California Medium Grain Varieties

DR TERESA B. DE LEON / CALIFORNIA COOPERATIVE RICE RESEARCH FOUNDATION, INC.

Rice growers know that rice productivity varies year after year due to environmental challenges. However, not all varieties are equal, some varieties consistently performed better in specific locations. Therefore, we highly encourage rice growers to check the University of California Cooperative Extension variety trials at https://agronomy-rice.ucdavis.edu/ for more information about California rice varieties and management.

Currently, there are seven medium grains available for rice growers. However, due to very mate maturity, the premium quality M-401 has limited acreage. Likewise, the herbicide-resistant Roxy rice M-521 is only grown for research with pending EPA chemical registration. Consequently, there are only five medium grains that mainly occupy the rice acreages of California. These are the early maturing M-105, the widely grown M-206, lodging-resistant M-209, blast-resistant M-210, and the high yielding M-211.

While M-211 (teal diamond) has been the highest yielding variety in North Butte, RES, Glenn, and Yolo for the past five years (Figure 1), it also exhibits the lowest milling yield when harvested at moisture content lower than 18% (Figure 2). In contrast, genetically related medium grains such as the M-105 (orange triangle), M-206 (green triangle), and M-210 (purple triangle) performed well in Yuba, South Butte, Sutter, Yolo, and San Joquin (Figure 1). Additionally, M-105, M-206, and M-210 are excellent millers with low percentage of chalky grains (Figure 2). On the other hand, lodging-resistant M-209 performed best in Colusa with better milling yield than M-211.

This year, we are releasing the M-212 rice variety (aka 18Y3018) that carries desirable alleles for Pi-b and Pi-z blast resistance genes. Overall, M-212 is equally high yielding as M-211 and offers a 4% yield advantage over M-210. It has high seedling vigor, and it flowers at 90 days, which is four days later than M-210 but two days earlier than M-211. M-212 showed lower lodging potential than M-210 and M-211. Furthermore, M-212 has excellent milling yield and low percentage of chalky kernels like M-210. With pedigree that traces back to M-210 and M-206, M-212 is an excellent alternative variety especially in areas where blast disease was observed. Here’s a look at the variety performance of M-212 by location in the statewide UCCE variety trials from 2019-2025 (Table 1).    ∆

DR TERESA B. DE LEON / CALIFORNIA COOPERATIVE RICE RESEARCH FOUNDATION, INC.

Figure 1. Five-year average yield of medium grains by location in the UCCE statewide variety tests.

Figure 2. Milling yield trend of medium grains (RES, 2025).

Table 1. Overall grain yield by location of M-212 (18Y3018), M-210, and M-211 in the UCCE statewide variety trials from 2019-2015.

DR TERESA B. DE LEON / CALIFORNIA COOPERATIVE RICE RESEARCH FOUNDATION, INC.