Performance of intermediate maturing Maize cultivars in drought-stressed and non-stressed environments in Ghana

English

Drought stress is a major production constraint of maize (Zea mays L.) in the Iowland tropics. A study was conducted to determine the yield potential and stability of five maize hybrids, three improved composites, and one local maize variety in favourable and drought-stressed maize production environments in Ghana. The nine genotypes were evaluated at a total of 20 sites in the major agro-ecological zones of Ghana from 1995 to 1997. The 20 sites were divided into two environments (stress and non-stress) of 10 sites each, based on rainfall data during the growing season. Effects due to genotype (G), location (L), and G x L interaction were highly significant (P<O.OI) for mid-silk, plant height, ear.acceptability, lodging, and grain yield in the stressed and non-stressed environments. Grain yields averaged 3.58 Mg ha-l in the stressed environment and 6.67 Mg ha-l in the non-stressed environment. On the average, the hybrids out-yielded the improved composites by 17.3 per cent and the local variety by 50.7 per cent in the stressed environment. In the non.stressed environment, the hybrids had an overall yield advantage of 1 1.6 and 60.2 per cent over the improved composites and the local variety, respectively. Estimates of Eberhart and Russel's stability parameters across both environments for gain yield were b 0.006 for the hybrids; b 1.00, s.z for the improved composites; and b I sa = 0.008 for the local variety. It was concluded from the study that the hybrids were more productive than the improved composites in the favourable as well as in the stressed environments, the hybrids were as stable as the improved composites across these diverse environments, and that the local variety showed Iow yield potentials in both environments.

Obeng-Antwi, K.; Sallah, P. Y. K.; Frimpong-Manso, P. P.