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March 2009




New yam-growing technique promises more food, income for farmers


Farmers across Africa could look forward to higher yields with new propagation techniques. Credit: IITA

Ibadan, Nigeria - Yam farmers across Africa could look forward to better days ahead with the development of a tuber-less yam propagation technique by IITA and partners.

In this innovative approach, yam is propagated through vine cuttings, with carbonized rice husks as the growth medium. By eliminating the use of tubers, more yam is made available for food or for sale while signficantly lowering the risk of nematode infestation akin to using tubers as planting material. The technique also promotes faster multiplication and better and more uniform crop quality.

In the traditional system, tubers used as seed take up 30 to 50 per cent of the production cost. It is also quite inefficient: the resulting multiplication rate is only about 1:5-10. By comparison, cereals, for instance, have a propagation ratio of about 1:300.

“Our goal is to reduce the amount of yam tubers invested as seeds so that farmers will have more food and make more money,” says Dr Hidehiko Kikuno, IITA Yam Physiologist and project leader. He adds, “Another good thing about this technology is that the propagation medium - carbonized rice husks - could be obtained by farmers cheaply, even for free”.

The technology, which offers mass, rapid, clean and cost-effective method of multiplying yam, could effectively address the need for fast and wide distribution of high-quality improved varieties in order to meet the increasing demand for the crop.

Yam is a major staple in Africa. Average daily consumption per capita are highest in Bénin (364 kcal), Côte d’Ivoire (342 kcal), Ghana (296 kcal), and Nigeria (258 kcal). According to the FAO, in 2005, an estimated 48.7 million tons of yam were produced worldwide, with sub-Saharan Africa accounting for 97 per cent of this figure. The dietary and economic importance of the starchy tuber crop is also on the rise in a number of countries in Asia, Latin America, the Caribbean and Oceania.

The research is funded by the Japanese government, the Sasakawa Africa Association, Tokyo University of Agriculture and the International Cooperation Center for Agricultural Education, Nagoya University, Japan. Partners include the Tokyo University of Agriculture, National Root Crops Research Institute - Umudike, Nigeria, Crop Research Institute, Ghana and the Institute of Agricultural Research for Development, Cameroon. - IITA

More information:


Dr Hidehiko Kikuno, 
Yam Physiologist

Jeffrey T. Oliver, 
Corporate Communications Officer (International)




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