Orange-fleshed sweet potato, high in provitamin A carotenoids, were introduced to Africa from the United States, but there was a shortage of varieties with desirable traits for South African conditions, namely, stable yield, good total carotenoid content, and good taste. Desirable characteristics were combined annually through the polycross method using parents selected for specific traits, followed by clonal selection phases and multi-location advanced yield trials. Genotype by environment analysis of advanced lines indicated two locally bred lines, 1998-21-1 (released as “Impilo”) and 1999-1-7, as the best. Other useful clones were 1999-6-1 (released as “Khano”) and U.S. variety “Resisto.” These were recommended for use in food-based approaches to address vitamin A deficiency. In addition, three new promising lines were identified, viz., 2001-5-2, 2000-6-1, and 2000-10-7, which needed to be evaluated in multi-location trials to determine their adaptability. Future breeding efforts could concentrate on higher levels of total carotenoids and stable high yields, and in addition, on tolerance to drought and Alternaria stem blight.
Journal of Crop Improvement (2009) 23 (3) 235-251 [doi: 10.1080/15427520902774298]