The ins and outs of manioc divertsity in Gabon, Central Africia : a pluridisciplinary approach to the dynamics of genetic diversity of Manihot esculenta Crantz (Euphorbiaceae)

Abstract

Manioc (Manihot esculenta Crantz subsp. esculenta, Euphorbiaceae) is the staple food and livelihood of more than half a billion people around the world, and ranks third, just behind rice and maize, as a source of calories in the tropics. Manioc was originally domesticated in the southern rim of Amazonia, and was introduced into Africa from Brazil by the Portuguese in the 16th century. Four hundred years later, it is now a major staple crop throughout Africa, and reached similar levels of genetic diversity to those encountered in its area of domestication, suggesting that despite the bottle-neck following its introduction, any losses of genetic diversity have been balanced by processes of restoration. Despite the economic importance of the crop in Africa, few studies have attempted to elucidate the origin of this diversity. This thesis addresses the mechanisms behind the secondary diversification of manioc in Africa.