The species ofIpomoea closely related to the sweet potato

Abstract

The problem of the origin of the sweet potato, Ipomoea batatas (L.) Lam., has both geographic and biosystematic aspects. The geographical locality where the sweet potato first occurred, or was first domesticated, is generally accepted to be the New World. Hypotheses of an Oceanian or African origin have been discounted by Conklin (2). Nevertheless, the sweet potato was evidently well distributed throughout the Pacific islands and reached even New Zealand in pre-Columbian times (16). Spanish and Portuguese travelers are believed to have disseminated the sweet potato through the tropics so rapidly that the impression was created that the sweet potato was pantropical in distribution prior to discovery of the New World. Although the actual geographical origin and the subsequent spread of the sweet potato throughout the world have ethnological implications, the geneticist or plant breeder is much more concerned with the origin of the sweet potato from related species. This interest is not a matter of idle curiosity. Reconstruction of sweet potato-like plants from related species should provide a new method of introducing useful variation, including disease resistance, to the sweet potato gene pool. In recognition of this fact, considerable emphasis has been placed on the species of Ipomoea