Maize.
"Throughout most of the country, however, South African cuisine relies on meat and mielies. Many South Africans, black and white, would cheerfully go through their lives eating little else. Up to half the arable land in South Africa is planted with maize, which was grown by tribes across Southern African long before the colonists arrived. https//web.archive.org/web/20060720101224/http://www.southafrica.info/plan_trip/holiday/food_wine/920091.htm