Rice Breeding Program, 2018

 

Kent McKenzie, Director

Virgilio Andaya, director of plant breeding; plant breeder, Clarose medium grains

Teresa De Leon, plant breeder

Shyamal Talukder, plant breeder

Cynthia Andaya, research scientist, DNA marker laboratory

The rice breeding program’s primary research objective is the development of high yielding, superior rice varieties that are commercially competitive in the world market. Other specific breeding objectives include grain quality and milling yield, cold tolerance, seedling vigor, early maturity, strong culm, and disease resistance.

 Virgilio Andaya is director of plant breeding and is responsible for building the breeding and research team and for providing guidance to achieve goals for all grain types and market classes. Cynthia Andaya is in charge of the DNA marker laboratory and the grain quality lab. The labs support all breeding projects with marker-aided selection, genotyping, and DNA fingerprinting. Teresa De Leon joined the breeding team in January 2018 and also temporarily took charge of rice disease screening and the quarantine of rice introductions. Shyamal Talukder joined the breeding program in March 2018 and was appointed the liaison with Southern U.S. breeding programs. Director Kent McKenzie oversees administration of the Rice Experiment Station, providing logistical support and guidance on variety releases, market evaluation, funding, and recommendations to the board of directors. He is also involved in the discovery and evaluation of novel sources of herbicide resistance.

Breeding nurseries

Favorable weather in spring 2018 allowed for planting rice early in the season. Drill seeding of the second-generation maintenance nursery and disease nursery took place between May 5 and May 12. Water seeding of progeny rows, preliminary and advanced tests, and other breeding lines began May 14 and was completed May 25.

A total of 383 entries were evaluated in the advanced yield tests and 873 entries in the preliminary yield tests. Preliminary yield tests are the initial step of replicated large-plot testing for experimental lines. Superior entries will be advanced in 2019 statewide yield tests.

The breeding nursery included 38,976 water-seeded pedigree rows, 832 drill-seeded second-generation plots, and 13,200 drill-seeded seed maintenance rows. A total of 1,165 crosses were made for rice improvement, bringing the total to 50,208 since 1969. Crosses made in early spring 2018 were grown during the summer at RES to produce second-generation seed. Crosses made in summer were planted in the Hawaii winter nursery or in the RES greenhouse to accelerate the selection process.

Foundation seed headrows were grown for breeder seed of A-202, Calaroma-201, M-210, M-104, and Calamylow-201. Headrows of experimental line 10Y2043, released as S-202 in early 2019, as well as headrows of 12Y2175 and 14Y1006, recommended for foundation seed increase, were also grown.

The 2018–2019 Hawaii winter nursery consisted of 7,860 regular rows (including checks), 600 first-generation transplanted rows, and seed multiplication plots for six ROXY™ lines. The rows were dry seeded between October 30 and November 1. First-generation seeds were planted October 30, while seedlings were transplanted December 10. Selection and harvest was set for April 2019, with seed to be returned for processing and planting in the RES breeding nursery.

The San Joaquin cold-tolerance nursery was planted in cooperation with a local grower. This three-acre, drill-seeded nursery included 3,600 rows, and 405 second-generation plots. Weed control was good, although damage from geese caused some stand establishment problems. Minimal cold-induced blanking was observed in the rows and the second-generation populations.

Shyamal Talukder joined the staff of the Rice Experiment Station as a plant breeder in 2018.

Statewide yield tests

Statewide yield tests were conducted in grower fields and at the RES in 2018 to evaluate promising advanced selections from all three maturity groups—very early, early, and intermediate/late. More details can be found in in the Rice Variety Trials section of this annual report.

Calrose medium grains

The predominant rice varieties planted in California are medium grains, commercially and internationally known as Calrose rice, and account for about 90% of California rice acreage. Breeding for medium grain rice comprises about half the rice breeding program. A significant portion of this project is devoted to premium quality medium grains.

The main goal of the medium grains breeding project is to develop new rice varieties with high, stable grain and milling yields without sacrificing the excellent grain quality of the Calrose varieties. Breeding materials are planted mostly by hand at the RES breeding nursery the second Monday in May, while the second-generation nursery and seed maintenance plots are drill planted in the first week of May. Seed increase and generation advance also take place at the Hawaii winter nursery.

Check variety performance

Advanced line 12Y3097 released as M-210

In 2018 the advanced breeding line 12Y3097 was released as a new variety, M-210. It is a blast-resistant, high yielding, early maturing, glabrous Calrose medium grain. It contains the Pi-b gene that confers resistance to the blast pathogens present in California. It heads earlier than its predecessor, M-208, and is similar to M-206. It has shown superior milling yields.

M-210 is 99% genetically similar to M-206. It is the progeny of one of the M-206 blast-resistant isolines containing individual blast-resistant genes developed with marker-aided backcrossing and selection. This line is a replacement for M-208, which contained the Pi-z gene found to be ineffective against the IB-1 blast strain in California. The line performed similarly to M-206 in grain yield, milling characteristics, and other agronomic traits. The overall grain yield of M-210 across 43 statewide experiments conducted between 2013 and 2017 averaged 9,300 pounds/acre, compared to 9,370 pounds/acre for M-206 and 8,910 pounds/acre for M-208.

Milling and quality characteristics are very close to M-206 and M-208. All three have low gel type typical of Calrose medium grains. Cooking characteristics are similar to M-206. Cooking quality evaluations of M-210 have been favorable. It can be comingled with other Calrose varieties.

Calrose varieties in commercial production are used as checks in preliminary and advanced yield tests. In 2018, these included M-105, M-205, M-206, M-209, M-210, and M-104. Released in 2015, M-209 continues to be the top-yielding check variety, with an average grain yield of 10,040 pounds/acre in 2018. M-209 is adapted to warmer areas and may not perform as well in cooler regions of rice production.

Promising medium grains

Thirteen promising lines showed higher yield compared to check varieties M-104 and M-205 in 2018 statewide yield tests. Two advanced lines that performed well in the 2017 tests, 15Y3171 and 15Y2153, were entered into testing for all three maturity groups, averaging 10,840 pounds/acre and 10,530 pounds/acre, respectively. In the intermediate/late group, a new entry, 17Y3158, had an excellent yield of 11,460 pounds/acre.

Line 12Y2175 advances to seed increase

Premium-quality medium grain entry12Y2175 has been recommended for foundation seed increase in 2019 and has consistently shown a yield advantage over M-206, M-205, and M-209. In 2018, it was once again the top yielder at RES, with an average grain yield of 11,030 pounds/acre.

On average, this advanced line heads10 days later than M-206 and two days later than M-209. Seedling vigor is similar to check varieties. It stands 5 cm taller than M-105 and M-209, is lodging-resistant but is slightly more sensitive to cold stress than check varieties. It is susceptible to stem rot.

Milled rice grains of 12Y2175 are heavier and slightly wider than M-209, while grain length and length/width ratio are in between M-206 and M-209 and can be co-mingled with other Calrose rice varieties.

Milling yield of 12Y2175 when harvested above 19% grain moisture averaged 65/69 (head/total), compared to 65/70 for M-206 and 64/69 for M-209. Those figures dropped at harvest moistures below 19%. Internal and external evaluations have been favorable, indicating acceptable market quality.

Average grain yield and agronomic characteristics of medium grain check varieities grown at the Rice Experiment Station in 2018 for the statewide variety trials
Variety Grain Yield
(lbs/ac)
Harvest MC% Seedling vigor Days to Heading Plant Height (cm) Lodging (percent)
M-104 7,960 15.7 4.9 70 96 28
M-105 9,100 17.7 4.9 73 99 20
M-205 9,240 18.4 4.9 82 96 0
M-206 9,290 18.5 4.9 75 103 30
M-209 10,040 19.5 4.8 80 100 0
M-210 9,090 18.4 4.9 75 99 25

 

Long grains

The long grain breeding project focuses on four major rice types—conventional, jasmine, basmati, and aromatics. Milling and cooking quality improvements of conventional long grains and specialty types remain major priorities, followed by resistance to cold-induced blanking and other agronomic and disease resistance traits.

Conventional long grains

In conventional long grains, extensive cooking quality screening and selection efforts have eliminated the majority of texture softness from California long grain breeding material. Consequently, the primary focus is on milling yield and cold tolerance.

L-206 has been the standard check since its release in 2006. It is an early maturing, high yielding, conventional long grain with good cooking quality. L-207, released in 2016, is the newest conventional long grain. It is a high yielding, intermediate height, and early maturing variety with Southern long grain cooking quality. It is adapted to most areas except the San Joaquin region. Its head rice yields have been a little higher than L-206. L-207 has lower stem rot and aggregate sheath spot resistance scores.

Advanced line 15Y84 released as Calaroma-201

A jasmine-type long grain line, 15Y84, was released in 2018 as Calaroma-201 (the first of its kind from RES). It is a high yielding, semidwarf, early maturing, slightly pubescent, aromatic developed as an alternative to imported Thai jasmine. Its area of adaptation is similar to L-206, but it is not recommended for cooler locations.

Calaroma-201 first entered preliminary statewide testing as 15Y84 in 2015. Its overall grain yield across 22 experiments averaged 9,450 pounds/acre, compared to 9,310 pounds/acre for L-206 and 8,890 pounds/acre for A-202. It has an overall three-year yield advantage of 6.3% over A-202 and 1.5% over L-206.

Milled grains of Calaroma-201 are lighter, longer, and narrower than L-206 and A-202. The head rice yield samples harvested between 19% and 21% moisture were 60/67 (head/total), compared to 61/70 for L-206 and 61/68 for A-202.

The mean amylose content of Calaroma-201 is 15.76%, compared to 22.41% for L-206 and 22.38% for A-202. Having a low amylose content and low gel type, Calaroma-201 cooks softer and stickier than the conventional long grains typical of a jasmine-type rice. Its level of aroma is similar to a typical aromatic long grain, but the taste characteristics are closer to Thai jasmine quality. It earned favorable taste quality ratings from evaluations by Thai jasmine consumers.

 

The advanced conventional long-grain line, 14Y1006, an early maturing sister line of L-207, has been recommended for seed increase. It was evaluated in the three maturity groups and compared to L-206 and L-207.

Overall results indicate that 14Y1006 is an excellent high yielding conventional long grain with a 10% to 12% yield advantage over L-206 in all locations, and has a 2% to 5% higher yield than L-207. Mean heading is similar to L-206 at 74 days. It has shown improved lodging resistance, blanking resistance, milling yield, and cooked grain texture.

In addition to 14Y1006, several other promising lines produced high yields and will be advanced for further evaluation.

Short grains

The short grain project includes conventional short grains and specialty types such as waxy rice, low amylose short grains, waxy short grains, Arborio types, and premiums. New lines are bred and selected for improved, stable grain yield and yield-related traits, milling and cooking quality, blanking resistance, lodging resistance, very early to early and uniform maturity, short flowering duration, and resistance to diseases.

The project is approximately 30% conventional short grains, 35% waxy, 20% premium short grains, 10% Arborio, and 5% low amylose. 

Short grain yield tests

Experimental lines in nurseries and yield tests are compared to standard short grain check varieties:

  • S-102, released in 1996, is the standard short grain check. It is very early maturing, with large seeds, pubescent, and has good cold tolerance.
  • Calhikari-202, released in 2012, is the latest premium quality variety. It is early, short, pubescent, yields higher than Calhikari-201, has better eating quality, smaller grains, and higher milling yields.
  • Calmochi-203, released in 2015, is the latest waxy or sweet rice. It is a high yielding, glabrous, early maturing variety released as an alternative to Calmochi-101.
  • Calamylow-201, released in 2006, is a low amylose variety developed from Calhikari-201.
  • 89Y235 is a RES germplasm release with bold grains.
  • In 2018 statewide yield tests at RES, grain yield of Calmochi-203 was the highest at 9,430 pounds/acre, with Calhikari-202 at 8,390 pounds/acre. Grain yield of S-102 and Calhikari-201 were 8,195 pounds/acre and 8,203 pounds/acre, respectively. Calamylow-201 was the lowest at 6,443 pounds/acre.

    Advanced line 10Y2043 released as S-202

    Line 10Y2043, a conventional short grain, was approved for release as S-202 with limited foundation seed being released to seed growers in 2019. It is a very high yielding, early maturing semidwarf, temperate japonica. Some of the notable varieties in its pedigree include S-102, Calpearl, Calmochi-101, and M-102. Line 10Y2043 is an excellent alternative to S-102 in terms of grain yield and quality and is acceptable to the short grain market, as indicated by favorable internal and external quality evaluations.

    Line 10Y2043 consistently outperformed S-102 across the state, with an average yield of 10,185 pounds/acre and an average yield advantage of 16% over S-102 for three years.

    Seedling vigor is similar to S-102, but plant height is shorter by 4 cm on average. Lodging resistance is nearly the same. In all locations, 10Y2043 required an average of 83 days to flower, two days later than S-102.

    Grains of 10Y2043 are smaller and lighter than S-102. They are also shorter and narrower but have a similar length/width ratio. Caution should be observed when comingling the two if uniformity of a milled rice product is desired. In 2017, milling data showed the head rice yield of 10Y2043 harvested at 19% to 22% grain moisture averaged 61/67 (head/total), compared to 57/67 for S-102. At moistures below 19%, milling yield was 61/70 for 10Y2043 and 57/68 for S-102. In 2018, milling yield at 16% to 19% moisture content was 52/70 for 10Y2043 and 52/68 for S-102.

    Grain qualities such as apparent amylose content, protein content and gel type of 10Y2043 and S-102 were compared. 10Y2043 had slightly lower amylose and higher protein content than S-102. Gel type of both varieties is low. Cooking and sensory evaluations by panelists from marketing organizations indicate overall acceptability of 10Y2043 similar to S-102.

    Over a two-year period at the San Joaquin cold tolerance nursery, 10Y2043 consistently showed a higher cold tolerance than S-102, as reflected in a lower percent blanking. However, greenhouse experiments suggest that they have comparable levels of blanking.

    Disease reactions were monitored for several years. On average, both S-102 and 10Y2043 are susceptible to stem rot, and moderately tolerant to aggregate sheath spot and blast diseases.

    Conventional short grains

    In addition to 10Y2043, three advanced lines and three preliminary lines in yield trials showed higher yield over S-102. The six lines on average showed yield advantages of 500 pounds/acre to 2,000 pounds/acre in the RES yield tests. In the statewide tests, the six lines showed an average 12% yield advantage over S-102, with yields ranging between 9,160 pounds/acre to 9,920 pounds/acre.

    Specialty short grains

    Premiums—Significant effort goes into evaluating advanced lines for grain and cooking quality for short grain premium quality. Based on yield and agronomic characteristics, at least six lines in the advanced yield trial are promising lines for short grain premium quality. Seedling vigor for all six lines were either similar to or better than the Calhikari-202 and headed in the range of 76 to 80 days after planting. They show superior yield potential and evaluation of essential premium cooking performance.

    Waxy—Calmochi-203 was released in 2015 to give growers an alternative to Calmochi-101 (released in 1985). CM-203, a high yielding, glabrous, early maturing waxy variety, continues to outperform CM-101 in terms of grain yield and seedling vigor and is receiving limited market acceptance. In 2018, two promising lines showed better yield and agronomic characteristics compared to either of the current varieties.

    Low amylose and Arborio types—Breeding efforts to develop low amylose short grains and Arborio short grains continue at a limited level. Experimental line 15Y2100 is a lodging resistant, high yielding low amylose line with an average yield ranging from 9,500 pounds/acre to 9,600 pounds/acre, a 33% to 48% yield advantage over the specialty type Calamylow-201. It has slightly higher amylose content and heads two days later. It has gone out for external quality evaluations.

    Some bold grains or Arborio-type rice are being evaluated. The most promising material in the pipeline for short bold grains is 16Y2058, with a yield advantage of 300 pounds/acre to 400 pounds/acre over the 89Y235 check. Field evaluation of 16Y2058 indicates that it has better seedling vigor and is more lodging resistant than 89Y235.

    DNA marker laboratory

    The DNA marker laboratory supports the different breeding programs and special projects. The lab is involved in marker-aided selection for blast resistance, grain quality, aroma, and herbicide resistance; DNA fingerprinting and purity testing of advanced lines; genetic mapping of stem rot resistance genes and herbicide tolerance to oxyfluorfen; and the development of mutant populations using both irradiation and chemical mutagenesis. Emphasis varies from year to year depending on the needs of the breeding program.

    Marker-aided selection

    Marker-aided selection for both blast resistance and grain quality is now a routine part of work in the DNA marker laboratory. The lab played a major role in the release of M-210, which has wider blast resistance than M-208. Other markers are being used to predict grain quality parameters in the long grain program.

    Most of the marker-aided selection work in 2018 focused on developing herbicide tolerance with micro-satellite markers and single nucleotide polymorphisms (SNP) markers to select for oxyfluorfen tolerance in rice.

    In 2018, about 1,400 breeding materials and 400 headrows of 17Y3000 were analyzed in the DNA lab for herbicide tolerance using SNP markers. Selected materials were advanced to the next generation by breeders.

    DNA fingerprinting

    Another important function of the DNA lab is to assist in variety identity and purity assessment—DNA fingerprinting that distinguishes medium grains, long grains, and short grains.

    In 2018, 129 markers were surveyed for fingerprinting of materials grown for headrow purification. About 2,200 headrows consisting of advanced lines and varieties were evaluated with eight markers. Approximately 21,200 data points were generated. Looking at the fingerprint profile of each headrow is important in deciding which materials are advanced to the next generation. A-202 foundation samples were also analyzed for purity.

    ROXY™ materials planted in the greenhouse and the field were also fingerprinted for identity. As the ROXY™ trait is being transferred to different varieties, fingerprint profiles can distinguish resistant plants in different genetic backgrounds.

    The DNA lab also received requests from different entities for identity and purity issues. Growers submitted leaf samples for identification of the off-types in either heading days or appearance. Off-types were also submitted to the lab for analysis of potential weedy red rice contamination.

    Herbicide resistance

    The DNA lab was tasked with determining the genetics of the herbicide tolerance trait and ultimately the genetic location of herbicide resistance.

    Teresa De Leon joined the breeding team in 2018 and also temporarily took charge of rice disease screening and the quarantine of rice introductions.
    Genetic mapping studies identified the location of herbicide tolerance with a multipronged approach. This fine mapping effort narrowed the region of interest. Two independent mutations on the same gene are probably responsible for oxyfluorfen tolerance. Efforts to confirm the candidate gene are continuing by evaluating mutations in other rice germplasm. Research also is underway to measure herbicide response differences between tolerant lines and wild types.

    Detailed investigations of the genetics of the ROXY™ trait will be useful in understanding the tolerance mechanism, supporting intellectual property protection, and the eventual commercialization of oxyfluorfen resistant rice as a weed control tool for growers.

    Stem rot resistance

    The ultimate goal of mapping stem rot resistance is to find tightly linked markers that can be used for marker-aided selection (MAS) by the different breeding programs. Teresa De Leon is working with the DNA lab to continue genetic studies of stem rot resistance.

    Using recombinant lines from a cross between 87Y550 and M-206, the DNA lab has started generating marker data. So far, this research has genotyped recombinant inbred lines (RIL) with 53 markers and will continue to add more markers to focus on rice chromosomes. Genetic analyses will again be done using marker data and the stem rot scores of the RIL mapping population.

    With consistent phenotyping and genotyping, markers associated with stem rot resistance will be more robust and useful in future MAS work.

    Rice pathology

    The rice pathology project is an integral part of the rice breeding program. Research in this area and breeding are focused on developing rice varieties with resistance to stem rot, aggregate sheath spot, and blast diseases. Kernel smut is another, more recent, area of research.

    Stem rot

    The RES continues work on stem rot with Teresa De Leon and Cynthia Andaya currently leading those efforts. Several greenhouse and field experiments were conducted in 2018.

    In a stem rot greenhouse experiment, 185 recombinant inbred lines and 52 second-generation lines, developed from a cross between M-206 and 87Y550, were evaluated.  M-206 is susceptible to stem rot infection, while 87Y550 is a resistant line. Plants were grown in pots with standard soil fertilization.

    Greenhouse evaluations indicated that 26 of the recombinant lines and four of the second-generation lines showed resistance to stem rot. Only three of the recombinant lines were resistant to stem rot in field tests. The low correlation between greenhouse evaluations and field screening is a reflection of the complexity of the disease. Although greenhouse experiments are necessary for stem rot screening, field conditions are better for disease development and evaluating resistance.

    All variety checks in field evaluations scored susceptible to stem rot except for Calmochi-101, which showed a moderate stem rot resistance score. Seven lines in the advanced yield trials showed resistance. Two lines from the South showed high resistance in field evaluations.

    Blast

    The first RES blast resistant variety, M-207, was released in 2005, followed by M-208 in 2006. However, symptoms of the blast disease were observed on M-208 in 2009. Further research determined the existence of a new, significantly different race of the fungus. This led to the development of recently released M-210.

    Aggregate sheath spot

    A backcross program begun in 2005 aims to transfer aggregate sheath spot resistance genes from Teqing, Jasmine 85, and MCR10277 into M-206 and L-206. Breeding lines developed in those crosses were advanced in the greenhouse and in the field. Some lines show resistance equivalent to that found in wild species. These materials have been put in cold storage for future use.

    Quarantine introductions

    The building blocks for any breeding program are cultivars with traits desirable in commercial production. In 2017, 200 lines from the Southern U.S. were received for evaluation and use in the breeding program at the Rice Experiment Station. Evaluation of these lines is continuing.

    In 2018, another 237 lines were received and quarantined in the laboratory. Clean seedlings were grown in the greenhouse. After two cycles of planting in the greenhouse, clean seeds were harvested and will be planted in the 2019 disease nursery for field evaluation.

    All plant introductions grown and released for breeder use are done so under procedures developed and approved by the U.S. Department of Agriculture and the California Department of Food and Agriculture to prevent introduction of exotic insect pests and diseases, as well as weedy red rice in California.

    Herbicide resistant rice

     ROXY™, a non-GMO rice trait providing tolerance to the herbicide oxyfluorfen, has been identified in the most widely grown Calrose variety, M-206. Four years of research in multiple locations shows that oxyfluorfen applied preplant in a water-seeded system provides high levels of rice weed control with the ROXY™ trait. It is also effective in drill-seeded rice with a preplant and preflood application and may have potential in other rice growing regions.

    A provisional U.S. patent for this trait was filed in 2016. The ROXY™ trademark was granted in September 2018. Registration and commercialization of oxyfluorfen with ROXY™ for rice weed control is being pursued with Albaugh, LLC, which currently markets oxyfluorfen.

    In 2018, efficacy studies funded by the Rice Research Trust were conducted in grower fields in Glenn, Colusa, and Sutter counties. Genetic mapping, candidate gene identification/confirmation, and tolerance mechanism research is in progress at the Rice Experiment Station. The breeding program is transferring this trait to other grain types, with the first materials included in 2018 large plot yield tests at RES. Headrows and a small seed increase of 17Y3000 at RES yielded 10,700 pounds/acre and is providing seed for 2019 research.

    In 2018, weed control studies in the breeding program included large plot studies of oxyfluorfen rate and seeding rate experiments under water-seeded and drill-seeded experiments with 17Y30000.

    In the water-seeded experiment, soaked seed was broadcast on treated soil and then flooded. Although the stands were initially very thin, the rice did recover and produced respectable yields with good weed control. There was a significant delay in heading with increased rates of oxyfluorfen but no significant effect on yield by herbicide or seeding rate in this experiment.

    In the drill-seeded experiment, there were no emergence or stand differences over herbicide rates or in heading dates. Yields were good.

    Breeding with genomic selection

    Almost all the national and international rice breeding programs use conventional breeding schemes—the pedigree method, a very time-consuming approach. Advances in molecular genetics have been incorporated into plant breeding programs in recent years. However, this approach is limited by the number of useable molecular markers.

    A new approach called genomic selection shows enormous potential to significantly enhance breeding efficiency and is being integrated into the rice breeding program. In 2018, a rice population was developed to analyze the variability of all the advanced lines from the last five years. This population consists of 210 medium grains, 64 long grains, 73 short grains, and 13 compound grain types.  All the varieties released by RES are included in this population.

    Boxes:

    Advanced line 12Y3097 released as M-210

    In 2018 the advanced breeding line 12Y3097 was released as a new variety, M-210. It is a blast-resistant, high yielding, early maturing, glabrous Calrose medium grain. It contains the Pi-b gene that confers resistance to the blast pathogens present in California. It heads earlier than its predecessor, M-208, and is similar to M-206. It has shown superior milling yields.

    M-210 is 99% genetically similar to M-206. It is the progeny of one of the M-206 blast-resistant isolines containing individual blast-resistant genes developed with marker-aided backcrossing and selection. This line is a replacement for M-208, which contained the Pi-z gene found to be ineffective against the IB-1 blast strain in California. The line performed similarly to M-206 in grain yield, milling characteristics, and other agronomic traits. The overall grain yield of M-210 across 43 statewide experiments conducted between 2013 and 2017 averaged 9,300 pounds/acre, compared to 9,370 pounds/acre for M-206 and 8,910 pounds/acre for M-208.

    Milling and quality characteristics are very close to M-206 and M-208. All three have low gel type typical of Calrose medium grains. Cooking characteristics are similar to M-206. Cooking quality evaluations of M-210 have been favorable. It can be comingled with other Calrose varieties.

    Advanced line 15Y84 released as Calaroma-201

    A jasmine-type long grain line, 15Y84, was released in 2018 as Calaroma-201 (the first of its kind from RES). It is a high yielding, semidwarf, early maturing, slightly pubescent, aromatic developed as an alternative to imported Thai jasmine. Its area of adaptation is similar to L-206, but it is not recommended for cooler locations.

    Calaroma-201 first entered preliminary statewide testing as 15Y84 in 2015. Its overall grain yield across 22 experiments averaged 9,450 pounds/acre, compared to 9,310 pounds/acre for L-206 and 8,890 pounds/acre for A-202. It has an overall three-year yield advantage of 6.3% over A-202 and 1.5% over L-206.

    Milled grains of Calaroma-201 are lighter, longer, and narrower than L-206 and A-202. The head rice yield samples harvested between 19% and 21% moisture were 60/67 (head/total), compared to 61/70 for L-206 and 61/68 for A-202.

    The mean amylose content of Calaroma-201 is 15.76%, compared to 22.41% for L-206 and 22.38% for A-202. Having a low amylose content and low gel type, Calaroma-201 cooks softer and stickier than the conventional long grains typical of a jasmine-type rice. Its level of aroma is similar to a typical aromatic long grain, but the taste characteristics are closer to Thai jasmine quality. It earned favorable taste quality ratings from evaluations by Thai jasmine consumers.