Rice Variety Trials, 2020

 

Bruce Linquist, UCCE Rice Specialist, Dept of Plant Sciences, UC Davis

Seven uniform breeding line trials were conducted throughout the rice growing regions of California in 2020 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. Three similar tests were conducted at RES—one from each of the three growing zones. All sites were water seeded.

Average yields across varieties and locations in the advanced-line tests ranged from 9,770 pounds/acre in the early tests (zone 2) to 9,020 pounds/acre in the very early tests (zone 1). In the intermediate/late tests (zone 3), the advanced lines average yield was 9,320 pounds/acre.

Several advanced lines produced high yields, as well as demonstrating important breeding goals aside from yield, such as disease resistance, grain quality, and specialty types. 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

The seven on-farm breeding-line trials consisting of four-replication advanced, two-replication advanced, and two-replication preliminary evaluations were conducted throughout the major rice producing areas of California. The RES breeders conducted three additional tests—one from each of the three growing zones. Many of the experimental lines have been tested and screened in previous years and were advanced for further testing. The RES provided the seed for public varieties and experimental cultivars. No proprietary lines were tested.

Very early maturity tests (zone 3)

Eight commercial varieties and six advanced breeding lines were compared in four four-replication advanced tests. Three commercial and 11 breeding lines were compared in four two-replication advanced tests. The two-replication preliminary tests evaluated five commercial varieties and 23 preliminary lines at each location. Commercial varieties at each location included S-102, S-202, CH-202, CM-101, CM-203, M-105, M-206, M-209, M-210, M-211, A-202, CJ-201, L-207, and L-208.

Grain yields in the four-replication advanced tests averaged 9,320 pounds/acre overall, 9,670 pounds/acre at RES, 9,560 pounds/acre at Sutter, 10,090 pounds/acre at Yolo, and 7,980 pounds/acre at Yuba. The three highest-yielding entries on average were long grain L-207 (10,390 pounds/acre), long grain L-208 (10,340 pounds/acre) and short grain S-202 (9,980 pounds/acre). Top-yielding commercial varieties also included L-207, L-208, S-202, and M-211.

In the two-replication advanced test, the highest yielding experimental line was 18Y117 at 9,820 pounds/acre. The top commercial variety was CJ-201 at 9,580 pounds/acre.

Averaged across four locations, yields for lines in the preliminary tests ranged from 9,760 pounds/acre to 8,420 pounds/acre.

Average grain moisture at harvest was 18.3%, average lodging 21%, average days to 50% heading was 89, average seedling vigor 4.8, and average plant height was about 38 inches. Field preparation and planting were completed early in 2020, with most plantings done before May 10 and all tests planted by May 18. Harvest was completed within the normal time frame, with yields in the four-replication advanced test increasing from 8,790 pounds/acre to 9,320 pounds/acre.

Comparing commercial standard entries over a five-year period and across locations, M-211, M-105, and M-206 were the highest-yielding varieties at 9,254 pounds/acre, 9,173 pounds/acre, and 9,007 pounds/acre, respectively.

Early maturity tests (zone 2)

Eight commercial varieties and six advanced breeding lines were compared in three four-replication advanced tests. Three commercial and 11 breeding lines were compared in three two-replication advanced tests. Two-replication preliminary tests evaluated five commercial varieties and 23 preliminary lines at each location. Commercial varieties at each location included S-102, S-202, CH-202, CM-101, CM-203, M-105, M-206, M-209, M-210, M-211, A-202, CJ-201, L-207, and L-208.

Yields in the four-replication advanced line tests averaged 9,770 pounds/acre overall, 9,710 pounds/acre at RES, 10,110 pounds/acre at Butte, and 9,490 pounds/acre at south Butte. Long grain L-208 was the highest yielding entry at 10,980 pounds/acre when averaged over three locations in 2020. Short grain S-202 (10,590 pounds/acre), long grain 17Y1027 (10,320 pounds/acre), and long grain L-207 (10,320 pounds/acre) yielded second, third, and fourth, respectively. Other top-yielding commercial varieties included M-211, M-209, M-105, M-206, and CH-202.

Average number of days to 50% heading was 87. The commercial standard M-206 averaged 85 days over three locations. In the two-replication advanced test, 18Y117 was the highest yielding experimental line. CJ-201 was the highest yielding commercial variety.

Intermediate/late maturity tests (zone 1)

Eight commercial varieties and six advanced breeding lines were compared in three four-replication advanced tests. Three commercial and 11 breeding lines were compared in three two-replication advanced tests. The two-replication preliminary tests evaluated five commercial varieties and 23 preliminary lines at each location. Commercial varieties at each location included S-102, S-202, CH-202, CM-101, CM-203, M-105, M-206, M-209, M-210, M-211, A-202, CJ-201, L-207, and L-208.

Yields in the four-replication advanced line tests averaged 9,020 pounds/acre overall, 9,720 pounds/acre at RES, 8,630 pounds/acre at Colusa, and 8,720 pounds/acre at Glenn. The 2020 advanced over-location yield decreased 430 pounds/acre (4.6%) compared to the 2019 season average. In the four-replication advanced tests, L-208 was the highest-yielding commercial variety (10,340 pounds/acre), ranking first overall. L-207 (9,950 pounds/acre) and M-209 (9,420 pounds/acre) were the next highest-yielding commercial varieties across locations. The long grain entry 17Y1027 was the highest-yielding advanced entry across all locations at 9,320 pounds/acre.

Average number of days to 50% heading was 85. Medium grain M-211 was the latest variety at 96 days to reach 50% heading at all locations.