Abscission of flowers and loss of pods appears to be part of normal reproductive development in Vicia faba L. The biological processes leading to this loss of reproductive potential are yet to be elucidated, but appear to involve the lack of an adequate cytokinin supply to the reproductive organs. External application of cytokinins was used in this study to help further understand the regulation of reproductive loss in this species. The effect of six cytokinins on the reproductive potential of broad beans, grown under controlled conditions, was studied by local application of the chemicals on every inflorescence having flowers prior to and at full petal opening. 6-(benzylamino) purine (BA) and 6-[benzylamino-9-(2-tetrahydropyranyl)] purine (19tPIBA) were the most active compounds in preventing flower abscission, regardless of the flower position on the plant. However, this early increase in reproductive potential was eliminated due to compensatory pod-drop during their development. It was suggested in the discussion that repeated applications of these compounds may prevent abortion of the pods. In field experiments using various cultivars of V. faba L., the reproductive portion of plants sprayed twice, at early flowering and at early pod-initiation. Both BA-compounds resulted in almost complete flower retention. Among varieties, those that normally set fewer pods responded better to cytokinin treatment than varieties that normally achieved high levels of pod-set. The response of subspecies of Vicia faba to cytokinins in descending order was major>equina>minor. At harvest, analysis of cytokinin effects on yield components indicated a great variation in plants within each variety. Thus, recorded increases in the dry weight of harvestable organs were not statistically different from controls apart from cv. Toret, a quite uniform variety. Depending on the variety, consistent enhancement in fruit-set in faba bean due to BA-application was associated with increased sucrose activity and/or acid invertase activity at carpels before or at pollination, measured 24h after the application of the growth substance. Subsequently, an investigation of the inter-relationships between sucrose content of the carpel and successful pod-set after application of BA was performed.