Colonial governments played an essential role in prolonging and intensifying the diffusion of the crop throughout West and East Africa and many parts of Central Africa during the first half of this century. This period was probably the most important in extending the area of the crop's cultivation beyond the humid tropics. This encouragement of cassava cultivation by colonial governments may often have taken place in a manner insensitive to the applicability of cassava to local farming systems and food habits.

Moreover, many colonial governments displayed an ambivalent attitude towards cassava. Whilst it was introduced as an anti-famine and anti-locust crop, cassava was also thought to promote laziness, soil depletion and malnutrition.

Post-independence diffusion of the crop in Africa has primarily been the result of local processes of migration and agricultural change. There is ample evidence of the willingness of African farmers to experiment with and search for new crops and varieties. Cassava's special characteristics make it well adapted to farmers' risk aversion strategies and allow it to be grown under a great diversity of circumstances and changing economic conditions.

For example, in central Zaire, a comparison of data from colonial reports with present varieties (as acknowledged by farmers) suggests that an increasing number of varieties is grown and that the names of many of these point to recent introductions from neighboring areas or beyond.