Rice Variety Trials, 2013


Project Leader

James E. Hill, UCCE rice specialist, Dept. of Plant Sciences, UC Davis

Seventeen on-farm rice variety evaluation trials were conducted throughout the rice-growing regions of California in 2013 by UC Cooperative Extension scientists in cooperation with plant breeders at the Rice Experiment Station (RES). Standard varieties were compared with preliminary and advanced lines in these tests to measure performance across a range of environments, farmer practices, and disease levels.

Six similar tests were conducted at the RES in Biggs, two from each maturity group. Average yields across varieties and locations in the advanced-line tests ranged from 9,160 pounds/acre in the very early trials to 9,020 pounds/acre in the early tests. In the intermediate-to-late tests the advanced lines’ average yield was 8,870 pounds/acre.

Field preparation was completed earlier than normal because of the relatively dry spring. Planting also was completed earlier than normal. However, several areas experienced delayed water deliveries in 2013, resulting in large areas being planted in a short period of time. Several advanced lines in 2013 produced high yields and demonstrated advances toward other important breeding goals, such as disease resistance, specialty types, and grain quality. Testing advanced and preliminary lines under a variety of conditions remains a critical aspect of releasing varieties adapted to changing cultural practices, markets, and pests.

Rice Variety Evaluations

Eight uniform advanced breeding line trials and eight preliminary breeding line trials were conducted throughout the major rice-producing areas of California. The RES rice breeders conducted six additional tests—two from each of the three maturity groups. Many of the experimental lines have been tested and screened in previous years and advanced for further testing. Agronomic performance summaries are reported below.

Very Early Maturity

Seven advanced breeding lines and nine commercial varieties were compared in four very early advanced tests. The preliminary tests included four commercial varieties and 32 preliminary lines evaluated in separate tests at each location. Commercial varieties at each location included S-102, CA-201, CH-201, CH-202, CM-101, M-104, M-105, M-202, M-205, M-206, M-208, M-402, and L-206.

Grain yields in the advanced tests averaged 9,160 pounds/acre overall, 9,500 pounds/acre at RES, 9,740 pounds/acre at Sutter, 9,340 pounds/acre at Yolo, and 8,050 pounds/acre at San Joaquin. The three highest-yielding entries on average were advanced medium-grain line 08Y3269 (9,790 pounds/acre), advanced long-grain line 11Y1005 (9,730 pounds/acre), and advanced short-grain line 09Y2036 (9,710 pounds/acre). Top-yielding commercial varieties included M-105, L-206, M-104, and M-206. Averaged across locations, yields for lines in the preliminary tests ranged from 7,300 pounds/acre to 10,290 pounds/acre.

Average grain moisture at harvest, number of days to 50% heading, and lodging increased in 2013 compared to 2012 (2.8%, three days, and 14%, respectively). Seedling vigor and plant height were essentially the same as in 2012. As previously noted, field preparation and planting were earlier than normal. Relatively dry weather throughout the growing season resulted in a timely harvest and reasonably good grain quality.

Comparing commercial standard entries over a five-year period and across locations, M-206, L-206, and M-104, were the highest-yielding varieties at 9,389 pounds/acre, 9,134 pounds/acre, and 9,125 pounds/acre, respectively.

Early Maturity

Ten advanced breeding lines and eight commercial varieties were compared in four early advanced tests. Preliminary tests included seven commercial varieties and 29 preliminary lines evaluated in separate tests at each location. Commercial varieties at each location included CA-201, CH-201, CH-202, CM-101, S-102, M-105, M-202, M-205, M-206, M-208, M-402, A-201, A-301, CT-202, and L-206.

Twitchell Island study

Rice variety testing continued in 2013 on Twitchell Island in the western part of the Sacramento–San Joaquin Delta. The overall purpose for examining rice production in this region is to evaluate a flood-tolerant crop that could prevent subsidence of the area’s organic soils from oxidation caused by cultivation of upland crops.

A special variety test continues on Twitchell Island to determine the feasibility of commercial rice production in an extremely cold environment for rice. The average yield in the cold-tolerance variety trial increased 1,190 pounds/acre (16%) compared to 2012. Average yields ranged from 6,360 pounds/acre to 8,090

pounds/acre. There were no significant differences among the varieties tested. The highest-yielding entry was the short grain CM-101. Other top producers included the advanced medium-grain M-206-Pi-ta2, M-206, and medium grain 12Y113, indicating the potential for short-grain types and medium-grain Calrose types in cold environments.

The average time to 50% heading for these very early varieties was 103 days after planting, 19 days later than the average days to heading for very early-maturing varieties in the Sacramento Valley tests. The delay in maturity, a result of drill planting and the cool environment, demonstrates the challenges of growing rice in this region. Field uniformity and cultural practices are improving as researchers learn how to maximize production under these growing conditions.

Yields in the advanced lines averaged 9,020 pounds/acre overall, 8,810 pounds/acre at RES, 8,950 pounds/acre at Butte, 9,050 pounds/acre at Colusa, and 9,270 pounds/acre at Yuba. Advanced long grain 11Y1008 was again the highest-yielding entry (10,100 pounds/acre) averaged over four locations in 2013. Advanced experimental long grain 09Y1122, medium grain 10Y3703, and medium grain 11Y2138 yielded second, third, and fourth, respectively. Top-yielding commercial varieties included L-206, M-205, M-206, S-102, and M-202. These high-yielding advanced lines indicate that breeders are making good progress in variety development.

Average days to 50% heading ranged from 85 days at the Rice Experiment Station to 90 days at the slightly cooler Yuba County test site. The commercial standard, M-206, headed at 82 days at RES and 87 days in Yuba County. The average yield of M-105 decreased 1% compared to 2012. Eleven experimental lines averaged higher yields than M-105 in preliminary tests.

Over a five-year period and across locations, L-206 was the highest-yielding commercial variety at 9,621 pounds/acre, followed by M-205 at 9,557 pounds/acre and M-206 at 9,418 pounds/acre.

Intermediate-to-Late Maturity

Three advanced experimental lines and seven commercial varieties were compared in three intermediate-to-late tests. Preliminary tests included six commercial varieties and 22 preliminary lines evaluated in separate tests at each location. Commercial varieties at each location included CH-201, CH-202, Koshihikari, M-202, M-105, M-202, M-203, M-205, M-206, M-401, M-402, L-206, A-201, and CT-202. Yields in the advanced lines averaged 8,870 pounds/acre overall, 9,560 pounds/acre at the RES, 8,620 pounds/acre at Glenn, and 8,420 pounds/acre at Sutter. The 2013 advanced over-location yield decreased 410 pounds/acre (11%) compared to the 2012 season average. The average yields at the Rice Experiment Station and Sutter locations decreased 800 
pounds/acre, while increasing 530 pounds/acre at Glenn compared to the 2012 season. M-206 was the highest yielding commercial variety (9,260 pounds/acre), ranking second overall. L-206 and M-205 were the next highest-yielding commercial varieties. The medium-grain, premium quality entry 11Y2183 was the highest-yielding advanced entry across locations at 9,470 pounds/acre.

Average days to 50% heading increased four days compared to 2012. At 110 days, M-401 and M-402 took the longest time to reach maturity among the commercial varieties.

Over a five-year period and across locations M-205 continues to be the highest-yielding commercial variety in this group at 9,459 pounds/acre, followed closely by L-206 at 9,445 pounds/acre. M-205 and L-206 produced 106% and 105% of the M-202 yield on average over the last five years.