Objective

• Evaluate experimental varieties in cooperation with public and private rice breeders for purposes of new variety development.

Experimental varieties developed through the breeding program at the Rice Experiment Station, Biggs, are tested initially as a part of the breeding program. Those showing greatest promise are turned over to UC Cooperative Extension for on-farm evaluation at various locations.

The decision to release and increase a new variety is based on all available evidence. Release is first recommended by the Board of Directors of the California Cooperative Rice Research Foundation. Final approval rests with the Board of Directors of the Crop Improvement Association, which is responsible for rice seed certification.

Statewide uniform varietal tests were organized according to three maturity groups, plus one trial of long-grain varieties and a special test of short- and medium-grain varieties. Nine uniform trials were conducted using seed provided by the Rice Experiment Station, or in the case of varieties developed by private rice breeders, seed was provided by the owner. Detailed results are made available in an Agronomy Progress Report.

Twenty-six very early varieties, those reaching 50 percent heading at Biggs in less than 90 days, were compared in three tests. The top yielding entries were Calmochi-101 and M-202, which were the check varieties. Third in rank for yield was M-102.

Early varieties, those reaching 50 percent heading between 90 and 97 days at Biggs, were tested at five locations. Twenty-three experimental and eight commercial varieties were included in these trials. One experimental variety, 85-Y-136, was the leader for yield at all locations. This is an early short-grain variety which has been approved as "certification pending." The naming, release and certification depend on continued satisfactory performance in 1987 trials. A preliminary seed increase was made in 1986.

Intermediate and late varieties are those requiring more than 105 days to 50 percent heading at Biggs. Two trials were conducted with 21 experimental varieties and three check varieties. An experimental short-grain, 83-Y-502, had the highest yields, but its future has not been decided.

The long-grain test included 23 experimental varieties and two check varieties. The leading variety in yield, 85-Y-349, yielded significantly higher than L-202. Some of the more promising entries from this test may be advanced to the statewide trials in 1987. The special short- and medium-grain test was conducted to increase the number of preliminary breeding lines in off-station locations. Several more promising lines may be advanced to statewide trials in 1987.

The yield and agronomic characteristics of standard varieties are summarized in Table 1. These varieties are included in statewide varietal trials as check varieties. Experimental varieties must equal or exceed the performance of these released ones for them to be considered as potential new varieties. Their characteristics are described in the section that follows.

Table 1. Yield and agronomic characteristics of California rice varieties as averaged over various statewide trials and years.¹

Variety	# of tests	Years	Yield	Moisture at harvest	Days to 50% heading	Plant Ht (in.)	Percent lodging	Seedling vigor2	Hull type3
S-201	20	1983-86	8830	20.9	97	36	28	4.2	S
M-201	20	1983-86	9090	21.7	95	34	9	4.0	S
M-202	20	1983-86	9590	20.5	92	36	25	4.0	S
M-302	22	1980-86	8990	19.4	103	37	20	4.2	S
M-401	22	1980-86	9180	19.5	109	37	45	4.4	S
M-7	22	1980-86	8850	20.5	112	38	12	4.4	S
M-101	13	1985-86	8620	18.3	86	36	42	4.2	S
M-102	13	1985-86	9600	20.6	91	36	8	4.3	S
Calmochi-101	13	1985-86	9670	15.2	86	35	24	4.2	P
Calif. Belle	20	1982-86	7870	16.5	89	40	34	3.7	S
L-202	20	1982-86	8810	17.7	96	32	2	3.8	S
Aromatic 301	8	1984-86	7660	16.7	113	35	27	4.1	S
1 Direct comparisons only can be made among varieties included in the same trials. These are identified in groups separated by the colored sections. However, the larger number of tests for most established varieties give a reasonable, although not direct, indication of relative performance. 2 Subjective score with 1=very poor; 5=excellent. 3 S=smooth; P=pubescent

Varietal Characteristics

Short grain

S-201. High yield potential, excellent seedling vigor, similar to M-201 in maturity and in resistance to blanking; has good pearl shape.

Medium grain

M-101. Earliest variety; excellent seedling vigor; good resistance to blanking. Yields are less than other varieties at normal planting dates. Suggested only for special conditions such as coldest areas and/or latest planting dates. To minimize reduction in head rice, which is generally low, harvest at 25 percent moisture.

M-102. Heads 5 days later than M-101, 2 days earlier than M-202; matures midway between M-101 and M-201, very high yield potential, excellent seedling vigor, good resistance to blanking, has more resistance to stem rot and to lodging than M-101 or M-202. Has more variable maturity within panicles than M-101 or M-202. Foundation and registered seed available in 1987.

M-201. Very high yield potential; 2 to 3 inches shorter than M9 with excellent resistance to lodging and more responsive to nitrogen. Threshes very easily, so reduce reel and cylinder speed to minimize shatter and enhance head rice. Has replaced M9 in warmer rice growing areas; best resistance to stem rot but susceptible to aggregate sheath spot.

M-202. Very high yield potential; replaced M9 in cooler rice growing areas where M-201 is not well adapted; three days earlier, ripens more uniformly and more resistant to blanking than M-201; lodging intermediate between M-201 and M9; threshes easily but does not shatter; not as resistant to stem rot as M-201 or M-102.

M-401. Is a premium quality rice with high yield potential. Has large bold seeds; is more sensitive to blanking, lodging and damage from early drainage than M7; therefore, use somewhat less nitrogen than on other varieties.

Long grain

L-202. Good yield potential in warmer areas; not adapted to colder areas; shortest of current varieties; excellent resistance to lodging and appears to be highly responsive to nitrogen. Seedling vigor fair; requires careful water management. Threshes easily, so use minimum cylinder speed to enhance head rice. Harvest moisture for L-202 should not be below 18 percent or above 20 percent.

Specialty rices

Calmochi-101. A sweet rice 15 days earlier than Calmochi-202; has desirable larger seed and improved cooking quality; excellent resistance to low-temperature blanking; has rough leaves and hulls; no awns.

Calmochi-202. A sweet rice similar to S-201 in growth characteristics but two days later. Has smaller seeds. Yields about 8 percent less than S-201.

A-301. An aromatic ("popcorn" aroma) long-grain with moderately high yield in warmer areas, not adapted to late seeding dates, deep water or cool areas. Suggest harvest moisture of 20 to. 22 percent and air drying without heat to retain maximum aroma. A-301 has excellent straw strength. Foundation seed available in 1987.