Optimum planting dates for four maturity groups of maize varieties grown in the Guinea savanna zone

Abstract

Five maize varieties, comprising NAES EE W SR (extra-early, normal maize (NM)), Dorke SR (early, NM), Abeleehi (intermediate, NM), Obatanpa (intermediate, quality protein maize) and Okomasa (late, NM), were sown at 2-week intervals from mid-May to last week of July in 1993 and 1994 at Nyankpala in the Guinea savanna zone. The varieties were assigned to main-plots and planting dates to sub-plots in the randomized complete block with four replications per year. Effects due to variety and planting date were highly significant (P< 0.01) for grain yield. The variety W planting date interaction was not significant for yield. Grain yields averaged over planting dates were 3890, 5252, 5798, 5830, and 5883 kg/ha for the varieties NAES EE W SR, Dorke SR, Abeleehi, Obatanpa and Okomasa, respectively. Grain yields for the six sowing dates averaged over varieties were 5919, 5900, 6232, 4895, 4537 and 4502 kg/ha. Grain yields for the first three planting dates did not differ significantly from each other. Similar results were obtained for the last three planting dates. Yields on the average were 30 per cent higher for the first three planting dates than for the last three. Plant dry matter yield, number of ears per plant and thousand grain weight were the parameters which showed significant positive correlations with grain yield among planting dates. The data showed that (1) for all maturity groups, maize sown from mid-May to mid-June significantly out-yielded the later plantings, (2) the extra-early and early maize varieties were lower yielding than the later varieties, and (3) there was no yield advantage in the late varieties over the intermediate types in the Guinea savanna zone.
(Ghana Journal of Agricultural Science, 1997, 30(1): 63-70)