Hybrid performance and heterosis in early segregant populations of Brazilian spring wheat.

Abstract

The objective of this study was to estimate the inbreeding depression and heterosis relative to the mid-parent and better parent for grain yield and yield components in a set of diallel crosses involving 10 wheat genotypes. Parents and F1 and F2 hybrids were evaluated under field conditions using a spaced plant scheme in a randomized block design with three replications. The heterosis, heterobeltiosis and inbreeding depression for agronomic traits were calculated. There was a negative correlation between the heterobeltiosis and grain yield per plant (GYP) inbreeding depression, indicating the presence of positive additive additive epistatic interactions. The mean GYP values for the F1 and F2 progenies were 20 and 10% higher, respectively, compared with the parents, indicating that the hybrids were superior to the parents. The heterosis of the number of spikes per plant in the F1 and F2 generations can be a useful approach for the indirect selection of wheat plants with an improved grain weight and grain yield per plant. The study reveals good scope for isolation of pure lines from the progenies of heterotic F1's as well as commercial exploitation of heterosis in spring wheat.