Influence of growth-promoting substances on sprouting of white yam (Dioscorea rotundata) setts

Abstract

Planting material alone accounts to 25-30% of production cost in yams. One partial solution to this problem is reduction in sett size. However, in most yams and in particular, Dioscorea rotundata sprouting percentage is low and sprouting process is slow and staggered especially when small setts derived from different tuber portions viz., head, middle and tail are planted. Hence in this study, five growth promoting substances (thiourea 2%, potassium nitrate 2%, IAA 1000 ppm, wood ash and cowdung slurry) and an untreated control were evaluated for their effects on sprouting and emergence of white yam setts in completely randomised design. Sett treatment using thiourea 2% proved consistently better and induced early (47 days) and uniform sprouting. Highest percentage of sprouting (23% by 30 days and 40% by 45 days) was also observed with thiourea treatment. Thiourea also produced longer sprouts that eventually led to the establishment of a vigorous crop. The effect of potassium nitrate on sprouting and establishment was not pronounced. The farmer’s practice of dipping the setts in cowdung slurry or smearing with wood ash as well as the untreated setts resulted in poor, slow and staggered sprouting. IAA had the l;east effect.Thiourea treatment proved feasible to reduce the time from planting to field emergence.Not Available