Evaluation Of High Altitude Orange Fleshed Sweetpotato (Ipomoea Batatas) Genotypes For Adaptability And Yield In Lowland Rainforest Ecology Of Umudike Southeastern Nigeria

Abstract

The orange fleshed sweetpotato (OFSP) which is so little known in Nigeria is extremely rich inbioavailable beta-carotene, which the body converts into vitamin A. As a result of the food benefit of OFSP, a full two year study was carried out at the experimental field of National Root Crops Research Institute-Umudike with the objectives to evaluate the yield and adaptability of the OFSP genotypes in Umudike rainfed forest agro-ecology of Southeastern Nigeria, to investigate the response of the foliage to sweetpotato virusdisease and the response of the roots to sweetpotato weevils and nematode diseases and pests prevalent in therainfed forest agro-ecology of Nigeria. The experimental design was randomized complete block designreplicated 3 times. Seven OFSP genotypes introduced from the highland areas of Uganda by the Sweetpotatobreeding unit of National Root Crops Research Institute- Umudike plus one national check variety were used inthe study. Data collected on total root number, large root number, percentage small root number, total root yield, large root yield, response of root to sweetpotato virus disease, root weevil and nematodes were statistically analyzed and means separated using standard error of difference means. Results obtained indicatedthat none of the OFSP varieties yielded more than the standard check variety. The consistent high percent smallroots indicated that the OFSP were not adaptable to the high virus pressure of Umudike, in the rainfed agro-ecology of Southeastern Nigeria. Based on the nutritive quality of higher beta- carotene fleshed colour oforange which was an improvement over the standard check variety 87/0087 (which has cream fleshed colour),the following varieties: Centinnial, 440293 and Shaba were selected for multilocational evaluation across theagro-ecologies to select areas their performance is location specific before final release to farmers