Effect of some botanical extracts on post-harvest losses of yam (Dioscorea rotundata) in improved yam barn in Nigeria

  Two storage experiments in an improved yam barn were carried out simultaneously at two locations in southern Nigeria to determine the influence of cultivar, botanical storage treatments and storage environments on the shelf life of yam (Dioscorea rotundata). The experiments were conducted from January to July. The temperature use efficiency (TUE) of the storage barn in Umudike increased with increase in time of storage up to April and then declined. At Nsukka, the TUE also increased with increase in time of storage even at a higher rate than what was recorded in Umudike. Dormancy period of yam tubers varied significantly (P ≤ 0.05) in the two locations with or without botanical storage treatments. Similarly, botanical treatment effects on the dormancy varied significantly (P ≤ 0.05) with Casia alata taking the lead in Umudike while Azadiracha indica had the highest effect (dormancy extension) in the Nsukka location. The mean rot incidence was lowest where C. alata was applied in the two locations followed by A. indica while mean rot incidence was highest with no treatment control. In this study, C. alata and A. indica leaf extracts showed outstanding performance in their potential abilities on reduction of post-harvest losses of yam.   Key words: Dormancy, weight loss, plant extracts, yam cultivar, improved barn.