SE Asian food-crops and the Bantu expansion     
*The early introduction of these humid-zone cultigens must have had important consequences for African prehistory.
*The region of greatest somatic diversity of these crops corresponds well to the area of the Bantu, Bantoid and Benue-Congo-speaking peoples. Johnston (1919-1922)  originally proposed the idea that the Bantu homeland was to be located in present-day Cameroun. The date generally advanced for this is >3000 BP.
*Although the route travelled by SE Asian cultigens remains quite obscure, it seems credible that their impact on existing agricultural societies in the Bight of Benin must have been considerable.
*It is likely that a combination of iron technology and three new high-yielding staples that could be grown successfully in the tropical rain-forest permitted the second, and most dramatic, phase of Bantu expansion.
*New finds in Southern Cameroun now provide direct evidence for agricultural tools in the rainforest (Eggert et al. 2006). Moving South and East, presumably along the waterways the Bantu seem to have rapidly colonised the equatorial forest.
*The conjunction of these crops and at least some iron tools to make easier the clearing of the forest may have been the combination of factors that permitted the colonisation of half the continent in a relatively short period of time.