Genetical variation in morphological characters, flowering behavior, and seed and tuber productivity of 41 winged bean accessions collected from eight countries were assessed in Ishigaki Island (24°N lat.).
　The range and mean value of morphological characters such as pod-length, 100-seed weight and the number of seeds per pod were similar to those reported earlier except the maximum pod length. There was much difference in earliness of flowering ranging from very early-flowering in August to late-flowering in November, although most accessions began to flower in October. The highest seed yield was shown in two very early-flowering accessions from Papua New Guinea, while late-flowering accessions from Indonesia gave very poor yield. The seed yield was dependent on different length of podproducing period with more than 20°C of mean air temperature. On the contrary, the very early-flowering accessions did not produce any tuber at all, but the late-flowering ones gave good tuber yields. The possibility of productive winged bean culture in Okinawa will be materialized by solving the climatic disadvantage such as long day-length in the warm season of Okinawa with the use of day-neutral cultivars.