Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: February 1, 1996
Publication Date: N/A
Genetic factors play an important role in the control of cooking, processing, and eating qualities in long grain rice. In an effort to identify significant loci for processing quality characteristics, an F5 bulk population from a cross between the high amylose variety Rexmont, and the low amylose, low gelatinization temperature variety Toro 2 was analyzed dby the use of microsatellite DNA markers. Genotypes at loci for several enzymes involved in carbohydrate metabolism were identified and correlated with amylose content, alkali spreading value, and paste viscosity measurements. As predicted, the genotype at the waxy locus (granule bound starch synthase) was highly correlated with amylose content and accounted for approximately 86 percent of the variance. This locus was also associated with gelatinization of the starch as measured by the alkali spreading value (18 percent of the variance) and in the breakdown of paste viscosity (55 percent of the variance). The genotype at the soluble starch synthase locus accounted for approximately 42 percent of the variance in amylose content, 11 percent of the variance in the alkali spreading value, and 30 percent of the variance in the breakdown of paste viscosity. The soluble starch synthase locus is known to be closely linked to the waxy locus (5 cM), and the correlation with cooking and processing characteristics is likely due to a linkage effect. Our results indicate that a significant proportion of the variation in traits considered highly important for rice cooking quality estimation can be accounted for by the genotype at the waxy locus.