Genetic effects and genotype × environment interactions for cooking quality traits in Indica-japonica crosses of rice (Oryza sativa L.)

Abstract

Indica-japonica hybridization is an important approach for developing superior performing hybrids in rice (Oryza sativa L.). In view of the scanty information available on cooking quality characters in indica-japonica crosses, an investigation was undertaken to estimate genetic and genotype × environment variance and covariance components of amylose content, gel consistency and alkali digestion value, and to determine the relative importance of direct genetic effects, maternal genetic effects and cytoplasmic effects in the genetic variations of the three quality characters. Two indica photo-sensitive genic male sterile (PGMS) lines and four japonica varieties were used as parents to make crosses. Genetic model with genotype × environment interactions for triploid endosperm was used for genetic studies of the three cooking quality characters. Variance component analysis revealed that genetic variations of the three characters were mainly attributable to direct additive and maternal additive effects, and the three traits had significant direct and maternal heritabilities. Genotype × environment interactions were mainly dominance × environment (including direct dominance × environment and maternal dominance × environment) and cytoplasm × environment interactions. Environment factors could only affect the expression extent of dominant genes, without changing their directions. Predicted values of genetic effects indicated that the parental lines, ‘VI-70’ and ‘H9304-1’, appeared to be best for amylose content, ‘T 1950’ and ‘Suxuan’ appeared to be best for gel consistency and alkali digestion value.