The Effect of High-Temperature Stress Applied to the Root on Grain Quality of Rice

We verified the effect of high-temperature stress applied to the root on the occurrence of white immature kernels (WIKs) in order to breed rice (Oryza sativa L.) cultivars tolerant to the high temperature during the ripening period. The plants were grown in control and warmed pools after the heading date. The WIK percentages in the warmed pool were higher than those in the control pool. This suggests that high-temperature stress applied to the root increases the occurrence of WIKs. On the other hand, the WIK percentages correlated positively and significantly with the 1000 kernel weight and kernel width, suggesting that rice cultivars with high-temperature tolerance might have a smaller and/or thinner grain