Genetic variance components and GGE interaction of tropical maize genotypes under Northern leaf blight disease infection

Abstract

Disease infection is a major destructive concern in agricultural production, thus a common point of interest in breeding procedure. Evaluation of breeding improvement on plant disease resistance greatly reveals that high yielding selection in disease-free regions indirectly improves yield in diseased environments. Forty-five F1 hybrids and their 10 parents were assessed in 2016 and 2017 cropping season across five environments using 5 × 11 alpha lattice design to: (1) estimate the genetic variance components among tropical maize hybrids under NLB disease infection, and (2) study the genotypes’ agronomic performance and stability in NLB diseased environments. Data were recorded for major agronomic traits. Highly significant mean squares were recorded for environment, genotype and genotype × environment interaction for traits under study indicating distinctiveness of the test environments. Higher proportion of specific combining ability variance over general combining ability variance across test environments shows the predominance of dominance gene effects over additive gene for the inheritance of the traits under study. Significant and positive genetic correlations recorded for the test environments indicate that the hybrids reaction across the significant and positively correlated environments was consistently related signifying similar ranking of the hybrids for NLB disease resistance across test environments. Therefore, either of the test environments would be adequate for selecting NLB disease resistance germplasm. The most stable hybrids across test environments were all derived from resistance parental lines.