Abstract:Based on field experiments, statistical analysis and modelling were carried out to investigate the changes of climatic resources utilization, risk of heat and chilling stress as well as suitable varieties and sowing date for single season rice to switch from indica to japonica type in Hubei Province. The results showed that changing rice from indica to japonica type can improve resource efficiency of climate, and reduce the risk of chilling injury during heading period, but increase heat stress. Among five tested cultivars, Yongyou1540 (indica japonica hybrid) shows the best suitability across all ecological regions, while the performance of Rejingyou35 and Zhongdao1 is less satisfactory or with less suitability than Yongyou varieties. It is concluded that rice of japonica type should be sowed in the last ten day period of April in the northern part of Hubei, and in the early and middle May in the southern part. Sowing in this window, 80% of the years could avoid heat stress during heading period.