Variety Trials - 2009

 

 

 

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Project Leader and Principal  Investigators

James E. Hill,
UC Cooperative Extension Specialist, Dept. of Plant Sciences, UC Davis

 

 

 

Variety evaluation trials were conducted throughout the rice-growing regions of California in 2009 by UC Cooperative Extension scientists in collaboration with plant breeders at the Rice Experiment Station (RES).  These trials perform an essential role in exposing standard, advanced, and preliminary varieties to 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 9,470 pounds/acre in the very early trials to 8,970 pounds/acre in the early tests.  In the intermediate-to-late tests, the advanced lines yielded 9,200 pounds/acre.

Spring rains were light in 2009, allowing for timely field preparation and planting. Several advanced lines in 2009 produced high yields, and demonstrated advances toward important breeding goals, such as disease resistance 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.

Very early maturity

Ten advanced breeding lines and seven commercial varieties were compared in four very early advanced breeding tests.  Commercial varieties at each location included S-102, CM-101, M-104, M-202, M-206, L-205, 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 8,740 pounds/acre at RES, 9,470 pounds/acre at Sutter, 11,530 pounds/acre at Yolo, and 8,130 pounds/acre at San Joaquin.  Over all locations, the highest-yielding entries were advanced long-grains 06Y575 (10,710 pounds/acre), 07Y508 (10,410 pounds/acre), and 08Y1009 (9,910 pounds/acre). Top-yielding commercial varieties included M-206, L-206, M-104, and L-205. Averaged across locations, yields in the preliminary tests ranged from 8,450 pounds/acre to 10,260 pounds/acre.

The average number of days to 50% heading was seven days less than in 2008. Moderate daytime and slightly warmer nighttime temperatures were responsible for accelerating rice plant maturity.

Over a five-year period and across locations, S-102 continues to be the highest-yielding very early variety, followed by M-206 at 9,402 pounds/acre and 9,368 pounds/acre, respectively.

Early maturity

Ten advanced lines and eight commercial varieties were compared in four early tests.  Preliminary tests included four commercial varieties and 33 preliminary lines evaluated in separate tests at each location. Commercial varieties at each location included CH-201, CM-101, S-102, M-202, M-203, M-205, M-206, A-201, CT-202, L-205, and L-206.

Yields in the advanced lines averaged 9,640 pounds/acre at RES, 9,130 pounds/acre at Butte, 8,380 pounds/acre at Yuba, and 8,730 pounds/acre at Colusa. Advanced long grain 08Y1092 was the highest-yielding entry (10,170 pounds/acre) averaged over four locations in 2009. Other consistently high-yielding entries included 08Y1048, L-206, 06Y513, and M-205.

Days to 50% heading ranged from 81 days at the Yuba County site to 89 days at the Colusa County test site.  M-202 headed at 92 days at RES and 96 days at Colusa.

Over a five-year period and across locations, M-205 continues to be the highest-yielding commercial variety at 9,245 pounds/acre, followed by M-206 at 8,817 pounds/acre.

Intermediate-to-late maturity

Eight advanced lines and five commercial varieties were compared in three intermediate-to-late tests.  Preliminary tests included four commercial varieties and 18 preliminary lines evaluated in separate tests at each location. Commercial varieties at each location included CH-201, M-202, M-205, M-402, L-205, L-206, CT-201, and CT-202.

Yields in the advanced lines averaged 9,470 pounds/acre at RES, 10,220 pounds/acre at Glenn and 7,920 pounds/acre at Sutter. The 2009 advanced over-location yield was slightly higher than the 2008 season average. Compared to 2008, average yields were lower at RES and Sutter, while more than 1,500 pounds/acre at Glenn.

L-206 was the highest-yielding commercial variety at 9,290 pounds/acre. M-402 and L-205 were the next highest-yielding commercial varieties across locations. The stem-rot-resistant long grain entry 08Y1154 was the highest-yielding advanced entry at 9,490 pounds/acre.

Days to 50% heading ranged from 90 days at RES and Sutter to 92 days at the Glenn County location. As in the previous four years, M-402 took the longest time to reach maturity among the commercial varieties (average is 104 days).

Over a five-year period and across locations, M-205 continues to be the highest-yielding commercial variety in this group at 9,195 pounds/acre. M-205 and M-402 produced 106% and 99%, respectively, of the M-202 yield on average over the last five years.

Twitchell Island study

Rice variety testing was conducted on Twitchell Island in the western part of the Sacramento-San Joaquin Delta in 2009. This is part of a larger project to evaluate rice culture for its potential to prevent soil subsidence.

Four commercial varieties with the best potential to tolerate cold temperatures (Calmochi-101, M-104, M-202, and M-206) were compared in one-acre plots replicated three times. Small test plots also examined S-102, L-206, and 12 advanced cold-tolerant lines to provide rice breeders with information about rice grown under very cold conditions.

The results showed that varieties with good cold tolerance, such as Calmochi-101, will produce reasonable yields. Calmochi-101 ranked at the top, followed by M-206, M-104, and M-202.

Yields were variable in these variety trials. Cold-temperature blanking and shattering from Delta winds negatively affected yields. The time to heading at this location was on average greater than heading dates for late varieties in the Sacramento Valley, demonstrating the challenges of growing rice in this environment. 

 

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