Rice Variety Trials, 2019

 

Bruce Linquist, UCCE specialist, Dept. of Plant Sciences, UC Davis

Eight on-farm rice variety evaluation trials were conducted throughout the rice growing regions of California in 2019 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—two from each maturity group. Average yields across varieties and locations in the advanced-line tests ranged from 9,540 pounds/acre in the early tests to 8,790 pounds/acre in the very early tests. In the intermediate/late tests, the advanced lines average yield was 9,450 pounds/acre.

Field preparation and planting were mixed because of heavy rain in the middle of May. Rice was planted as late as the second week of June. Several advanced lines in 2019 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

Eight uniform breeding-line trials consisting of four-replication advance, two-replication advance, 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. Agronomic performance for these tests are reported below.

Very early tests zone 3

Ten commercial varieties and four advanced breeding lines were compared in five four-replication advanced tests. Four commercial and 10 breeding lines were compared in five two-replication advanced tests. Two-replication preliminary tests evaluated four commercial varieties and 24 preliminary lines at each location. Commercial varieties at each location included S-102, S-202, CA-201, CH-201, CH-202, CM-101, CM-203, M-104, M-105, M-205, M-206, M-209, M-210, A-202, CJ-201, CT-202, L-206, and L-207.

Grain yields in the four-replication advanced tests averaged 8,790 pounds/acres overall, 9,260 pounds/acre at RES, 9,620 pounds/acre at Sutter, 9,220 pounds/acre at Yolo, 8,470 pounds/acre at south Yolo, and 7,390 pounds/acre at Yuba. The three highest-yielding entries on average were long grain line 14Y1006 (10,170 pounds/acre), long grain L-207 (9,590 pounds/acre), and short grain S-202 (9,380 pounds/acre). Top-yielding commercial varieties included L-207, S-202, L-206, and M-105.

In the two-replication advanced test, the highest yielding experimental line was 18Y117 at 9,400 pounds/acre. The top commercial variety was CM-203 at 9,360 pounds/acre.

Averaged across five locations, yields for lines in the preliminary tests ranged from 9,460 pounds/acre to 6,190 pounds/acre.

Average grain moisture at harvest was 15.8%, average lodging 38%, average days to 50% heading was 88, average seedling vigor 4.8, and average plant height was about 37 inches. Field preparation and planting were mixed, with most of the planting occurring before May15. However, heavy rain in the middle of May caused fields to be delayed in both the Yolo and Yuba trials. Harvest was completed within the normal time frame but yields in the four-replication advanced test were down 6.8% from 2018.

Comparing commercial standard entries over a five-year period and across locations, M-105, M-206, and L-206 were the highest-yielding varieties at 9,158 pounds/acre, 9,060 pounds/acre, and 8,882 pounds/acre, respectively.

Early maturity tests zone 2

Ten commercial varieties and four advanced breeding lines were compared in three four-replication advanced tests. Four commercial and 10 breeding lines were compared in three two-replication advanced tests. Two-replication preliminary tests evaluated four commercial varieties and 24 preliminary lines at each location. Commercial varieties at each location included S-102, S-202, CA-201, CH-201, CH-202, CM-101, CM-203, M-104, M-105, M-205, M-206, M-209, M-210, A-202, CJ-201, CT-202, L-206, and L-207.

The advanced line 12Y2175 was approved for release in early 2020 as a new Calrose variety, M-211. It is perfectly suited for comingling with other calrose types like M-206 and M-209.

Yields in the four-replication advanced line tests averaged 9,540 pounds/acre overall, 9,530 pounds/acre at RES, 9,460 pounds/acre at Butte, and 9,620 pounds/acre at Colusa. Advanced long-grain line 14Y1006 was the highest-yielding entry at 11,380 pounds/acre averaged over three locations in 2019. Long grain L-207, short grain S-202, and medium grain premium-quality 12Y2175 yielded second, third, and fourth, respectively. Other top-yielding commercial varieties included M-105, A-202, CJ-201, M-206, and L-206.

Average number of days to 50% heading was 86. The commercial standard M-206 averaged 86 days over three locations. In the preliminary tests, M-210 was the highest yielding commercial variety, with 13 experimental lines yielding higher.

Over a five-year period and across locations, L-207 was the highest-yielding commercial variety at 10,340 pounds/acre, followed by M-209 at 9,520 pounds/acre, and M-206 at 9,410 pounds/acre.

Intermediate/late maturity tests zone 1

Ten commercial varieties and four advanced breeding lines were compared in three four-replication advanced tests. Four commercial and 10 breeding lines were compared in three two-replication advanced tests. Two-replication preliminary tests evaluated four commercial varieties and 24 preliminary lines at each location. Four advanced experimental lines and eight commercial varieties were compared in three intermediate/late tests. Preliminary tests included six commercial varieties and 18 preliminary lines evaluated in separate tests at each location. Commercial varieties at each location included S-102, S-202, CA-201, CH-201, CH-202, CM-101, CM-203, M-104, M-105, M-205, M-206, M-209, M-210, A-202, CJ-201, CT-202, L-206, and L-207.

Yields in the four-replication advanced line tests averaged 9,450 pounds/acre overall, 9,720 pounds/acre at RES, 9,090 pounds/acre at Butte, and 9,730 pounds/acre at Glenn. The 2019 advanced over-location yield decreased 450 pounds/acre (4.6%) compared to the 2018 season average. In the four-replication advanced tests, S-202 was the highest-yielding commercial variety (10,430 pounds/acre), ranking second overall. L-207 and L-206 were the next highest-yielding commercial varieties across locations. The long-grain entry 14Y1006 was the highest-yielding advanced entry across all locations at 10,700 pounds/acre.

Average number of days to 50% heading was 87. Advanced line 12Y2175 reached 50% heading at all locations in 86 days. Medium grain M-209 was the latest variety at 92 days to reach 50% heading at all locations.

Over a five-year period and across locations, L-206 is the highest-yielding commercial variety in this group at 9,490 pounds/acre, followed by M-209 at 9,370 pounds/acre.

Other activities

This project was involved in the planting, sampling, and harvesting of more than 12 trial sites throughout the rice growing areas. Educational activities such as winter rice grower meetings, the annual field day at the Rice Experiment Station, and promoting work through fact sheets, publications, and the UC Cooperative Extension rice website are also important parts of this project.