ABSTRACT

Two field experiments were conducted to study the responses of five white yam cultivars to three harvesting dates during June 2016 and June 2017 cropping seasons in a tropical ultisol of south eastern Nigeria. The experiment was a 5 x 3 factorial arrangement laid out in a randomized complete block design (R C B D) with five replications. Treatments comprised all possible combinations of five white yam cultivars (Adaka, Ame, Amula, Hembamkwase, and Yandu) and three harvest dates (8, 16, and 24 weeks after planting). Cultivar did not significantly (P ≥ 0.05) affect percent establishment, vine length, total leaf area, tuber bulking, number of tubers per plant, tuber weight and tuber yield, but Hembamkwase had thicker vines than Amula and Adaka.  Increasing the harvesting date from 8weeks after planting to 24weeks after planting increased significantly (P ≤ 0.05) tuber bulking, number of tubers per plant, tuber weight and tuber yield. Tuber yield at 24 weeks after planting, which produced the highest yield was higher than the yield at 8 and 24 weeks after planting by 356% and 136%, respectively on average. Based on this results, early planting is recommended to ensure the crop goes through a growing season of about 8 to 10 months that would allow for ample vegetative growth and the manifestation of the full genetic potentials of the cultivars.