Breeding of sweetpotato and evaluation of imported cultivars in South Africa

The ARC-Roodeplaat sweetpotato (Ipomea batatas) breeding programme aims at developing sweetpotato cultivars which have good yield and storage root quality combined with sweet and dry taste, early maturity, good keeping ability and drought tolerance. Additionally high beta-carotene content is of great importance. The virus-tested glasshouse collection of 263 local and 52 imported accessions serves as basis of the programme. The breeding activities at Roodeplaat included importation of novel germplasm, polycrossing (5309 seeds), stringent selection at the 3116 seedlings in the seedling nursery, selection of 85 entries from the preliminary yield trial, 10 from the intermediate yield trial and 8 from the advanced yield trial. The most promising cultivars/lines were evaluated at various sites involving farmers in selection for taste acceptability. The result of these trials during 2000/01 and 2001/02 at four sites, is the release of seven new cream-fleshed cultivars and one land race for production in South Africa namely: Ndou (1995-13-2), Monate (1989-17-1), Mokone (1987-16-1), Letlhabula (1995-10-1), Phala (1984-2-201), Amasi (1985-6-3), Mamphenyane (1984-10-340) and Natal Red. The orange-fleshed cultivars, cultivars Excel and W-119 from the USA, and A45 coming from the breeding programme at University of Natal, South Africa, are recommended. Improved ARC lines/cultivars and imported cultivars were also supplied to SADC countries for evaluation.