Considerations for choosing the right medium grain rice variety

                        With planting season coming up, thinking about appropriate variety selection is key, and one of the first steps towards ensuring a good 2021 crop. Each year the California Rice Research Board funds a statewide variety trial testing program. Here I summarize some of that data.

These trails are on grower managed fields in eight locations around the Sacramento Valley as seen in the map. One major difference in the locations selected is nighttime temperatures in mid to late July when most of the rice is booting. Cold temperatures during this period can cause blanking and lower yields. On the map, locations in red are where cold nighttime temperatures are usually not a problem. These locations are generally north of highway 20. In yellow are locations where growers need to be concerned about low nighttime temperatures; while they may not occur every year, they are common. In blue (South Yolo) is a location where cold temperatures occur almost every year. Importantly, in each of these regions may be micro-climates where temperatures vary from the “average”.

Some varieties are more tolerant of cold than others. Therefore, it is important to select varieties that are suitable for the location you are farming. In the tables below, are yield data from the past five years for each location in the variety trial. Only the main medium grains varieties are shown (M-105, M-206, M-209, M-210 and M-211). This data will allow for a more informed decision when it comes to variety selection.

The warmer locations are north of Hwy 20,in Glenn, Butte and Colusa counties. At these locations, M-211 consistently outperforms the other medium grains by 4 cwt/ac, on average, over the five years and four locations. Among the other varieties shown, there were no consistent differences among them.

In the cooler locations, M-209 performed the worst in general. In the moderately cool locations (yellow dots on the map), M-105 and M-211 both did consistently well. In the coldest location (South Yolo), M 105 performed the best; while M-209 and M-211 performed poorly. Both M-209 and M-211 have similar days to maturity (about 5-7 days later than M-206). This data suggest that M-211 may have a broader adaptability range than M-209 becasue it appears to be slightly more cold tolerant. However, in the coolest location even M-211 did not perform well.

M-206 versus M-210: M-206 has beenthe most broadly adaptable variety available. While it may not always be the highest yielder, it generally does well across all locations. M-210 is a new variety which has blast resistance. It is basically M-206 with genes for blast resistance and has similar time to heading. Based on these data M-206 and M-210 have almost identical yields in both the warm and cooler regions.

Thoughts on M-211: As seen in the data provided, M-211 is a tremendously promising variety in terms of yield potential. Furthermore, its sensory qualities are similar to premium grain varieties such as M-401. However, one draw back is that for good milling quality, M-211 needs to be harvested at 20-22% moisture. Harvesting below this moisture can result in low milling quality. Given this, it may not be a variety that is suitable for large acreage planting and this should be tested by growers.