|Rice Variety Trials - 2010
Project Leader and Principal Investigators
James E. Hill,
Seventeen on-farm rice variety evaluation trials were conducted throughout
the rice growing regions of California in 2010 by UC Cooperative Extension
scientists in collaboration with plant breeders at the Rice Experiment
Station. Standard varieties are 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 Rice Experiment Station, two from each maturity group. Average yields across varieties and locations in the advanced-line tests ranged from 8,300 pounds/acre in the very early trials to 9,590 pounds/acre in the early tests. In the intermediate-to-late tests, the advanced lines yielded 9,150 pounds/acre.
Frequent spring rains delayed field preparation and planting by seven to 10 days. Several advanced lines in 2010 produced high yields, and demonstrated advances toward other important breeding goals, such as disease resistance and grain quality.
Testing advanced and preliminary lines under farmer field 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 rice breeders at the Rice Experiment Station conducted six additional tests—two from each of the three maturity groups. Agronomic performance summaries follow.
Very early maturity
Eleven advanced breeding lines and seven commercial varieties were compared in four very early advanced breeding tests. Commercial varieties at each location included S-102, CH-201, CM-101, M-104, M-202, M-206, and L-206. Additionally, 31 experimental lines and three commercial varieties were tested in the preliminary trials at each location.
Grain yields in the advanced tests averaged 10,170 pounds/acre at RES, 7,070 pounds/acre at Sutter, 7,920 pounds/acre at Yolo, and 8,140 pounds/acre at San Joaquin. Over all locations, the highest yielding entries were advanced long grain 06Y575 (9,690 pounds/acre), advanced short-grain 05Y343 (8,860 pounds/acre), and M-206 (8,740 pounds/acre). Other top-yielding commercial varieties included L-206, CM-101, S-102, and M-202. Averaged across locations, yields in the preliminary tests ranged from 5,180 pounds/acre to 9,370 pounds/acre.
The average number of days to 50% heading was seven days more than in 2009. Spring rains delayed field preparation and planting, and prevented a significant percentage of projected acreage from being planted. Cooler than normal daytime and nighttime temperatures increased the number of days to 50% heading and caused a slight increase in lodging.
Comparing commercial standard entries over a five-year period and across locations, M-206, L-206, and S-102 were the highest yielding varieties at 9,490 pounds/acre, 9,390 pounds/acre, and 9,370 pounds/acre, respectively.
Eleven advanced lines and eight commercial varieties were compared in four early tests. Preliminary tests included four commercial varieties and 30 preliminary lines evaluated in separate tests at each location. Commercial varieties at each location included CH-201, CM-101, Koshihikari, S-102, M-202, M-205, M-206, M-208, A-201, CT-202, and L-206.
Yields in the advanced lines averaged 10,490 pounds/acre at RES, 8,160 pounds/acre at Butte, 9,260 pounds/acre at Yuba, and 10,460 pounds/acre at Colusa. Advanced short grain 05Y343 was the highest yielding entry (10,630 pounds/acre) averaged over four locations in 2010. Other entries with yields averaging greater than 10,000 pounds/acre were long grains 06Y575 and 08Y1092, and medium grains 05Y471 and M-206.
Days to 50% heading ranged from 89 days in Yuba County and at the Rice Experiment Station to 94 days at the Colusa County test site. M-206 headed at 85 days at Yuba and 91 days at Colusa.
Over a five-year period and across locations, M-205 continues to be the highest-yielding commercial variety at 9,460 pounds/acre, followed by M-206 at 9,320 pounds/acre.
Six advanced lines and six commercial varieties were compared in three intermediate-to-late tests. Preliminary tests included two commercial varieties and 22 preliminary lines evaluated in separate tests at each location. Commercial varieties at each location included CH-201, Koshihikari, M-202, M-205, M-402, L-206, and CT-202.
Yields in the advanced lines averaged 9,940 pounds/acre at the RES, 8,380 pounds/acre at Glenn, and 9,130 pounds/acre at Sutter. The 2010 advanced over-location yield was 50 pounds/acre less than the 2009 season average.
Across locations M-205 was the highest yielding commercial variety (9,810 pounds/acre), followed by L-206, and M-202. The long grain Newrex entry 06Y575 was the highest yielding advanced entry at 10,620 pounds/acre.
Average days to 50% heading ranged from 97 days at the RES and Sutter locations to 100 days at the Glenn County location. As in the previous five years, M-402 took the longest time to reach maturity among the commercial varieties (110 days).
Over a five-year period and across locations, M-205 continues to be the highest-yielding commercial variety in this group at 9,330 pounds/acre. M-205 and L-206 produced 106 percent of the M-202 yield on average over the last five years.
Twitchell Island study
Rice variety testing continued in 2010 on Twitchell Island in the western part of the Sacramento-San Joaquin Delta to evaluate rice culture for its potential to prevent soil subsidence.
Four commercial varieties with the best potential to tolerate cold temperatures (Calmochi-101, S-102, M-104, and M-206) were compared in one-acre plots replicated three times. Small test plots also examined S-102, M-202, L-206, and 11 advanced cold-tolerant lines to provide rice breeders with information about rice grown under very cold conditions. A third test replicated four times with M-104 was added to compare water-seeding and drill-seeding methods.
The results again showed that varieties with good cold tolerance such as Calmochi-101 would produce reasonable yields. Calmochi-101 ranked at the top (7,580 pounds/acre), followed by S-102 (6,970 pounds/acre), M-104 (6,490 pounds/acre) and M-206 (4,467 pounds/acre). Calmochi-101 is well known as the most cold tolerant of commercial California varieties and has become the standard to measure this trait against other varieties and advanced lines.
Yields were variable in these variety trials. Clearly, blanking and delayed plant development due to cold temperatures was a negative factor in achieving yields. The average time to 50% heading for these very early varieties was 118 days—10 days later than the average days to heading for intermediate-to-late maturing varieties in Sacramento Valley tests. This again demonstrates the challenge of growing rice in this environment.
In the newly added third trial, M-104 on average yielded 2,300 pounds/acre higher water-seeded than drill-seeded. However, improved uniformity in field conditions are needed to improve the reliability of test results.