Sweetpotato Viruses: 15 Years of Progress on Understanding and Managing Complex Diseases

Abstract

Sweetpotato is a member of the morning glory family that is thought to have originated in Central or South America but also has a secondary center of diversity in the southwest Pacific islands. It is grown in all tropical and subtropical areas of the world and consistently ranks among the 10 most important food crops worldwide on the basis of dry weight produced, yielding about 130 million metric tons per year on about 9 million hectares. Sweetpotato is an important crop for food security. It has been relied on as a source of calories in many circumstances. Vines and/or storage roots can be used for direct human consumption or animal feed. Growing awareness of health benefits attributed to sweetpotato has stimulated renewed interest in the crop. Orange-fleshed cultivars, a source of vitamin A, were introduced to developing countries with hope that they would replace the white-flesh varieties and help alleviate vitamin A deficiencies. In East Africa, sweetpotato virus disease, which is caused by the synergistic interaction of the whitefly-transmitted crinivirus and the aphid-transmitted potyvirus, can cause losses of 80 to 90% in many high-yielding genotypes. During the past 15 years, as molecular methods have been adopted, much has been learned about the composition of the sweetpotato virus complexes, the effects of virus diseases on production systems, the biology of the virus–plant interaction, and management approaches to sweetpotato virus diseases. This article is intended to summarize what has been learned since earlier reviews, integrate knowledge gleaned from experiences in tropical and temperate production systems, and suggest courses of action to develop sustainable management programs for these diseases