The Korean Journal of Crop Science ISSN:0252-9777(Print) 2287-8432(Online) 한국작물학회지

This study aimed to analyze the optimal transplanting date of the floury endosperm rice varieties Hangaru, Seolgeang, Singil, and Baromi2 allowing to reduce the viviparity rate. The viviparity rate rapidly increased with the mean temperature during the ripening stage. Therefore, to reduce the viviparity rate, we calculated the optimum heading date based on the safe heading date limit in each area so that the ripening stage occurred at lower temperatures. hen, the effects of changes in heading date were monitored by recording the transplanting date and the temperature during the growth period. The transplanting date was highly correlated with the number of heading days in the field. Therefore, the optimum transplanting date was calculated according to the transplanting date in each area. When the accumulated temperature was 700°C, if floury rice was transplanted at the optimum transplanting date, the mean temperature was approximately 20°C. When the accumulated temperature was 900°C, the mean temperature was approximately 18°C. Under these conditions, the viviparity rates of Hangaru, Seolgeang, and Singil rice were lower than 10%. However, Baromi2 showed a high viviparity rate. These results suggest that the viviparity rate of Hangaru, Seolgeang, and Singil rice can be reduced by transplanting at the optimum transplanting date. However, further research is required for pinpointing the optimum transplanting date of Baromi2 rice.