U.S. long grain rice. Click
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Rice Collection Identifies Valuable Traits
By Jim Core
December 13, 2004
Agricultural Research Service
scientists recently completed an agronomic analysis of an important rice
genebank, providing breeders with valuable information that they can use to
improve this vital crop.
The researchers analyzed the U.S. Department of Agriculture Rice Core
Collection, part of the National Small Grains Collection (NSGC). The rice
core collection's 1,801 entries represent about 10 percent of the 17,396 rice
accessions in the NSGC.
The ARS analysis shows that the core collection captures more than 70
percent of the genetic variation in all the NSGC lines, according to estimates.
Reaching this milestone will help researchers to find genes that have important
traits and to transfer those genes to commercial cultivars.
NSGC is part of the ARS-coordinated National Plant Germplasm System
(NPGS), a cooperative effort by
public and private organizations to preserve the genetic diversity of plants.
Accessions are included in a database so scientists worldwide can search for
specific characteristics that interest them, and can request the germplasm for
Yan, a geneticist at the ARS Dale Bumpers National Rice Research Center (DBNRRC)
in Stuttgart, Ark., leads efforts to build the core collection. He completed
the agronomic analysis in collaboration with
Tai, a rice geneticist in the ARS
Pathology and Genetics Research Unit at Davis, Calif.;
Bockelman, curator of NSGC in
Rutger, director, DBNRRC.
Last year, Yan froze leaf tissues of the core collection lines for
molecular analyses. Molecular geneticists have developed 183 Simple Sequence
Repeat (SSR) markers to locate genes that determine agronomic traits and
quality. The ARS scientists at Stuttgart have completed the SSR analysis for
300 of 1,801 entries.
ARS scientists at the
Research Unit in Beaumont, Texas, assisted by analyzing molecular markers
related to grain quality. Thanks to joint federal and state efforts, 21 out of
30 descriptors used to describe plant traits, such as aroma and pest
resistance, have been evaluated for this collection.
ARS is the USDA's chief scientific