Genetic Characterization of Stripe Rust and Yield Traits in Bread Wheat

The insight into the nature of gene action, involved in the expression of a trait of interest, is essential to a plant breeder for deploying a judicious breeding program. The objective of this study was to study the inheritance (additive vs., dominance) of stripe rust resistance and yield traits in wheat through diallel analysis. Six wheat cultivars i.e., Pirsabak-85, Khyber-87, Saleem2000, Pirsabak-04, Pirsabak-05 and Shahkar-13 were crossed in a half diallel fashion during 2014-2015, and advanced to F2 generation during 2015-2016. Parental genotypes along with their F1 and F2 populations were evaluated during 2016-2017 through randomized complete block design with three replications. Genotypes differed significantly (p ≤ 0.01) for all the traits in F1 and F2 generations. Additive-dominance model was partially adequate for resistance to stripe rust and yield-related traits. Greater values of additive (D) than dominance (H1, H2) components of genetic variance, average degree of dominance and VrWr graphs revealed that stripe rust resistance and yield traits were primarily controlled by additive gene action except for grain yield in F1 and area of flag leaf in the F2 generation which governed by overdominance. In loci, unequal proportions of positive (H1) and negative (H2) alleles revealed the asymmetrical distribution of genes in parental genotypes for stripe rust resistance and yield traits. The preponderance of additive gene action suggested that selection could be made in early segregating generations for improving resistance against stripe rust to enhance wheat yield. © 2019 Friends Science Publishers