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United States Department of Agriculture

Agricultural Research Service

Current Research Objectives of the Rice Varietal Improvement Program
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1.  Development of new rice varieties for production in the Southern U.S. These cultivars will be improved for production traits like yield potential, disease resistance, lodging resistance, maturity, second crop potential, and tolerance to insect pressure. They will also have high milling quality and specific cooking and processing characteristics as required by the rice industry.

a.    Conventional rices. Most of the breeding effort is directed towards conventional long grain rices which predominate in the southern rice belt. These cultivars are used by the white milled rice industry and have grain characteristics which result in the rice to cooking dry and flaky (not sticky). An example of a new release from this research program is Saber. This cultivar was derived from a cross of Gulfmont, a commercially important long grain variety developed by this program in 1986, Teqing, a high yielding cultivar from China, and RU8703196, a germplasm that has good resistance to the diseases blast and sheath blight. Saber is an early maturing semidwarf that has broad spectrum resistance to all of the races of blast that currently occur in the U.S. It also has improved resistance to sheath blight. It has good yield potential and superior milling quality.

b.    Specialty rices. Rices developed for the specific needs of niche markets usually command a premium market price. This added-value benefits the rice producer. Although these specialty rices may not be grown on large acreage, there is an increasing demand in the market place for rices having novel cooking, flavor, processing, and appearance characteristics. Research is being conducted to develop cultivars that meet various niche market needs so that U.S. rice producers can compete in all market arenas. Several specialty rices have recently been released from this program.

Bolivar - a long grain cultivar having superior processing and parboiling characteristics that are desired by the parboiling and canning industries.

Sierra - a long grain cultivar that is scented like popcorn and the grains elongate during cooking like imported basmati rice.

Lavaca - a long grain cultivar that has greater than normal volume when cooked.

Lotus - a popcorn-scented long grain cultivar

Neches - a glutinous (waxy) long grain cultivar that could be used by the rice starch and rice flour ingredients industry instead of imported waxy rice.

2.   Development of new breeding methods. It takes 7 to 10 years to develop a new cultivar using conventional methods. Development of improved breeding techniques expedite the breeding process and shorten the delivery time of new cultivars to rice producers. A major thrust of the breeding program over the last few years, has been the development of molecular markers that can be used in marker assisted selection. Molecular markers are pieces of the rice genetic code that are associated with traits important in rice cultivars. Breeders usually select for traits that are observed under field conditions. However, these traits can be skewed depending on the influence of the field season and growing conditions. The presence or absence of genetic markers is stable regardless of the environment that the breeding lines are grown in. Thus, a strong association of a marker with a trait will allow the breeder to more effectively select for the trait regardless of the environmental conditions. Over the last few years we have made significant progress in developing genetic markers associated with blast resistance genes, cooking quality, and processing quality. Markers were used to produce the cultivars Cadet and Jacinto and resulted in decreasing their development time by several years. We are continuing research in this area to increase the number of traits that are associated with genetic markers and can be used in applied breeding programs.

3.   Evaluation and utilization of naturally occurring genetic resources of rice. There is a tremendous amount of naturally occurring genetic variability that is available in the world's rice germplasm. We continue to evaluate germplasm from other countries and from other related species to determine if there are traits that could be used in the development of new rice cultivars. We have already been successful in incorporating a new gene (Pi-b) from Chinese germplasm that provides resistance to some of the races of blast disease that is caused by Pyricularia grisea We have also identified another novel blast resistance gene in a related weed species of rice. Research is continuing to identify germplasm that possesses unique genes for yield and processing quality as well as response to production under organic culture.

Last Modified: 2/23/2005