Evaluation of yield response of selected water yam (Dioscorea alata L) genotypes to different seasons

Six water yam (Dioscorea alata L.) genotypes were evaluated alongside a popular cultivar in the locality for yield and yield components in the wet and dry seasons of 2009 and 2010 at Iwo (Lat. 70 38’ N, Long. 40 11’ E), Osun state Nigeria. The experiments were laid out in a Randomized Complete Block Design (RCBD) with three replications. Results indicated significant effect of genotype on the traits studied. Among the genotypes evaluated, genotypes with potentials for high-tubers production were identified. The genotype, TDa 98/01176 produced the highest total number of tubers and number of seed tubers per plot. However, TDa 99/00240 had the highest ware tubers and total fresh tuber yield. The lowest values for these traits were obtained for Onisumose, a landrace genotype. There were no significant differences among the genotypes performance in 2009 cropping season compared to 2010 cropping season. The four genotypes TDa 99/00240, TDa 99/01169, TDa 99/01166 and TDa 98/01176 had the most stable high yield across the two cropping seasons. Generally, farmers would prefer to use a high yielding genotype that performs consistently across different seasons and environment. Genotype yield and stability of performance over two different cropping seasons as in the case of wet and dry seasons would be necessary for evaluation of genotype performance. In both seasons, the most outstanding genotype was TDa 99/00240 having values that were highest among the means for all the major yield traits.