Submitted to: Experiment Station Bulletins
Publication Type: Other
Publication Acceptance Date: June 20, 2003
Publication Date: July 1, 2003
Citation: PINSON, S.R. TRACKING AND TAMING RICE GENES: HOW RESEARCH GENETICISTS ASSIST PLANT BREEDERS. EXPERIMENT STATION BULLETINS. 2003. 3 pp.
The beneficial impact of improved varieties, and thus of the plant breeders who develop them, on the U.S. rice industry is directly felt and much talked about by producers, millers, and processors. Benefits gained from basic genetics research are less direct and more difficult for the rice industry to identify and understand. USDA Research Geneticists produce germplasm and genetic information that improve the breeder's ability to create desired rice varieties. For example, if a trait is desired but not present among U.S. rice varieties, then geneticists look through rice varieties from around the world, identifying ones that do contain the desired trait/genes. After a line expressing the desired trait is identified, geneticists study the genes responsible for that trait by observing how the trait is passed from parents to offspring within a study population. When multiple genes affect a trait, it is very difficult for breeders to find and maneuver them all into an improved variety. Similar to predicting a wild animal's location by tracking its food sources and footprints, geneticists find genes by observing their genetic environment. Once genes are found, they can be "tagged" with DNA markers, allowing them to be reliably tracked by breeders as they "roam" among breeding lines. If the desired genes are only found in wild relatives of rice where they are mingled with many undesirable genes, then it is difficult for breeders to incorporate them into improved varieties even if the desired genes are molecularly tagged. Geneticists work to "tame" genes by separating them from the undesirable wild genes and incorporating them into otherwise domesticated genetic backgrounds, making them more accessible to breeders. Dr. Pinson, a USDA Geneticist studying rice, has identified genes for several traits including disease resistance, plant height, heading time, and several traits known to affect yield. She has "tamed" genes for blast resistance and seedling vigor, and is presently tracking genes for rice grain quality and improved tiller production.