Rice Breeding Program-69



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Project Leader and Principal Investigators

Technical Staff:

Morton D. Morse, Superintendent

Howard L. Carnahan, Director of Plant Breeding

Johan J. Mastenbroek, Plant Breeder

Plant Breeding Assistants:

Wayne A. Van Gilder,

John W. Honan,

Norman D. Woolery

Field Operations Personnel:

Alvin P. Glover,

John M. Custer,

Clayton E. Heinaman


Virginia Belyea


During the past Fall and Spring, your Rice Experiment Station at Biggs has been concentrating on its major responsibility: developing new rice varieties through an accelerated plant breeding program.

The financial position of California rice growers can be greatly improved by the breeding of varieties with the following improved characteristics:

  • Increased yields
  • Reduced lodging
  • Improved quality and appearance
  • Increased seedling vigor
  • Development of long-grain varieties

Efforts are also being made to develop:

  • Hybrid rice
  • Stem rot resistance
  • Water weevil resistance

Every effort is being made to develop an excellent variety in the shortest possible time. Initial cross breeding is done in the greenhouse--often during the winter months. We have built an inexpensive "dark roam where valuable plants are exposed to 8 hours of light daily to shorten the daylight period and induce early heading. This procedure produces seed in the shortest possible time, accelerating our program. Other acceleration techniques include year-round use of the greenhouses and the production of a winter crop in Hawaii.

Since September, 1969, ten times as many crosses have been made as the station average for a similar period.

The Station's plant breeding personnel have made 170 separate crosses and back-crosses involving current California varieties, selected, lines, and rice varieties carrying specific desired characteristics.

Crosses are the first step toward developing a new variety. The seed from these crosses is now being grown in the greenhouse. Each cross will provide seed for 2,000 to 10,000 plants approx. total 1,000,000 plants), which will be grown in the field next year. Plants having the desirable characteristics will be selected for further evaluation

Selected parent plants are crossed to produce improved varieties

The increased number of crosses was feasible because the expanded program provides the required labor and skill to carry these crosses through generations of selections to the stage of varietal development. The crosses are required to bring together the characteristics outlined below as objectives of the breeding program.

In the spring of 1970, more than 15,000 additional rices were planted--varieties from every rice-producing nation in the world.

Elaborating on the foregoing introduction s the following information, on specific projects toward higher yields and other improved characteristics.

A short, non-lodging plant (center). The results of crossing a short variety with a tall California variety.

LODGING RESISTANCE--Several thousand selections from crosses between California and short-statured varieties are currently planted and under study. Many of these potential new varieties attain a height of only 18 to inches. They will find immediate use as breeding material and as a source from which to select commercial varieties.

EARLY MATURITY--From our past breeding program and from some introductions made last year, we have identified several varieties which mature three to five weeks earlier than our present varieties. These early varieties have been crossed with short-strawed lines n an attempt to develop early short-statured plants adapted to California.

GRAIN QUALITY--Special attention is being given all new varieties in regard to grain quality, including head yield translucency, kernel shape, taste, texture, and freedom from white belly

During the past year, seeds were examined from a large number of foreign varieties. Identified from these were several pearl varieties, having good translucency and very little white belly, if any. Numerous crosses are being made between these and the short-statured lines. In the F2 and succeeding generation the seed from these crosses will be examined to find those with the attractive appearance and other quality features so necessary in today's competitive market

Long grain selections being tested for yielding ability.

LONG-GRAIN VARIETIES--This program has been greatly accelerated.

Sixteen outstanding experimental lines which are sufficiently early in maturity and have excellent milling and cooking characteristics are being tested this year in advanced yield trials.

Numerous crosses and back-crosses have been made to combine short stature and other desirable features into a long-grain variety.

Increased Protein Content--Current varieties typically contain approximately 6% protein, too low for the diets of many people. It appears that rice with a higher protein content should have competitive marketing advantage. In 1968, some high-protein lines were crossed with California varieties at this station by the USDA. The first segregating generation was grown by the University of California, and we made several hundred panicle selections from these populations. The seed of each selection was prepared and sent to the USDA for protein analyses. Percent protein in these varied from about 5.5% to more than 12%.

Selections possessing the highest protein have been planted for further selection and to use as parents in crosses with short-statured lines of short, medium, and long grains.

SEEDLING VIGOR--Selecting for good seedling vigor is routine objective for which all breeding lines and introductions ire evaluated

RESISTANCE TO. BLANKING--Advanced experimental lines are being evaluated for their ability to tolerate low air temperatures at the time of heading without blanking. This year, 34 varieties and lines are being planted at weekly intervals. It is anticipated that one or more of these plantings will head during a period of cool nights, permitting evaluation for blanking.

OTHER CHARACTERISTICS--The smooth hull and leaf characteristic has been introduced into crosses involving pearl, medium, and long grains

Lines differ ii ease of threshing: some shatter readily and others are hard to thresh. We are striving for a happy medium.

DISEASE AND INSECT RESISTANCE--This year we are undertaking the most extensive effort made anywhere in the world to find a rice which is resistant to the rice water weevil. Nearly 10,000 rice varieties and lines have been planted primarily for this purpose. To assure a high insect population, "attraction" lights were placed over the field. Any resistant lines discovered will be used to incorporate water weevil resistance into new commercial varieties. The project is in cooperation with the Department of Entomology.

Inspecting one of 10,000 varieties for resistance to rice water weevil.

Five thousand of these varieties have been planted in pots and will be subjected to fungi of the stem-rot organism. Any lines found to carry good resistance will be utilized as parents in the breeding program. This project is in cooperation with the Department of Plant Pathology

An additional 5,000 rice introductions were planted at the Imperial Valley Field Station. After passing quarantine the seed produced will be brought to the Biggs station for further testing. Much of the seed for these tests was made available by the USDA.

HYBRID RICE--Pioneering work being done on basic problems that must be solved to make hybrid rice a commercial reality. These include field studies to determine seed set on male steriles, crosses to identify fertility restorer sources and crosses to combine the male sterile cytoplasm with desirable plant and seed type.

PROMISING EXPERIMENTAL VARIETIES Several promising lines of pearl, medium, and long-grain are the advanced stages of evaluation. Small scale seed increases are being made of several of these so that they can be made, available to growers in the shortest possible time from the date of decision to release.

To supplement our data, a number of these are being tested in county trials by, the Agricultural Extension Service.

Dr. Howard L. Carnahan joined the staff on Nov. 15, 1969 as Director of Plant Breeding.

PERSONNEL-- On November 15, Dr. Howard L. Carnahan joined the staff as Director of Plant Breeding. Dr. Carnahan brought with him enthusiasm and an excellent knowledge of modern plant breeding techniques. At the time of writing, breeding staff consists of Dr. Howard L. Carnahan, Johan J. Mastenbroek, and three assistants. For efficient exploration of the many possibilities of developing improved varieties, another plant breeder will be employed. When complete, the staff will be of sufficient size and skill to conduct a -highly productive program.

STATION FACILITIES--A new greenhouse is being built to provide sufficient space for conducting the breeding program during the winter months. An additional seed house will be built this year to provide an area for seed processing and sample storage

SERVICES AND FACILITIES PROVIDED U.C. AND USDA PERSONNEL--Thirty acres of land at the Rice Experiment Station is being used by University of California and USDA researchers. The expenses of land preparation and cultural care is paid by the Foundation from industry funds.

A new greenhouse is being constructed to accelerate the program. Rice will be grown during the winter months.

FOUNDATION SEED PRODUCTION. The production of Foundation seed is a important responsibility of the Rice Experiment Station. This program provides the industry with high quality seed which is true to variety and free from red rice.

This project is not supported by the Rice Research Act but is financed by seed sales.

CONCLUSION--We are extremely enthusiastic about the significant progress toward developing improved rices for California. We are making every effort to utilize the best available breeding methods, to expand the genetic base by planned crosses among parents with needed characteristics, to search for and identify characteristics not presently available, and to turn over the breeding cycles as rapidly as possible. We look forward to the future for California rice growers.


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