Exploration of the tuber production potential of yam bean (Pachyrhizus erosus (L.) Urban) under field conditions in Sierra Leone

Yam bean (Pachyrhizus erosus) is one of the few tuber forming legumes with excellent multipurpose qualities and uses. Its production potential for it subsequent adoption into the farming system in Sierra Leone was evaluated. Preliminary trials for varietal evaluation with no agricultural inputs showed that the crop has great capability for increased tuber yields. Fresh tuber yield ranged from 10,190 kg/ha to 22,870 kg/ha. Out of fifteen varieties supplied by CERAAS, four (EC 201, EC 550, EC 114 and EC 117) were selected on the basis of yield potential for further crop development. To enhance maximum tuber production, the effect of fertilizer application and reproductive pruning on these four varieties was investigated. Reproductive pruning strongly influenced tuber production and resulted in an overall yield increase of 251%. Nitrogen fertilizer application had no effect on tuber yield. Pachyrhizus erosus was found to be most sensitive to water stress during reproductive stages with significant reduction in flower and pod production. Under the prevailing conditions tuber production was found to be greater in plants stressed before pod formation and during reproductive pruning. These findings provide evidence of the potential productivity of Pachyrhizus erosus and serve to justify the need for its introduction into farming systems in areas with low edaphic conditions for agricultural development and sustainable food production.