Winged bean (Psophocarpus tetragonolobus(L.) DC.)

Abstract

The winged bean (Psophocarpus tetragonolobus) is one of six species of the genus Psophocarpus and the family Leguminosae (Fabaceae). Psophocarpus tetragonolobus is a twining, perennial herbaceous plant that is characterized by its tuberous roots and its winged pod. All species in the genus have tuberous roots and winged pods and are therefore technically all winged beans. Because P. tetragonolobus has been most extensively studied, the term winged bean is currently used almost exclusively for this species. Although the winged bean is perennial, it is most usually cultivated as an annual, because for pod and seed production (but not for root yield), productivity is higher in the first year than in the second year. Banerjee et al. (1984) found that fresh tuber weights may be 80–230 g in the first year of growth, and as high as 369–392 g per plant in the second year. Length of the winged pod averages 30 cm (Pospisil et al, 1971). The number of pods per plant in the first year ranges from 60 to 77 (Banerjee et al, 1984) or more depending on level of fertilization and availability of moisture.