Breakthrough in yam breeding

Before the prolonged civil war in Sudan and drought in Ethiopia, farmers in those countries were planting white yams (Dioscorea rotundata). But now yam has almost completely disappeared from these countries because the planting portion of the crop also happens to be the edible portion. Farmers expect to set aside at least one quarter of their annual harvest for replanting but whenever farmers, for one reason or another, consume all the yams they have, the crop's genetic base is eroded. This is what has happened in Sudan, Ethiopia and other crisis-ridden African countries where yam culture flourished in the past. It is almost impossible to recreate yam germplasm because the crop responds poorly to conventional plant breeding techniques. Unlike some other crops, where the male and female flowers are on the same plant, yam flowers are borne on separate plants and the flowering of male and female plants is difficult to synchronize. Also, flower thrips, the insects that pollinate most yam flowers, are not very efficient which results in the abortion of many female yam flowers. However, scientists at the International Institute of, Tropical Agriculture (IITA) in Ibadan have achieved a break- through in yam, breeding based on the Institute's large germplasm collection of new yam genotypes with better flowering qualities, which can be manipulated by breeders to generate new varieties. With the development of the new genotypes of yams through seed, new materials are being made available by IITA both in seed and tissue culture form. Requests have already been received from Rwanda, Guinea, Gambia, Guinea Bissau, Kenya and Equatorial Guinea. Sudan Uganda and Malawi have also shown interest and it is hoped that in the near future yam culture will expand to cover the rest of the African continent, particularly East and central Africa. CGIAR Secretariat, 1818 H Street, NW Washington, D C 20433 USABefore the prolonged civil war in Sudan and drought in Ethiopia, farmers in those countries were planting white yams (Dioscorea rotundata). But now yam has almost completely disappeared from these countries because the planting portion of the crop..