Abstract
To forecast the effect of increase in temperature on the variation in rice yield, the relationship between climatic factors and rice yield must be quantitatively examined. This research estimates the effect of temperature increase (daily mean temperature increase 1-3℃) on two important factors at five locations (different in altitude) in Shimane Prefecture. First, heading date is estimated by the model of Nakagawa et al. Second, potential ripening ability is estimated from the data of temperature and sunshine hour in ripening stage, using the model of Munakata et al. Increase in daily mean temperature by 3℃ forwards heading date of Kosihikari by 13-18 days. In this situation, Kosihikari yield will decrease more than 15% because temperature in ripening stage increase and heading date is hastened. Increase in daily mean temperature by 3℃ delays optimum full heading date which maximizes climatic productivity of rice by more than 11 days. At that time yield decrease in Matue is 6% and that in Akana (higher location) is 13%.
