Genetic analysis in wheat (Triticum aestivum L. Em. Thell.) 

Abstract

In bread wheat ten genotypes were crossed in half diallel fashion to estimate gene action involved in the inheritance of grain yield and its component traits The non-significance of 't²' values suggested that additive-dominance model was adequate for days to 50% flowering, plant height, number of effective tillers per plant, number of spikelets per main spike, days to maturity, number of grains per main spike, grain weight per main spike, 100 grain weight, grain yield per plant, biological yield per plant, harvest index and protein content. Additive (D) and both the dominance components (H₁, H₂) were significant for all the above said characters except 'D' for days to 50% flowering, number of effective tillers per plant, length of main spike, peduncle length of main spike, grain yield per plant, harvest index, total soluble sugar and chlorophyll content. The average degree of dominance (H₁/D)^1/2 was greater than unity for all the traits indicating over dominance behavior of interacting alleles. Asymmetrical distribution of positive and negative genes in the parental lines was revealed from the estimate, H₂/4H₁ for all the characters except days to maturity and grain weight per main spike for which symmetrical distribution was evidenced. Narrow sense heritability estimates were less than so per cent for all the traits (except grain weight per main spike) indicating major role of dominance gene effect in the expression of grain yield and its component characters.