Groundnut, Arachis hypogaea L. (also called peanut in English, mani in Spanish, amondoim in Portuguese, pistache in French, mungphali in Hindi and ying zui dou in Chinese), ranks 13th among food crops and annual oilseed crops (FAO 1995). Its high oil and protein contents serve important needs for food, energy and industrial uses. Although a native of South America, the crop is now cultivated in tropical, subtropical and warm temperate regions of the world extending from 40°N to 40°S.

BOTANY AND DISTRIBUTION

Arachis hypogaea L. is a member of family Leguminoseae-Papilionoideae, tribe Aeschynomeneae and subtribe Stylosanthinae. It is a tetraploid with 2n=40. Krapovickas and Gregory (1994) divided the genus Arachis into nine sections. Section Arachis contains cultivated groundnut, A. hypogaea, another tetraploid species A. monticola Krapov. & Rigoni and a number of wild diploid species. Gregory et al. (1973) earlier divided A. hypogaea into two subspecies, fastigiata Waldron and hypogaea Krap. et Rig., and each subspecies into two botanical varieties. According to the new classification, subsp. fastigiata is subdivided into four botanical varieties, fastigiata, peruviana Krapov. & W.C. Gregory, aequatoriana Krapov. & W.C. Gregory and vulgaris C. Harz. The two botanical varieties in subsp. hypogaea are hypogaea and hirsuta Kohler. The key for identification of different botanical varieties is given in Box 9.1.

Origin, Domestication and Diffusion

The genus Arachis is naturally restricted to Argentina, Bolivia, Brazil, Paraguay and Uruguay in South America.