Abstract
1. Soybean seeds of 18 varieties in 1949 and 15 varieties in 1950 preserved at Odate Agricultural Improvement Experiment Station of Ministry of Agriculture and Forestry were sown several times in the field at that station consisted of volcanic ash soil and the plants were cultivated customarily. 2. Number of days from sowing to flowering date decreased gradually with late sowing and by the warmer climate. But there is not any relation between the shortening ratio and the earliness or lateness of flowering were placed in the vigorous responsive varietal group upon temperature and the reverse varieties were included in the weak responsive varietal group upon temperature. Odate No. 1 and Yogetsu belong to the latter group. 3. Flowering period generally decreased gradually with late sowing. But the flowering period of Pinpu sown July was longer than the case of May. 4. Correlation coefficient between number of days from sowing to flowering date and flowering period is 0.391. Varieties of long flowering period have vigorous trailing habit.
