Submitted to: Experiment Station Bulletins
Publication Type: Experiment Station
Publication Acceptance Date: 12/21/2000
Publication Date: N/A
Technical Abstract: Rice end-use quality is strongly impacted by its amylose content (AC). The amount of this starch fraction is primarily controlled by the Waxy gene (Wx). A rapid method for evaluating a microsatellite associated with the Wx gene (Wx marker) has been developed and its efficacy tested using the 1999 Uniform Regional Rice Nursery (URRN) entries and an independent breeding population. The variation in AC content for the URRN entries which was explained by the microsatellite was 88 percent. This indicates that a strong relationship between AC and the Wx marker holds across the divergent genetic backgrounds found currently in U.S. breeding programs. A population developed from a cross between Dellmont (Conventional long grain type) and B8462T3-710 (Superior processing type) was examined. Clear differences in the progeny which had similar AC content but different processing quality were easily discerned using the Wx marker. Traditionally, AC content has been the only data breeders had to select lines with superior processing quality during early breeding generations. This data would then have to be verified in later generations when more seed was available using the RVA, a more time consuming laboratory method. The results of this project demonstrate the ability of marker assisted selection to decrease varietal development time by improving the accuracy of selections by breeders and allowing this selection to take place even when just single plants are available. This rapid method is now a routine component of the USDA ARS Rice Quality Evaluation Program, Beaumont TX.