Biology, speciation, and utilization of peanut species

Abstract

Peanut, also known as groundnut (Arachis hypogaea L.), is a native new world crop. Arachis species originated in South America and are found in tropical and subtropical areas. Eighty-one species have been named (Krapovickas and Gregory, 1994; Valls and Simpson, 2005; Valls et al., 2013), including the domesticated peanut, A. hypogaea L. Species have evolved in highly diverse habitats and both annual and perennial types exist. New species are being discovered in areas that previously were very difficult to reach because of poor roads and transportation. It is likely that the genus originated in the highlands in the southwestern Mato Grosso do Sul region of Brazil close to Gran Pantanal where the most ancient species of the genus (Arachis guaranitica Chodat. and Hassl. and Arachis tuberosa Bong. Ex Benth.) are found (Gregory et al., 1980; Simpson and Faries, 2001). Subsequently, as the planalto continued to be uplifted coupled with water flow, the genus spread into the drier lowlands of South America (Gregory and Gregory, 1979; Stalker and Simpson, 1995; Simpson et al., 2001). The genus likely originated in tropical wetland areas and subsequently adapted for survival in dry environments.