The Origin and Evolution of Gossypium

The genus Gossypium has a long history of taxonomic and evolutionary study. Much of this attention has been stimulated by the fact that the genus includes four domesticated species, the New World allopolyploids G. hirsutum and G.barbadense (2n = 52), and the Old World diploids G. arboreum and G. herbaceum (2n = 26). These cultivated species embody considerable genetic diversity, but this diversity is dwarfed by that included in the genus as a whole, whose 50 species have an aggregate geographic range that encompasses most tropical and subtropical regions of the world.