Submitted to: Plant Germplasm Conservation
Publication Type: Book / Chapter
Publication Acceptance Date: 7/30/2001
Publication Date: 9/9/2002
Citation: Bockelman, H.E., Dilday, R.N., Yan, W., Wesenberg, D. Germplasm Collection, Preservation, and Utilization. Smith, C.W., Dilday, R.H., editors. John Wiley & Sons, New York, NY. Rice: origin, history, technology, and production. 2002. p. 597-625. Interpretive Summary: Rice germplasm is the raw material that breeders use to improve the rice varieties grown in the U.S. This is important because the rices presently grown are derived from a relatively few original ancestors. This can make rice production susceptible to attack by a new disease or insect problem. The USDA has been involved in rice germplasm activities since 1897 and now maintains a rice germplasm collection of over 17,000 samples. This collection is quite diverse, representing more than 110 countries and regions of the world. Not only in the U.S., but worldwide there is considerable interesting in collecting and maintaining the diversity of rices.
Technical Abstract: Maintenance of the genetic diversity of rice germplasm remains a key to genetic improvement in rice. The history of USDA rice germplasm dates back to 1897 with the establishment of the Seed and Plant Introduction Office. Up to 1948 several separate collections were maintained in the major rice producing states of Arkansas, California, Louisiana, and Texas. The rice component of the USDA-ARS National Small Grains Collection (NSGC) was officially formed in 1948 from these separate collections. Today the NSGC includes over 17,000 accessions from over 110 countries and regions, representing nine Oryza species. Components of the National Plant Germplasm System are discussed in relation to rice germplasm. Considerable emphasis has been placed on collection and maintenance of rice germplasm worldwide in recent years, with key roles played by IRRI and a number of national programs in Africa, China, India, Japan, Malaysia, Philippines, Thailand, Vietnam, and others. The importance of rice germplasm collections is illustrated by the narrowness of the genepool of U.S. rice cultivars. An examination of the pedigrees of 140 rice accessions showed that all of the germplasm can be traced to 22 plant introductions in the southern rice belt (Arkansas, Louisiana, Mississippi, Missouri, and Texas) and 23 plant introductions in the western or California rice belt.