Generation mean analysis for some heat tolerance and quantitative characters in bread wheat (Triticum aestivum L.)

Abstract

Genetic analyses were performed for heat tolerance parameters viz. heat injury and chlorophyll stability index,grain protein content, grain yield and its components in bread wheat. Three crosses namely Raj 3765 x PBW 343, Raj 3765 x Raj 4037 and Raj 3765 x Raj 4083 of four parents were used for genetic analyses. The mean days to maturity were depicted as 112.59, 1000 grain weight (38.39 g) and grain yield (16.14 g), respectively. General means for grain protein content, heat injury and chlorophyll stability index were exhibited as 12.58, 44.02 and 14.32 per cents, respectively. A, B, C and D scaling tests revealed that additive-dominance model was inadequate for all the three crosses for days to maturity, two crosses for days to heading, and one cross for grain protein content, which indicated presence of non-allelic interactions. However, all the three crosses showed adequacyof additive-dominance model for grain yield and its components. Among digenic interaction dominance x dominance (l) and additive x additive (i) were more important as compared to additive x dominance (j) for most of the characters. Duplicate type of epistasis was exhibited for days to maturity in two crosses viz. Raj 3765 x PBW 343 and Raj 3765 x Raj 4037, while for grain protein content in one cross Raj 3765 x Raj 4037.