Abstract
1. Number of days from sowing th flowering date of soybean plants showing varietal difference was shortened at a little over 4%∼27% under the comparatively warm night temperature and by the hotbed culture of seedlings compared with each control. In these experiments, the acceleration ratio of flowering under the comparatively warm temperature differs from that of hotbed culture of seedlings. 2. Flowering of 6 varieties was elongated and 2 shortened. But any influence could not be seen in other 2 varieties. While its period under the comparatively warm night was enlarged for all varieties at the different degree. 3. Flowering of soybeans under the short day was accelerated as compared with that of control and the acceleration ratio gradually increased with going to late varieties. Flowering of soybeans under the long day was retarded and the degree was increased generally with going to late varieties. Any flower did not bloom in Morse especially under the long day. Flowering period of Morse was enlarged by the short day, but its period of other varieties was shortened. 4. Flowering was far greatly accelerated by the short day treatment than the warm temperature treatment. The acceleration ratio by the warm temperature treatment has any relation to the late or early habit of varieties. While the response for light is thought to be strengthened with going to late varieties.
