant sedges (thus delaying the

evolution of resistance to those herbicides. Shark H2O alone into the

water (7.5oz/a) at the 1 lsr had good early control of bulrush (86%) but

late-emerging bulrush was not well controlled. Smallflower control

was good and lasted until 40 days after seeding (86%). Abolish +

Regiment (1.5qt/a + 0.53oz/a + 2.0% v/v UAN + 0.2% v/v NIS) at the 5

lsr provided 91% control of watergrass (this mixture is also good for

the control of multiple-resistant watergrass). Regiment at the 5 lsr

will also suppress resistant watergrass. When Cerano was applied

day of seeding (DOS) (12lb/a) followed by Shark H2O and then by an

Abolish+Regiment mixture, control of watergrass increased to 96%.

When Granite GR (15lb/a) and Shark H2O (7.5oz/a) were applied

together at the 2.5 lsr, control of all weeds was excellent (100%).

To increase control of ricefield bulrush for sites with heavy

populations, another option is to combine Shark H2O + Halomax

(7.5oz/a + 1.33oz/a) for in into the water treatment at the 2-4 lsr.

Control of both ricefield bulrush and smallflower was excellent

(100%) and the control of watergrass by Cerano (12lb/at DOS) was

enhanced by this mixture. Any escapes can be controlled with a

follow-up application of SuperWham at the 1-2 tiller stage (6qt/a +

1.25% v/v) (98% watergrass control).

Bolero and Cerano are two good options for early grass (watergrass

and sprangletop) control in a Shark H2O-based program in a

continuous flood. Bolero (23lb/a) applied at the 1 lsr had good

watergrass control (95%), as well as good ricefield bulrush and

smallflower control (80% and 96%, respectively). When Bolero was

followed by Shark H2O + Halomax (7.5oz/a + 1.33oz/a) at the 2-3 lsr,

control of sedges increased to 98%. Cerano (10lb/a) at DOS alone

controlled 92% of watergrass; when followed by Shark H2O +

Halomax (7.5oz/a + 1.33oz/a) at the 2-3 lsr, watergrass control

increased to 99%. Sedge and broadleaf control was excellent (100%).

Stand reduction was a problem in the Bolero-based treatments.

Early drained water-seeded rice

Often, cold weather or windy conditions in spring require early field

drainage to favor rice establishment. Also, fields are often drained

for use of foliar-acting early post-emergence herbicides.

40

Pinpoint flood

In this experiment weeds were controlled by foliar herbicide

treatments applied during a period of field drainage for good weed

exposure to the herbicides. Prevailing weeds were early and late

watergrass, ricefield bulrush, sprangletop and ducksalad.

A tank mix of Clincher + Granite SC (13oz/a + 2oz/a + 2.5% v/v COC)

at the 3-4 lsr provided good control of sedges and excellent control of

sprangletop (100%). For sites with multiple-resistant watergrass, a

follow-up of Abolish + Regiment (1.5qt/a + 0.53oz/a + 2.0% v/v UAN +

0.2% v/v NIS) or Regiment (0.8oz/a + 2% v/v UAN + 0.2% v/v) at the 1

tiller stage of rice provides control of watergrass escapes. A 3-way

tank mix of Clincher + Granite SC + Abolish (13oz/a + 2oz/a + 1.5qt/a

+ 2.5% v/v) showed comparatively reduced efficacy on the sedges (89%

control of ricefield bulrush and 95% control of smallflower), and

sprangletop (81%).

For sites with susceptible sedge and grass populations, there are

several good programs. Regiment (0.67oz/a + 2% v/v UAN + 0.2% v/v

NIS) at the 3-4 lsr followed by SuperWham + Clincher (6qt/a + 13oz/a

+ 2.5% v/v COC) at the 1 tiller stage of rice provided excellent broad-

spectrum control. Clincher (13oz/a + 2.5% v/v COC) at the 3-4 lsr

followed by SuperWham + Grandstand (6qt/a + 8oz/a + 1.25% v/v

COC) provided excellent watergrass and sprangletop control (96%

and 100%, respectively) and good ricefield bulrush and smallflower

control (94% and 80%, respectively). Granite SC (2oz/a + 1.25% v/v

COC) followed by SuperWham + Clincher (6qt/a + 13oz/a + 2.5% v/v

COC) controlled watergrass (99%) and sprangletop (100%). Efficacy

on sedge and broadleaves was excellent (greater than 97%). As in

previous years, a tank mixture of Clincher and SuperWham (13oz/a +

6 qt 2.5% v/v COC) at the 3-4 lsr provided good broad-spectrum

control of all weeds except for broadleaves, but the antagonism

between the two herbicides lowered their efficacy slightly (control of

sprangletop was only 75%).

Drill seeded rice

This is the system that offers flexibility for herbicide use when

proximity to sensitive crops imposes restrictions to aerial

applications. Drill seeding favors weeds adapted to dryland seedbeds

(sprangletop is typically problematic, as are barnyardgrass and

smallflower umbrella sedge) and is less favorable for aquatic species

(ricefield bulrush, ducksalad, and redstem). Thus dry seeding is

useful for alternation with water-seeded systems when the pressure

41

of aquatic weeds becomes problematic. Main weeds in the experiment

were the Echinochloa complex, sprangletop, and some smallflower

umbrella sedge. Before heading, the Echinochloa complex is difficult

to differentiate. Later weed ratings will determine the percentage of

one species versus another.

For early weed control, some herbicides are applied before rice

emergence. For a delayed pre-emergence application, the field is first

drill seeded into dry soil. The field is flushed once, to moisten the soil

and imbibe the rice seed, and then a liquid herbicide is applied onto a

moist soil surface. Prowl (2 pt/a) is a pre-emergence herbicide that

can protect from weed emergence after seeding rice during the period

prior to the permanent flood. Abolish is another option as a pre-

emergence herbicide. Both herbicides should be active against

watergrass, barnyardgrass, and sprangletop; Abolish is more active

on smallflower umbrellasedge than Prowl. Prowl H2O (2pt/a) applied

alone at delayed pre-emergence (DPRE) provided only partial (34%)

Echinochloa suppression, 75% control of sprangletop and 85%

smallflower umbrellasedge control, indicating it is not a stand-alone

herbicide but that it can be a useful mixing partner to limit weed

emergence from soils (does not have foliar activity). Abolish (1.5 qt/a)

provided poor late watergrass control (only 5%) but better early

watergrass/barnyardgrass control (up to 76%) and controlled

sprangletop by 70%. Abolish alone in DPRE control smallflower

umbrellasedge by 93%. A follow-up application of a tank mixture of

Abolish and Regiment (1.5qt/a + 0.53oz/a + 2.0% v/v UAN + 0.2% v/v

NIS) provided excellent watergrass grass control (up to 95% of late

watergrass).

The tank mixture of Prowl H2O (2pt/a), SuperWham (4qt/a) and

Clincher (13oz/a) applied with 2.5% COC at the 2-3 lsr is a standard

mixture that controlled emerged grasses (94% control of late

watergrass, 61% control of sprangletop by 40 days after seeding rice,

DAS) and smallflower umbrella sedge (85% control by 20 DAS) while

Prowl suppressed the emergence of germinating weeds. The tank

mixture of Prowl H2O (2pt/a), Granite SC (2oz/a) and Clincher

(15oz/a) applied with 2.5% COC at the 2-3 lsr was another good

option, providing overall best grass control (99% watergrass control,

82% sprangletop control) although control of smallflower was poor

(47%) and would have required a follow-up application.

42

New Compounds

Wetcit® (crop oil based surfactant) By Oro-Agri

Under a continuous flood, SuperWham (6 qt/a) + Wetcit® (1.25% v/v)

applied at the 1-2 tiller stage of rice controlled watergrass (71%),

ricefield bulrush (93%), smallflower (100%) and ducksalad (74%).

When applied with a generic crop oil concentrate, at the same timing

and rate, control of watergrass, ricefield bulrush and ducksalad were

slightly lower (66%, 90%, and 58%, respectively).

RiceEdge® (dry flowable mixture of propanil and halosulfuron) by

RiceCo, LLC

RiceEdge® was tested under a continuous flood and a pinpoint flood

(drained for one week at the 3-4 lsr). In both trials, it was applied at

the highest label rate, of 10 lb/a (+ 1.25% v/v COC) at the 1-2 tiller

stage of rice. In the continuous flood, it controlled watergrass (68%),

and had excellent control of both ricefield bulrush and smallflower

(99% and 100%). In the pinpoint, the same rate and timing controlled

60% of watergrass, and had excellent control of ricefield bulrush and

smallflower (95% and 100%). Phytotoxicity was low (5% tip burn).

The mixture did not perform well when applied at a later timing (40

DAS).

League MVP® (granular mixture of thiobencarb and imazosulfuron)

By Valent

This year, we tested a new League MVP® formulation with a higher

concentration of both thiobencarb and imazosulfuron (11.67% +1%) in

comparison to the current commercial formulation (10% +0.43%).

Under a continuous flood, League MVP® (30lb/a) of the currently

commercial formulation applied into the water at the 1 leaf stage of

rice (lsr) fully controlled ricefield bulrush, smallflower and ducksalad.

Control of watergrass was excellent, at 98%. Applied at 30lb/a at the

2 lsr, the current commercial formulation continued to give excellent

broad-spectrum control, although phytotoxicity was higher than at

the 1 lsr (some stand reduction). The new formulation with 11.67%

thiobencarb +1% imazosulfuron, applied at the same rate (30lb/a) had

excellent control of the same weed species at both the 1 lsr and 2 lsr.

Higher stand reduction was observed with the higher percentage of

thiobencarb. For fields with multiple-herbicide-resistant watergrass,

a follow-up application of Regiment (0.8 oz/a) at the 1-2 tiller stage of

rice will improve control. At a later timing (3 lsr), both formulations

provided excellent control of watergrass (over 97%), ricefield bulrush

and smallflower (100%), though ducksalad control was lower than at

43

the earlier timings (58% in comparison to over 90%). Phytotoxicity

was low at the later application timing (3 lsr).

Butte® (granular mixture of benzobicyclon and halosulfuron) By

Gowan

Butte® was tested under a continuous flood, both alone and in a

program. Phytotoxicity on rice was very low. The granular

formulation of Butte (7.5lb/a) applied at the 1 lsr had good watergrass

control (97%) early in the season and excellent ricefield bulrush,

smallflower and ducksalad control. By 40 days after seeding,

watergrass control was 88%. Follow-up treatments applied at the 1

tiller stage helped maintain the early high level of watergrass control.

Thus SuperWham + Grandstand (6qt/a + 8oz/a+ 1.25% v/v COC),

Regiment (0.67oz/a + 2.0% v/v UAN + 0.2% v/v NIS), or Granite SC

(2oz/a + 1.25% v/v COC) provided 100% watergrass control. Redstem

control was best when Grandstand was used. Rice bleaching was high

and some stand reduction observed, but broad-spectrum weed control

was best with the sequence of Cerano (12lb/a) followed by Butte (7.5

lb/a) at 1lsr.

Weed Management

The evolution of herbicide resistance in major weed species of

California rice, including Cyperus difformis L. (smallflower

umbrellasedge) and Echinochloa phyllopogon (Stapf) Koss (late

watergrass), has necessitated the search for alternative management

options, including alternate herbicide modes of action and tillage

practices in conjunction with the use of a stale seedbed. In addition to

the prevailing water seeding and continuous flooding in rice, reduced

irrigation schemes are being explored for water conservation, which is

expected to alter the usual weed recruitment patterns.

Weed Germination, Emergence and Growth Models

To establish appropriate timing of weed control interventions under

variable field conditions, it is necessary to be able to predict the

dynamics of weed germination and emergence under those conditions.

Laboratory-generated models of germination and emergence for C.

difformis and E. phyllopogon have accurately predicted timing of

germination and emergence in controlled environments by

incorporating information about water potential and temperature

into population based threshold models (PBTM). The models use

hydro- and thermal- time (accrual above a base temperature and base

water potential) to predict population-level germination and

emergence events. Since the ultimate use of these models is to

44

facilitate better management decisions in the field, we are evaluating

them under field conditions. In 2013, observed values in the flooded

systems varied considerably from predicted (laboratory-generated)

values, particularly when comparing initiation of emergence and 90%

emergence. Predicted values of 90% emergence for C. difformis under

flushed conditions were 138 Growing Degree Days (GDD in °C d),

whereas under field conditions, the value was 145 GDD. 90%

emergence of E. phyllopogon under flushed conditions was predicted

to be 227 GDD, and the actual value was 323 GDD. Differences could

be due to a number of factors, including overwintering conditions in

the field, which may affect seed dormancy status differently than the

stratification conditions (wet-chilling) on which the laboratory models

were based. Fields were not flooded over the winter, which may have

resulted in the seeds not being fully imbibed at the onset of irrigation,

causing an increase in GDD in the field in comparison to laboratory

models. The observed differences in the flooded fields could also be

explained by slow emergence due to seedling growth inhibition under

anoxia. Our validation work continued in 2014.

Weed Population Dynamics in Alternative Irrigation Systems

Due to looming water resource issues in California, we have also been

evaluating the dynamics of weed emergence in alternative irrigation

systems. Since 2013, we have been evaluating three systems: i)

Water-Seeded Alternate Wet and Dry (WS-AWD): Flooded for initial

seeding by air, and until canopy closure of the rice, subsequently

allowed to drain and then flushed again when Volumetric Water

Content (VWC) reached 35%; ii) Drill-Seeded Alternate Wet And Dry

(DS-AWD): Drill-seeded, then flushed again when VWC reached 35%;

and iii) Water-Seeded Conventional (WS-Control): permanent flood of

10-15 cm, which was maintained until the field was drained

approximately one month prior to harvest. We will continue to

evaluate the system for at least 2 more years. Preliminary results

confirm earlier results from other dry- versus wet-seeded systems.

The dry-seeded system was dominated by grasses (particularly

barnyardgrass and sprangletop) with a small population of

smallflower umbrella sedge. The wet-seeded systems were dominated

by aquatic weeds: primarily ducksalad, ricefield bulrush, and some

watergrass. With full-control of weeds, yields were the same across

all systems (10 t/ha). Without weed control, yields in the dry-seeded

system were 0 t/ha. In the two water-seeded systems. yields were not

significantly different from each other; the WS-AWD yielded slightly

lower (5 t/ha) than the WS-Control (7 t/ha).

45

Herbicide Resistance in Smallflower Umbrella Sedge

Smallflower umbrella sedge (Cyperus difformis L.; CYPDI) is a

troublesome annual weed (Cyperaceae) commonly found in rice fields

worldwide. In CA, CYPDI management was complicated by the

evolution of resistance to acetolactate-synthase (ALS)-inhibiting

herbicides in 1993; ALS-resistant (R) CYPDI populations are now

widespread throughout CA rice fields. In the wake of resistance to

ALS inhibitors, the post emergent photosystem II (PSII)-inhibiting

herbicide propanil (3,4-dichlopropionanilide) has been extensively

used to control ALS-R CYPDI and other weeds of rice. Lack of proper

control following propanil spraying was detected in 2012 suggesting

resistance to this herbicide might have also evolved in rice fields. The

objectives of this research were to confirm resistance to propanil,

ascertain resistance levels, and establish the underlying mechanisms

of resistance in CYPDI biotypes collected in rice fields of California.

Our results indicate that a number of CYPDI populations collected in

CA rice fields displayed a high level of resistance to propanil (R/S

ratio equaled 14). When rice cv. M-206 and propanil-susceptible (S)

and –R CYPDI were sprayed with propanil jointly with the insecticide

carbaryl (a known propanil synergist that inhibits propanil

degradation in plants), all plant species except propanil-R CYPDI

experienced significant growth suppression, suggesting propanil

metabolism is not the mechanism of resistance in the R biotypes

used. Interestingly, propanil-R CYPDI biotypes are also cross-

resistant to other PSII-inhibiting herbicides (diuron, atrazine,

bromoxynil, and metribuzin), although resistance to atrazine is weak.

These results suggested propanil resistance might involve the PSII-

inhibitor binding site at the target protein D1 of PSII. Therefore, we

sequenced the herbicide-binding region of the chloroplast psbA gene,

which codes for propanil’s target site (e.g. the D1 protein), where a

valine to isoleucine substitution at amino acid residue 219 was

identified. This mutation had already been found in Poa annua

biotypes resistant to diuron and metribuzin and is not associated

with resistance to atrazine in agreement with our results. Therefore,

unlike resistance in grasses and selectivity in rice - at which

resistance is attributed to enhanced propanil degradation, resistance

to propanil in CYPDI from CA is endowed by a single mutation at the

D1 protein, which affects binding of propanil at its target-site. For

control of propanil-R CYPDI (and given the widespread resistance to

ALS inhibitors in CA rice fields), it is thus necessary to switch

herbicide modes of action away from PSII and ALS inhibitors, and

prevent spread of resistant populations by preventing seed

contamination by performing proper cleaning of tillage and harvest

46

machinery. Further research has also indicated that other herbicides

used in rice are effective against propanil-R CYPDI, such as

carfentrazone, benzobicyclon, and thiobencarb.

Herbicide Resistance in Sprangletop

Two subspecies of sprangletop (Leptochloa fusca spp. fascicularis and

Leptochloa fusca spp. uninervia) are native to California. Preliminary

surveys indicate that there are differences between the two

subspecies in their distribution: fusca is spread throughout rice fields,

and uninervia appears closer to the edges. Only a few herbicides are

available to control sprangletop in California. The two active

ingredients most widely used are clomazone (commercial names

Cerano, Bombard) and cyhalofop-butyl (Clincher). Clomazone is a

DXP synthase inhibitor, and cyhalofop-butyl is an ACC-ase inhibitor.

In the past two years, we received grower field-collected samples that

were tested for resistance (2012 and 2013) to these two active

ingredients. We confirmed independent populations with resistance

to clomazone and cyhalofop-butyl, but have no confirmed cases of

multiple-resistance. All samples tested and confirmed resistant are

from the spp. fusca, not spp. uninervia. Preliminary results indicate

that resistance to cyhalofop-butyl also confers cross-resistance to

quizalofop, but not to clethodim (also ACC-ase inhibitors). Further

research is needed to determine possible mechanisms of resistance.

Abolish (thiobencarb) and Prowl H2O (pendamethalin) used as pre-

emergent herbicides still offer good control in dry-seeded systems,

while Bolero (thiobencarb) offers control in water-seeded continuously

flooded systems.

47

Herbicides used and their active ingredient

% ai lb ai/gal

Abolish (thiobencarb) 84 8.0

Bolero Ultramax (thiobencarb) 15 NA

Butte (benzobicyclon + halosulfuron) 3+0.64 NA

Cerano (clomazone) 5 NA

Clincher (cyhalofop-butyl) 29.6 2.4

Granite SC (penoxsulam) 24 2.0

Granite GR (penoxsulam) 0.24 NA

Grandstand (triclopyr) 44.4 3.0

Halomax (halosulfuron) 75 NA

League MVP (thiobencarb+imazosulfuron) 10+0.43 NA

Londax (bensulfuron-methyl) 60 NA

Prowl H2O (pendimethalin) 42.6 3.8

Regiment (bispyribac-sodium) 80 NA

RiceEdge (propanil + halosulfuron) 60+0.64 NA

Sandea (halosulfuron) 75 NA

Shark H2O (carfentrazone) 40 NA

SuperWham (propanil) 41.2 4.0

Albert J. Fischer, Professor, Weed Science Program, Department of

Plant Sciences; Whitney Brim-DeForest, PhD Student; Rocio Alarcon-

Reverte, Post-doctoral fellow; Rafael Pedroso, PhD Student; Bruce A.

Linquist, Assistant Cooperative Extension Specialist, Department of

Plant Sciences; Chris Greer, Farm-Advisor, Yuba-Sutter Co.; Luis

Espino, Farm Advisor, Colusa-Glenn Co.; Randal G. Mutters, Farm

Advisor, Butte Co.; James E Hill, CE Specialist, Department of Plant

Sciences; Steve Johnson, SRA I; and J. Ray Stogsdill, SRA II, at UCD

and UCCE.

48

ACKNOWLEDGMENTS The generous support of the Rice Field Day and Rice Research

Programs by the following organizations and individuals made this

field day possible. We appreciate their cooperation and support.

FINANCIAL SUPPORT

Dow AgroSciences

Rue & Forsman Ranch Partnership

Farmer’s Rice Cooperative

Associated Rice Marketing Cooperative

K-I Chemical USA, Inc./Kumiai Chemical

California Rice Commission

RiceCo, LLC

R. Gorrill Ranch Enterprises

Koda Farms Milling, Inc.

USA Rice Federation

BUCRA

FMC Corporation

Gowan

ADM Rice, Inc.

American Commodity Company, LLC

California Agricultural Aircraft Association

SunFoods, LLC

Far West Rice, Inc.

AMVAC Chemical Corporation

Colusa Rice Company, Inc.

49

TRUCKS

John Taylor/Wilbur Ellis Company

BUCRA

Delta Industries

Helena Chemical Company

Big Valley Ag Services

PRODUCT/SUPPLIES

Biggs Farming Group (Straw Bales)

Butte County Mosquito & Vector Control District

Brandt (Copper Sulfate Crystals)

John Taylor/Wilbur Ellis Company (Cerano®)

FMC Corporation (Shark H2O®)

RiceCo (Super Wham®)

EQUIPMENT DISPLAY

Valley Truck and Tractor

Holt of California

SWECO