The sweetpotato belongs to a single species, Ipomoea batatas (L.) Lam. In Spanish, the most common names are batata, camote and boniato; in French, patate douce; in Portuguese, batata doce; in Italian, batata dolce; in Chinese, gan shu, and in Quechua, the Inca language, kumara or apichu. In the United States, the deep orange, moist-fleshed cultivars are sometimes mistakenly called yam, which belongs to the totally different genus Dioscorea.

Sweetpotato is the world's seventh most important food crop after wheat, rice, maize, potato, barley and cassava. It is grown in more developing countries than any other root crop. World sweetpotato production is around 124 million t in an area of about 9.2 million ha.

BOTANY AND DISTRIBUTION

The sweetpotato and the wild species closely related to it are classified in the family Convolvulaceae, genus Ipomoea, subgenus Eriospermum, section Eriospermum (formerly Batatas) and series Batatas (Austin and Huamán 1996).

Linnaeus described the cultivated sweetpotato in 1753 as Convolvulus batatas. In 1791, the botanist Lamarck described it as Ipomoea batatas. It is a hexaploid plant with 2n=6x=90 chromosomes, although some plants morphologically quite similar to I. batatas with 2n=4x=60 have been described and named, but they are considered synonyms of this species (Austin 1977).

Origin, Distribution and Diffusion

Abundant evidence shows that sweetpotato was spread widely through the migration routes of people in the New World tropics before the discovery of America.