Performance of Hand-pollinated Maize Genotypes at Different Daytimes in a Nigeria Forest Agro-ecosystem

Weather condition prevailing during pollination could have some effect on seed set and yield in maize. A controlled pollination experiment was conducted at the Teaching and Research Farm, Ekiti State University, Ado-Ekiti, Nigeria during the early seasons of 2007 and 2008 to investigate the effect of daytime on the performance and seed yield of five maize genotypes viz. two open pollinated, two inbred lines and one hybrid. Hand-pollination was done on an hourly basis between 09.00 to 18.00 hours which constituted the treatments. The ten treatments were laid out in a Randomized Complete Block Design with three replicates. In all the experimental units, five plants were bulk pollinated for each of the time treatment. Results indicated differential responses of the genotypes to time of pollination. When averaged across the five genotypes, there were significant (p<0.05) differences in cob length, weight of 100 seeds weight, and seed yield per cob for the two years whilst cob diameter and number of kernels per row were only significant in 2008. Hand-pollination of maize can be done between 09.00 and 18.00 hours, however, the optimum performance was obtained for cob and seed traits when pollination was done between 10.00 and 12.00 hours, There was 36.65% reduction in seed yield per cob when pollination was delayed till 16.00 hours compared with when done at 10.00 in 2007 and 32.94% reduction between 11.00 and 17.00 hours in 2008. The rate of decline can be minimized when pollination is delayed till 18.00 hours when temperatures are relatively low, which implies that perhaps the most determining factor that precludes pollination is temperature which is comparatively high between 13.00 and 17.00 hours. Furthermore, suboptimum performance was observed when pollination was done at 09.00 hours possibly due to the dampness of the pollen which may impair pollen shedding.