The number of tubers produced stand-1 planted with a single sett was investigated for white and yellow guinea yams (Dioscorea rotundata Poir. And D. cayenensis is Lam., respectively). The number of tubers stand-1 ranged from 1 to 11; 72.7% of the plants each produced a single tuber and 19.6% produced two tubers. The distribution of the number of tuber stand-1 was of the Poisson type. Generally, yellow yam clones produced 2.5 times more tubers stand-1 than white yam clones. Multiple tubering tended to increase with progressive clonal propagations and was not compensatory with weight of individual tubers in determining total tuber yield stand-1. Beyond two tubers stand-1, tuber proliferation had strong adverse effects on the quantity and quality of ware tubers produced. There was a positive association between the number of tubers stand-1 and the number of primary vines produced stand-1; and this seemed to be related to the type and health of the planted sett as well as to post-planting soil activities regulating the number of sprouts that emerge.