Effect of plant spacing and variety on weed and performance of orange-fleshed sweet potato in humid agro-ecological zone of Nigeria

Abstract

Among the crops grown in the tropics, sweet potato ranks second after cassava. Field research was conducted at the National Root Crops Research Institute, Umudike, south-eastern Nigeria, to evaluate the response of orange-fleshed sweet potato varieties to intra-row spacing. Treatments included four varieties (Umuspo 1, Umuspo 3, Ex-Igbariam and Ex-Oyunga) and three intra – row spacings (20, 30 and 40 cm). Weed density and growth decreased, but sweetpotato leaf area index (LAI), fresh shoot biomass and storage root yield increased significantly (P<0.05) at the closer spacing (20 cm) than at the wider spacings (30 and 40 cm). Umuspo 1 had higher LAI and shoot biomass; and suppressed weeds more than other varieties. Also, storage root yield of Umuspo 1 (27.2t/ha) was significantly higher than that of Umuspo 3, Ex-Igbariam and Ex-Oyunga by 35, 103 and 325%, respectively.Keywords: Plant spacing, variety, yield, orange-fleshed, sweet potato, Nigeria