Comparative effects of neem extracts and storage methods on the quality of white yam (Dioscorea rotundata)

Yam ( Dioscorea spp. L.) is an important cash and industrial crop of high quality but with huge postharvest losses. This study was carried out to investigate the effect of neem extracts and storage methods on quality of white yam ( Dioscorea rotundata L.). Yam tubers were obtained from farms in Makurdi. The tubers were selected based on their sizes, absence of physical signs of damage and visual symptoms of disease and defects. Neem leaf and bark were also collected in Makurdi town and taken to the laboratory for preservative experiments. The experiment was a 3 × 3 factorial in a completely randomized design with three treatments (Neem leaf, Neem bark and control) and three storage methods (racks, barns and trench silos). The experiment lasted for a period of 6months and readings were taken at intervals of 30days during this period. Higher percentage weight loss was reported for yams treated with Neem bark (18.14%) compared to yams treated with Neem leaf (17.98%) and control yams (18.05%). Higher percentage weight loss was recorded for yams stored on barns (18.95%) compared to storage in rack (15.12%) and trench silos (17.82%. Interaction effect of Neem extracts and storage methods, yams treated with Neem bark and stored in barns recorded higher weight loss (20.60%) compared to other treatment combinations. In terms of marketability, higher marketability was recorded for yams treated with Neem bark and stored on racks (4.00) while least marketability was recorded for control yams stored in trench silos (2.50) and yams treated with Neem leaf and bark but stored in barns (2.50 each). A higher decay was recorded for control Yams stored in trench silos (32.86) while yams treated with Neem bark and stored on rack recorded the least decay (7.14%). Sprouting was significantly higher in trench silos for both control and Neem bark treated yams (15.71%). The shelf life was significantly higher in yams treated with Neem bark and stored on racks (98.71%) while germination was highest for yams treated with neem and stored on racks (98.71%). It was concluded that Neem leaf and bark is capable of preserving the weight of stored yam tubers and marketability to farmers. Their storage in racks also provides better quality for stored yams. It is therefore recommended that if yams will be stored for extended periods of time above four months, then Neem bark should be adopted due to its high preservative ability.