2023 Volume 92 Issue 2 Pages 140-152
To stabilize the production of Tamba-Dainagon Adzuki bean, a local specialty crop in Kyoto Prefecture highly valued by consumers, it is necessary to accumulate knowledge on the environmental response of adzuki bean to changes in climate and soil moisture. In this study, we examined the effects of soil drought on the growth and yield of the adzuki bean variety 'Kyoto-Dainagon' at different times from pre-flowering to post-flowering. Soil drought lowered the photosynthetic rate, and decreased the main stem length and node number. Soil drought around the flowering period reduced the number of pods and bean weight, resulting in a decrease in yield. On the other hand, the photosynthetic rate increased after the reduction of soil drought. The reduction of soil drought during the pre- and post-flowering periods was accompanied by an increase in photosynthetic rate, leading to an increase in bean weight. In addition, delayed leaf senescence was observed in adzuki bean that were under a wet condition after the soil had dried out. This is thought to be caused by the excess source of photosynthesis by pod reduction and/or development of root systems under drought due to the recovery of photosynthetic rate under the wet conditions. Thus, it is clear that the yield is reduced and leaf senescence is delayed by soil drought in adzuki bean.
