SUMMARYYam minisett technique (YMT) has been promoted throughout West Africa since the 1980s as a sustainable means of producing clean yam planting material, but adoption of the technique is often reported as being patchy at best. While there has been much research on the factors that influence adoption of the technique, there have been no attempts to assess its economic viability under ‘farmer-managed’ as distinct from ‘on station’ conditions. The present paper describes the results of farmer-managed trials employing the YMT (white yam: Dioscorea rotundata) at two villages in Igalaland, Kogi State, Nigeria. One of the villages (Edeke) is on the banks of the River Niger and represents a specialist yam environment, whereas the other village (Ekwuloko) is inland, where farmers employ a more general cropping system. Four farmers were selected in each of the two villages and asked to plant a trial comprising two varieties of yam, their popular local variety as well as another variety grown in other parts of Igalaland, and to treat yam setts (80–100 g) with either woodash or insecticide/nematicide+fungicide mix (chemical treatment). Results suggest that while chemical sett treatment increased yield and hence gross margin compared with woodash, if household labour is costed then YMT is not economically viable. However, the specialist yam growers of Edeke were far more positive about the use of YMT as they tended to keep the yam seed tubers for planting rather than sell them. Thus, great care needs to be taken with planning adoption surveys on the assumption that all farmers should adopt a technology.
Aspects of the Biology of Protopterus annectens from Agenebode at River Niger, Nigeria
