Objective

Development of new varieties which are high yielding, resist blanking, are early maturing, have good seedling vigor, are short statured, have disease and insect resistance, and have superior grain qualities.

New varieties

Three new varieties were released in early 1979 and will be available for commercial production in 1981. Two of these varieties, M-101 and L-201, are short stature as are the earlier releases Calrose 76, M7, and M9. M-101 is a cold-tolerant, medium-grain variety that has maturity and milling characteristics similar to Earlirose. Although it may be best suited for cold locations and/or late planting, it is equally productive in warm areas. L-201 is an early-maturing, long-grain variety with very good lodging resistance and yield potential. It should not be grown in the cold areas because of cold sensitivity. Calmochi-201 is a sweet rice with maturity similar to S6.

 

This San Joaquin County experiment shows the superior lodging resistance of the new early-maturing, short-stature, medium-grain variety M-101 compared to tall Earlirose of similar maturity. All standing plots in this nitrogen fertilization experiment are M-101; the lodged plots are Earlirose. M-101 yielded an average of 1,000 pounds per acre greater than Earlirose, and milling quality of the varieties was similar.

Foundation seed of a very-earl-maturing, short-stature, medium-grain variety with cold tolerance superior to M9 will probably be released in 1980. Foundation seed for an improved short-stature pearl of S6 maturity also will likely be released in 1980. By 1981, Foundation seed for a short-stature, early-maturing sweet rice may be available.

New naming system for California rice varieties:

Representatives of the rice industry developed a new naming system for future varietal releases from the CCRRFI (Rice Experiment Station)-USDA-UC rice variety development program. Following is an outline that explains the new system:

1. Prefix Designation of Grain Type

   A. Names of long-grain rice will be preceded by the letter (L) and a dash (-), i.e. L

   B. Names of medium-grain rice will be preceded by the letter (M) and a dash (-), i.e. M

   C. Names of short-grain rice will be preceded by the letter (S) and a dash (-), i.e. S

   D. Names of sweet (waxy) rice will be preceded by the word Cal mochi and a dash (-), i.e. Calmochi

2. Four relative maturity group number series (100, 200, 300, and 400) will be assigned to each grain type (i.e. long; medium, short, and Calmochi). Within a grain type, the lower number series will indicate earliest maturity (fewest days to heading), and the higher number series will indicate progressively later maturity (more days to heading). The last two numbers in the designation will indicate order of release within grain type and maturity group. Following is an outline and example of the system:

   A. Names and designations of future varieties:

   Letter and Number Series	Maturity Group
   L-101 --- L-199	Very early
   L-201 --- L 299	Early
   L-301 --- L-399	Intermediate
   L-401 --- L-499	Late
   M-101 --- M-199	Very early
   M-201 --- M-299	Early
   M-301 --- M-399	Intermediate
   M-401 --- M-499	Late
   S-101 --- S-199	Very early
   S-201 --- S-299	Early
   S-301 --- S-399	Intermediate
   S-401 --- S-499	Late
   Calmochi-101 --- Calmochi-199	Very early
   Calmochi-201 --- Calmochi-299	Early
   Calmochi-301 --- Calmochi-399	Intermediate
   Calmochi-401 --- Calmochi-499	Late

   B. Examples of three new varieties released in 1979 and named by this system and a potential release for 1980 include:

   1. L-201: Long-grain variety (L) of early maturity (200), and first release (1) within this grain type and maturity group. Released in 1979.
   2. M-101: Medium-grain variety (M) of very early maturity (100), and first release (1) within this grain type and maturity group. Released in 1979.
   3. M-301: Medium-grain variety (M) of intermediate maturity (300), and first release (1) within this grain type and maturity group. Released in 1979 (pending).
   4. S-201: Short-grain variety (S) of early maturity (200), and first release (1) within this grain type. A new variety is planned for release in this group in 1980.
   5. Calmochi-201: A special sweet (waxy) rice variety of early maturity, and first release (1) within this specialty type. Released in 1979.

This naming system should be valuable to the industry in variety selection, harvesting, storage, and milling. The grain type designations should prevent mixing of different grain types, and the maturity designation should prevent too early and/or too late seeding for specific varieties. Growers are encouraged to become familiar with the system.

Better yields

Improved yields are the primary economic advantage offered by new varieties and have been a major objective of the breeding program. Seventy-two potential varieties were tested in California's major rice-growing areas in 1978. Results of these tests indicate a high degree of success in achieving better yields.

The statewide test of early-maturity lines contained two tall commercial varieties and one tall experimental. The 21 entries having short stature or intermediate height yielded more than the three tall lines. Nine entries including five "short-stature S6 types" gave average yields higher than M9 but not significantly higher.

In the statewide trial of 24 late-maturity lines, the two tall commercial check varieties ranked 22nd and 24th in yields. Calrose 76 and M7 averaged 600 to 1,000 pounds per acre more than the tall varieties, and a short-stature version of M5 yielded nearly 1,000 pounds per acre more than M5.

Additional high-yielding materials have been identified in preliminary yield trials and will be fed into the statewide testing program in 1979.

Desirable characteristics

Specific traits that influence the breeding program and the progress being made include:

Lodging resistance. In addition to intense selection among shortstature lines, additional crosses are being made to introduce better straw quality and to evaluate the feasibility of double dwarfs.

Early maturity. Crosses have been obtained that represent a complete range in heading, from 10 days earlier than Earlirose to as late as Calrose.

Quality. Seed appearance - size, translucency, shape, uniformity, and breakage - is the basis for making about 40,000 varietal selections each year from 150,000 to 200,000 possibilities. This selection has been highly effective, but there is still considerable room for further development of translucent, larger-seeded forms of each grain type. Chemical and cooking quality tests are performed on all varieties before release. Additionally, millers are provided samples for their evaluation before release for commercial production.

Long grain. Much of the California long-grain germplasm now has yielding ability comparable to short- and medium-grain varieties in the warmer rice growing areas of the state. The area of adaptation is being widened with each cycle of breeding. One early-maturity, long-grain variety (L-201) has given yields comparable to those of M9 in two years of statewide testing.

Extensive cooking evaluations of long-grain materials suggest that cooking quality problems can be overcome, but these problems are very complex.

Sweet rice. Foundation seed of Calmochi-201, a short-grain, sweet rice that resembles S6 was released in 1979. It yields slightly less than S6 and has a little higher moisture at harvest. Because it is earlier than other California commercial sweet rice varieties, it may serve an intermediate role until a short-stature, short-grain, sweet rice becomes available.

Tolerance to low temperature. Several short-stature pearls similar in maturity to S6, but with superior tolerance to blanking, have been identified and are currently being tested throughout the state.

Tolerance to rice water weevil. Progress in this area is slow because of apparent low heritability of this trait. Materials with clear-cut resistance are not currently available.

Herbicide tolerance. All experimental lines are screened for susceptibility to Ordram and MCPA to assure that new varieties have the same or greater tolerance as existing varieties to these herbicides.

Seedling vigor. Excellent progress is being made in improving the seedling vigor of short-stature rice to improve stand establishment, weed control, performance and yields.

Improvements in many of these areas will be evident in future varietal releases. The result will be higher and more stable yields and improved grain quality.,