The California Rice Research Board supports our statewide variety trail evaluation each year. This project runs nine variety trails around the state and evaluates commercially available lines as well as promising lines that are coming out of the Rice Experiment Station. These are large trails with each one having over 140 plots. These trails are conducted in farmer’s fields under their management practices. It can be a bit of a challenge for them, and we thank them for allowing us to work in their fields.
I am presenting a summary of results here. Details can be seen on our website at https://agronomy-rice.ucdavis.edu/. For ease of interpretation, I divide up the nine locations into two broad environments: those with warm nights and those with cooler nights. Cool nighttime temperatures in mid to late July when the rice is booting can cause sterility and result in blanking of grains. Cool nights are more common south of HWY 20.
In the warmer region north of HWY 20, M-211 is historically the best yielding variety. The 5-year average for M 211 is 92 cwt/ac. This is closely followed by M-209 (90 cwt/ac). Interestingly, M-105 and M-206 are the lowest yielding (84-85 cwt/ac), while the blast resistant M-210 has averaged 88 cwt/ac. In 2025, high yielding varieties at given locations included M-211(RES), M-209 (Colusa) and M-105 (Butte, Glenn).
In the cooler regions south of HWY 20, historically M-206 has done very well, and the 5-year average is 95 cwt/ac. M-105, M-210 and M-211 have also performed well in this region, 5-year averages at 92-93 cwt/ac. M 209 tends to do poorest and has averaged less than 90 cwt. In 2025, we saw generally similar results. We had a new location this year near Winters. This is maybe the coolest location. At this site, M-206 and M-210 did very well and averaged over 102 cwt/ac.
Thinking about variety selection for 2026, M-211 is a popular variety due to its high yields; however, milling can be poor when harvested at lower grain moisture. Due to poor milling stability, a number of rice driers limited the amount of M-211 accepted in 2025. This may also be the case for 2026. M-211 is being phased out and 2026 will be the last year for foundation seed sales. The RES is hopeful that they will have another higher yielding variety with better milling quality stability to replace it. M-210 and M-206 are almost identical genetically and agronomically (similar yields, lodging scores, heading dates, plant height, etc), except that M-210 carries blast resistance. Both M-210 and M-206 do well across the state, but particularly in the southern region. M-105 is the shortest duration variety and has very good yields; however, it is prone to lodging.