There are generations of studies of domesticated plants such as wheat, rice, potatoes etc, in Europe, the Middle East as well as in Asia and the Americas. These studies range from Genome sequencing of plants to plant domestication but Africa has very much lagged behind. Little is known about the genes or DNA of most of the indigenous plants in the continent and as such, they haven’t been improved genetically. However, there have been recent efforts by international researchers to fill in these gaps.
In 2007, a group of international scientists from International Institute of Tropical Agriculture (IITA), in Nigeria, the Japan International Research Centre for Agricultural Science (JIRCAS), the Iwate Biotechnology Research Centre (IBRC), Japan, and the Earlham Institute and The Sainsbury Laboratory of the United Kingdom, finally revealed the full genome sequence of one of Africa’s poorly understood but vitally important crop – the white Guinea yam (Dioscorea rotundata Poir.).
Recently a team of researchers from France’s Institute for Research and Development after sequenced 167 genomes of wild and domesticated yams collected from West African countries such as Ghana, Benin, Nigeria, and Cameroon, was reported have found that yams were domesticated from the forest wild yam species, D. praehensilis in the Niger River basin. Researchers had believed yams may have been domesticated from a different species that thrive in Africa’s tropical savanna as though the DNA of savanna wild yams was fairly similar, but the forest wild yams split into two groups, one centred in Cameroon and another much farther west. They further identified forest yams in the Niger River Basin, between eastern Ghana and western Nigeria, as the source of the modern domesticate.
According to the report, their analysis could not pinpoint the date of domestication, but it did find genes that changed along the way. Variations in genes for water regulation probably helped convert a forest dweller into a plant that thrives in the open sun. Alterations in root development and starch production genes also likely made tubers regularly shaped and richer in starch.
This explains why yam is very central in Nigerian and Ghanaian culture aside been a very important food and cash crop in West Africa including countries such as Ivory Coast, Ghana and Nigeria. It is so central to the culture of many Nigerian societies where it is reverend that it has its own festival – the New Yam Festival. It is used as marriage dowries and a measure of a household’s social standing. It is a major source of dietary calories and the, most important cash crop in Nigeria worth nearly $14 billion annually; one-third of Nigerians, nearly 60 million people depend on yams as a main source of income. It was the most important root crop in Africa before the introduction of cassava in the 1500s and still more important than maize in parts of Africa.
African rice (Oryza glaberrima), which has been mostly replaced with Asian rice (O. Sativa) was also found to have been first domesticated in the Niger River basin too, northern Mali precisely.
Read about the Lost or Orphaned Crops of Africa here