BRUCE LINQUIST / UNIVERSITY OF CALIFORNIA, DAVIS
In California, most acreage is devoted to high quality, medium-grain varieties. Details of our 2025 varietal testing can be seen on our website at https://agronomy-rice.ucdavis.edu/. For this discussion and ease of interpretation, I will only discuss medium-grain varieties and divide up the nine variety trial locations into two broad environments: those with warm nights and those with cooler nights in July. 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 Highway 20.
In the warmer region north of Highway 20, M-211 is historically the best-yielding variety. The five-year average for M-211 is 92 cwt/acre and is closely followed by M-209 (90 cwt/acre). Interestingly, M-105 and M-206 are the lowest yielding (84-85 cwt/acre), while the blast-resistant M-210 has averaged 88 cwt/acre. In the cooler regions south of Highway 20, historically M-206 has done very well, and the five-year average is 95 cwt/acre. M-105, M-210, and M-211 have also performed well in this region with five-year averages at 92-93 cwt/acre. M-209 performs the poorest and has averaged less than 90 cwt. In 2025, we had a new location near Winters. This is maybe the coolest variety trial location. At this site, both M-206 and M-210 did very well and averaged over 102 cwt/acre.
In 2025, we ran a nitrogen X variety trail at two locations (RES and Arbuckle). The trail had six nitrogen rates and nine varieties. Just talking about the medium grains in the trial, M-211 had the highest yields at both locations. M-209 had similar yields to M-211 at the RES, while M-105 yields in Arbuckle were similar to M-211. Despite differences in yield potential, they all required a similar nitrogen rate to achieve the yield potential. In terms of lodging, M-105 was most susceptible to lodging, followed by M-206 and M-210. M-211 and M-209 had very limited lodging, even at excess nitrogen levels.
Thinking about variety selection for 2026, M-211 is popular 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 with 2026 being the last year for foundation seed sales. M-209 is a good replacement for M-211 in the northern part of the valley. 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. ∆
BRUCE LINQUIST / UNIVERSITY OF CALIFORNIA, DAVIS