2023 Volume 92 Issue 2 Pages 184-189
Although new rice varieties that are resistant to high-temperature damage during rice grain ripening are being cultivated, the time and effort required to create new varieties is a burden. The objective of this study was to establish a method for selecting rice varieties with tolerance to high temperatures at the rice grain ripening stage focusing on the differences in growth responses to high temperature treatments at the seedling stage between varieties bred to be tolerant to high-temperature damage during the rice grain ripening stage and existing varieties. The plants after germination were grown hydroponically in growth chambers for 14 days under daytime and nighttime temperatures of 25°C and 20°C, respectively, in the control and 35°C and 30°C, respectively, in the high-temperature treatment. Compared to the varieties cultivated as resistant varieties, the growth of existing varieties was slow in the control, but this difference was eliminated by the enhanced growth in the high-temperature treatment. The difference in growth between the high-temperature treatment and control was significantly smaller in the varieties cultivated as resistant varieties than in the existing varieties. From these results, it was considered possible to select varieties with resistance to high-temperature damage during the rice grain ripening stage by selecting varieties showing less difference in the growth of the shoot or the root in the high-temperature treatment as compared to the control at the seedling stage.
