Grain yield and stability of tropical maize hybrids developed from elite cultivars in contrasting environments under a rainforest agro-ecology

Abstract

In the maize producing regions of Sub-Saharan Africa (SSA), compounding effects of genotype-by-environment interaction have necessitated breeding maize for outstanding performance and stability across varying environments. This study was conducted to assess the performance and stability of late-maturing cultivars and their respective hybrids evaluated under contrasting environments in the tropical rainforest region. We evaluated 108 genotypes in field trials under three different growing conditions in 2018 involving 14 open-pollinated parents and their hybrids derived from a diallel mating design. The genotypes were evaluated under field conditions using 9 × 12 alpha lattice design with three replications in six environments. The genotypes were divided into three groups, containing either the parents, hybrids or checks, for estimating the stability variance and grain yield. The difference between the lowest and highest yielding environment was 3.9 t ha−1, while the repeatability of the grain yield trials ranged from 39 to 80%. The average grain yield of the hybrids (2.33 t ha−1) was significantly higher than that of the parents (2.19 t ha−1) and the check varieties (2.03 t ha−1). The hybrids were more stable than both the parents and the checks. They also showed a higher stability against a common group of the parents and checks. The results of this study suggest that high yielding and stable population hybrids can be utilized in breeding programmes aiming to provide improved varieties for the large number of rural maize farmers in the SSA zone, who often lack access or the capacity to purchase commercial hybrids.