Evaluation of sweetpotato for early maturity across different agro-ecological zones in Ghana

Abstract

Multilocational trials were conducted in the coastal savanna, forest and forest/savanna agro-ecologies of Ghana in 1996 and 1997 to identify early-maturing sweetpotato varieties. Seven genotypes (including a local check) were evaluated in five locations. Plants were sampled for tuber yields and other characteristics at 3, 4, 5 and 6 months after planting (MAP). Sweetpotato is normally harvested at 4 MAP, so the fresh and dry tuber yields and biomass production of the genotypes at 3 MAP gave an indication of their early -maturity potential especially when compared with the yields of the local variety (the check) at 4 MAP. Using these criteria, TIS 8266, TIS 84/0320, TIS 86/0350, TIS 3017, Sauti and Dugbadza were identified as early-maturing in the coastal savanna agro-ecology. In the forest agro-ecology, all the genotypes except TIS 86/0350 were also early maturing. In the forest/savanna transition zone, there were no significant tuber yield differences between the genotypes at 3 MAP and the local variety (Local Red) at 4 MAP. Similar results were obtained with the dry tuber yields and biomass production in the three agro-ecologies. They could, therefore, be considered as early maturing. Percent dry matter in all genotypes were high from the earliest to the latest harvesting (three to six months after planting) in all agro-ecologies. Key Words: Ghana, harvest index, Ipomoea batatus, maturity period, tuber yield (African Crop Science Journal 2001 9(1): 25-32)