Collection, Characterizaton and Conservation of Genetic Resources of Yam Cultivars From Ekiti State, Nigeria
Abstract This study was initiated to restore the genetic resources of yam which had been decimated in a core yam-producing community in Ekiti State, Southwestern Nigeria. Twenty cultivars, consisting of Dioscorea rotundata, D. cayenensis, D. alata, and D. dumetorum were identified, collected, characterized and multiplied using an On-farm Participatory Method. The yam cultivars were characterized for quality and yield of pounded yam (iyan) as well as starch properties. They were later conserved in the Teaching and Research Farm of the Obafemi Awolowo University Ile-Ife.Morphological characterization separated Dioscorea alata (Ewura) by its winged vines while Dioscorea dumetorum (Esuru) was separated by its pubescent spines, trifoliate leaf with acute apex and base and the clustered, irregularly-shaped tuber. All the tubers of the yam cultivars had high storability. Pounded yam quality rated the Ikumo and Ajimokun cultivars as best while Odo was rated average and this was attributed to the swelling properties and amylose content of these cultivars. Yam cultivars with high granules had low swelling capacities. The Brittle Fraction Index of the starch from all the cultivars was lower than 1.0 explaining why the iyan they produced had no crust on the surface and kept for long hours after preparation.From this study, it was concluded that the local yam cultivars collected represent the core of yam genetic resources for utilization in the region. These cultivars are therefore recommended for prioritization in further studies on propagation, conservation and improvement so that a narrow genetic base of cultivars is not encouraged, for example, by promoting cultivars whose vines perform well in tuberization.