Yield potential and yield stability of maize hybrids selected for drought tolerance

Abstract

Objective: Drought and low soil nitrogen(low N) are the most important environmental constraints contributing to yield in stability of maize (Zea mays L.). Evaluation of maize genotypes under different stresses would be useful for identifying genotypes that combine stability with high yield potential for stress-prone areas. This study was conducted to (i) estimate stability of yield in maize hybrids developed from inbred lines with differential reactions to drought stress; and (ii) identify hybrids that combine stability with high yield potential across stress and non-stress environments. Methodology and results: Six hybrids, each formed by crossing drought tolerant x tolerant (TxT), susceptible x susceptible (SxS), T x S and S x T inbred lines and 4 checks were selected from 100 hybrids tested for two years under severe drought, mild drought, low N and high N; and for four years under optimal conditions, making a total of 12 environments in Nigeria. Combined analysis of variance showed that environments, genotypes and genotype-by-environment (GE) interaction effects were highly significant, suggesting that the hybrids responded differently relative to each other to a change in environment. Genotype and genotype-by-environment (GGE) biplot analysis explained 90%of the yield variation due to GGE. Most hybrids of T x T, T x S crosses were stable, while most S x T and S x S crosses were unstable across environments. Conclusion and application of findings: The study depicted severe drought stress as a representative test environment, indicating that selection of maize hybrids under drought stress would lead to yield improvement in low N as well as optimal growing environments. This study has identified four hybrids, (4058xFun.47-3), (161xKU1409), (KU1409x4008) and (1824x9432), that are stable and have high yield potential, however, they need to be tested further in multiple environments to confirm consistency of their stability