PROGRESS REPORT FROM RICE EXPERIMENT STATION BREEDERS

Highlights

• M5 increased for release
• S6 released
• Long grain experimental promising
• Short stature rices on the way
• Very early maturing rices promising
• Excess nitrogen also reduces yields of short stature rices
• Developing higher protein rices -- a ray of hope
• Characteristics of Current Calif. rice varieties (Table 1)

Continued progress was made in 1974 in developing rice varieties for California with higher yield potential, reduced lodging and other desirable characteristics. The improved resistance to lodging of the short stature experimentals was dramatic in every test conducted throughout the rice growing areas in cooperation with U.C. Cooperative Extension. Within each maturity group numerous experimentals yielded more than our present varieties.

The use of certain parents in crosses and subsequent heavy selection pressure for seed appearance has resulted in improved seed translucency in several promising short stature experimentals.

Every effort is being made to proceed as rapidly as possible in developing improved varieties and making them available to our industry.

 

All potential new rice varieties are intensively field tested by Cooperative Extension workers and cooperating farmers before release for commercial use. Looking over a Yuba County test (right to left), USDA's Dr. J. Neil Rutger, Area Rice Farm Advisor Jack Williams, Extension Technologist Karl H. Ingebretsen and Rice Experiment Station Director M. D. Morse and guest.

þ M5 INCREASED FOR RELEASE

This medium grain is like CS-M3 in all respects except that it averages 10 days earlier in heading. Registered seed was produced on 377 acres in 1974, enough to meet the needs of producers of seed and` to allow some commercial plantings in 1975.

þ S6 RELEASED

This pearl variety has Colusa maturity, averages 13% higher yield, lodges less and has smooth hulls and leaves. Foundation seed was produced on 40 acres for distribution to seed growers in 1975.

LONG GRAIN EXPERIMENTAL PROMISING

The long grain 72/3764 again yielded more than' our current varieties in statewide tests. It has good seedling vigor, stands well and has large seeds. Seed supply will be increased for commercial quality evaluations and possible release.

SHORT STATURE RICES ON THE WAY

An experimental pearl, 74-#42, has Colusa maturity, short plant height, does not lodge, yields more than our present varieties and is practically free of white belly. Possible disadvantages are that its weight per 1000 seeds is about 10% less than Colusa, it will require slightly shallower water than Colusa, and there is variability in maturity among seeds within the panicle. It has rough hulls and leaves. Seed is available for planting about 20 acres in 1975.

 

þ Rough-hulled Calrose (left) vs. smooth-hulled CSM3 (right). Smoothness is being bred into some of the new California varieties because this hull characteristic makes the grain less abrasive on equipment and reduces air pollution in harvesting, drying and milling operations. Seeds of smooth varieties pack closer together (about 10-15 percent denser per unit volume) than rough-hulled varieties and require about 25-30 percent more static air pressure for effective drying.

An experimental medium grain, 74-#52, is of Earlirose maturity, has short plant height, is resistant to lodging, yielded more than Earlirose in this first year of statewide testing, has seedling vigor comparable to that of our present tall varieties and has larger seeds that are virtually free of white belly. Seed is available to plant 1 or 2 acres in 1975.

VERY EARLY MATURING RICES PROMISING

Seventy-nine of 81 tall, very early maturing experimental varieties yielded higher in three tests than the only commercially available very early variety, Maxwell. One experimental averaged 24.8 cwts per acre more than Maxwell. Two of the best will be grown in 1975 on 1/2 - 1 acre increase fields.

EXCESS NITROGEN ALSO REDUCES YIELDS OF SHORT STATURE RICES

Thirty-three short stature rices and two tall California varieties were seeded on May 12 at Biggs with two rates of pre-plant nitrogen fertilization -130 and 180 pounds of N per acre. Thirty of the 35 varieties yielded less at the high nitrogen rate with an average reduction of a cwt per acre. Neither lodging nor delayed maturity was a factor in this yield reduction.

DEVELOPING HIGHER PROTEIN RICES - A RAY OF HOPE

Protein content of the brown rice of 1235 short stature rices varied among lines from 5.1 to 10.0% as compared to 8.1% for Colusa. Eighty-six of the 1235 rices contained 8.3% protein or more. Basic studies are in progress to establish the reliability and value of these selections in the breeding of high protein rices.

 

Table 1 Characteristics of California Rice Varieties*
Variety/ Maturity	Grain Type1	Hull Type2	Awns	Height cm	Straw strength3	Days to 50% Heading	Owner- ship	Certified
Very Early
Maxwell	S	R	No	110	W	75	Private	Yes
Early
Earlirose	M	R	Awnlet	112	W-M	89	Private	Yes
Colusa	S	R	No	104	W-M	93	Public	Yes
S6	S	S	No	112	M	93	Public	Yes
Midseason
M5	M	S	No	112	M	101	Public	Yes
Late
CS-S4	S	S	No	116	W-M	116	Public	Yes
Caloro	S	R	Yes	116	W	117	Public	Yes
CS-M3	M	S	No	116+	M	115	Public	Yes
Calrose	M	R	Awnlet	116	M	117	Public	Yes
Terso	M	S	No	116	W	116	Private	Yes
Sweet Rice	S	R	Awnlet	101	W	120	Private	No
1 - S = Short, M = Medium     2 - R = Rough (hairy), S = Smooth (hairless)     3 - W = Weak, M = Medium
* From CALIFORNIA RICE VARIETIES: CHARACTERISTICS, PERFORMANCE AND USE. February 1975, by J. F. Williams, U. C. Area Rice Farm Advisor, Sutter Co., Yuba City, California. Late maturing varieties are day length sensitive and, when seeded late, will require fewer days to head than shown. Heading of all varieties may be delayed as much as 10 days in the coldest rice growing districts.