Productivity of Sweet Potato (Ipomoea batatas L.) as Influenced by Water Stress and Variety in Sokoto Sudan Savannah, Nigeria

Field trial was conducted at the Usmanu Danfodiyo University Sokoto Teaching and Research Fadama Farm, Sokoto, during the 2015 dry season. The objective of the research was to determine the productivity of sweet potato (Ipomea batatas L.) as influence by water stress and variety in Sokoto, Treatments consisted of factorial combination of water stress imposed at vegetative growth phase, tuber initiation growth phase, and control (unstressed), three variety of sweet potato Ex-Bakalori, Ex-kano and Ex-Fateka, laid out on a split plot design replicated three times, water stress was allocated to the main plot and variety was assigned to the sub plot. The result indicated that water stress and variety had no significant effect to leaf number, vine length, and leaf area index (LAI) at 3, 6, 9, 12, 15, and 18 Weeks After Planting (WAP). Interactions between water stress and variety also have shown no significant different to number of leaves per plant, vine length, and leaf area index. Similarly vine yield and culled tuber weight indicated no significant effect to water stress and variety. Water stress significantly affected the number of tubers per plants, number of marketable tuber per plants and number of non-marketable tuber per plant, average weight of marketable tubers and tuber yield t ha-1. Water stress imposed at vegetative and control (unstress) plots did not differ significantly but differed significantly from plots imposed with water stress at tuber initiation with higher, number of tuber per plant, marketable tuber per plant and tuber yield t ha-1. Water stress at the tuber initiation plots produced smaller tubers and lower tuber yield. Therefore water stress at tuber initiation should be avoided for maximum yield of sweet potato.