INHERITANCE OF GENE ACTION FOR YIELD COMPONENT TRAITS IN BREAD WHEAT UNDER NORMAL AND DROUGHT STRESS CONDITIONS.

Abstract

Twenty eight half diallel crosses among eight diverse parental genotypes of bread wheat were evaluated. The main objective of this study is to identify the gene action of inheritance for the yield component traits. The results demonstrated that, the mean squares of all studied traits were highly significant under normal, drought stress and combined data. The majority of cross combinations had positive significant heterosis over better parent under each environment and combined data, reflecting the prevalence of heterotic effects and non-additive effects.  Non-additive gene action (?²D) was found to play the major role in the inheritance of studied traits under each environment and their combined data. The parents P₁, P₃, P₆, P₇ and P₈ were the best general combiner for all the studied traits under the two environments and combined data. The promising crosses which showed desirable specific combining ability (SCA) effects gave also high estimate of useful heterosis.