Breeding Objective

Dr. Howard L. Carnahan, director of plant breeding, explains the breeding program to station visitors. The Rice Experiment Station at Biggs is operated by the California Cooperative Rice Research Foundation, Inc and is responsible for the rice breeding program. The station cooperates with the UC Agricultural Experiment Station and the Agricultural Research Service of the U.S. Department of Agriculture. The Rice Experiment Station also produces foundation seed for publicly developed varieties. the Foundation Seed and Plant Materials Service at UC Davis cooperates by providing field and seed inspection services to assure genetic purity and high quality seed for all varieties. Rice breeding is a continuous program for developing improved rice varieties of all market types for the California rice industry.

• Improve the yields and quality of short-, medium- and long-grain rices as well as some specialty rices.

This general objective is achieved through more specific goals: earlier maturity; improved seedling vigor; resistance to diseases, insect pests, lodging and floret blanking; greater tolerance to herbicides; and improved grain translucency and head rice yields. Potential varieties also are screened for cooking characteristics and several chemical reactions that help distinguish cooking properties. The USDA-ARS Rice Quality Laboratory at the Texas A and M University Rice Research Station conducts many grain quality tests for the breeding program. In addition to the primary objectives, attention is given to selecting for minimum awning; good tillering ability; erect, stiff, green leaves; good panicle exsertion; and uniform maturity among tillers and within panicles.

All rice varieties developed by the Rice Experiment Station that are currently in production have been released since 1977. M7 and M9, released in 1977, have been dropped from foundation seed production. These varieties have rapidly disappeared in favor of new, earlier maturing varieties. Varieties released since 1979 provide growers with choices among short-, medium- and long-grain varieties, two sweet rice varieties, and a new specialty aromatic long-grain rice currently under increase.

The 10 varieties released from this program that are now in production provide growers with marketing flexibility and greater varietal adaptation for specific growing regions.

The Rice Experiment Station foundation seed program, which operates cooperatively with the Foundation Seed and Plant Materials Service and California Crop Improvement Association, makes possible rapid seed increase and availability of improved varieties (Figure 2).

M-202, released in 1986, was popular this past year. It performed exceptionally well in both cool and warmer areas. M202 replaces M9 in cool growing areas. It is not a replacement for but will compete with M-201 which is widely grown but is somewhat susceptible to blanking in cool areas. M-202 is three days earlier and ripens more uniformly than M-201, but it lodges and is not as resistant to stem rot.

 

Figure 2. Acres of foundation, registered, and certified seed of major rice varieties approved in 1986.

A new very early to early medium grain variety, M-102, was approved for release in 1987. M-102 yielded considerably more than M-101 in all regional yield trials except in a late-seeded San Joaquin County trial (a cool area). For this reason, M-102 may not completely replace M101 in cool areas. M-102 may be used where an early harvest is desired prior to flooding for duck hunting and for later than normal planting dates in warm areas.

Paddy and milled rice from the new very early medium-grain variety M-102. Yields of M-102 are superior to M-101 in all but the coolest growing areas.

M-102 also may be more desirable than M-202 in some warm areas because it has greater straw strength and more resistance to stem rot. M-202 ripens more uniformly on the head than does M-102. Cooking characteristics on M-102 are similar to those of current California medium-grain varieties.

A-301 is a new aromatic short-stature long-grain variety released in 1987. It will be grown only on a very limited acreage, and growers will want to be certain of a market before growing it. A-301 has intermediate maturity, excellent straw strength, glabrous leaves and hulls and variable awning. Milled kernels are translucent, non-glutinous and have an aromatic endosperm that smells like popcorn when cooking.

A-301 is considered to be an interim variety to permit market development of a scented California rice. Growers of A301 should have a contract before planting and take caution to prevent co-mingling of A-301 with other varieties. Other superior aromatic varieties are in various stages of development.

Other new varieties are on the horizon. They include a very early short-grain variety with superior yields; an early premium-quality, medium grain variety; and a very early, pubescent, awnless, short-stature, long-grain variety. These potential varieties are in the final stages of statewide yield trials. The very early translucent short-grain variety with the experimental designation 85-Y-136 was included in the foundation seed increase program in 1986. About 500 cwt of foundation seed was produced and distributed to seed growers in 1987 under the designation "certification pending continued good performance."

M-10Q is classed as very early but heads five days later than M-101 and two days earlier than M-QOQ. It is, therefore, borderline between the very early and early maturity groups. M-10Q has good seedling vigor and is slightly taller than M-101. It is also more resistant to stem rot and much more resistant to lodging. Kernels of M-1 02 are translucent, and its cooking characteristics are similar to other California medium-grain varieties. Foundation seed and registered seed of M-1 02 are now available. M-1 02 seed was distributed and increased by seed growers in 1986 as 84-Y-149 "certification pending."