Abstract
This Study was attemped to get a clue available for the improvement in the activity of photosynthesis of soybean varieties. The result are as follows: 1. Frequency of occurrence of improved varieties showing the high photosynthetic rate increased in the cases of combinations with the parent varieties of high photosynthetic activity. 2. Most of the improved varieties were selected so that their photosynthetic rates became practically as high as, or higher than those of their parent varieties having the high activity of photosynthesis. 3. By means of breading tecniques, it would become possible to increase the photosynthetic rates of soybean varieties appeciably higher than the present level. It is deemed possible enough to raise the photosynthetic rates, at least, of Kanto-Tosan soybean variety group in Japan.
