"Every farming people have a staple food, plus a variety of other supplements. Historians, agronomists, and botanists have all contributed to showing the great variety of such foods within the pre-colonial African economy. There were numerous crops which were domesticated within the African continent, there were several wild food species (notably fruits), and Africans had shown no conservatism in adopting useful food plants of Asian or American origin. Diversified agriculture was within the African tradition. Monoculture was a colonialist invention."