Genetic Effects ofWxAllele Combinations on Apparent Amylose Content in Tropical Hybrid Rice

Abstract

Cereal Chem. 94(5):887-891Apparent amylose content (AAC), as one of the most important quality traits of rice grain, is primarily controlled by the Wx gene, which encodes a granule-bound starch synthase. Effects of putative alleles of Wx of tropical rice hybrids generated from parents with three different nonglutinous Wx alleles (Wx a , Wx b , and Wx in ) were examined in a multienvironment trial. Genotypes of Wx b /Wx in and Wx in /Wx in were associated with intermediate AAC (20.2-23.7%), and genotype of Wx a /Wx a was associated with high AAC (24.9-28.0%). Wx alleles of Wx in /Wx in could be the most favorable combinations in selecting hybrid parents with desirable intermediate amylose content (20-25%) for rice consumers of South and Southeast Asian countries. Genotype and genotype × environment interaction were the major contributing factors to the variation in parental accessions' and hybrids' AAC, and in terms of AAC, hybrids were more sensitive than parental varieties to environment. Genotypes of Wx a /Wx a , Wx a /Wx in , and Wx in /Wx in showed higher AAC performance in the wet season than in the dry season. † Corresponding authors.