Cross-tolerance to Thermal Stresses and its Application to the Development of Cold Tolerant Rice

Having originated in tropical regions, rice is more sensitive to cold stress than other grain crops, such as rye, wheat, and barley, which originated in temperate regions. Despite the limited knowledge about the exact mechanisms of cold tolerance, breeders have generated new rice cultivars that can grow in Hok-kaido, Japan's northern limit of rice cultivation, for more than a hundred years. However, greater cold tolerance in rice would enable more stable production and elevate productivity. Because cold tolerance is a complex quantitative trait, it is difficult to pyramid the genes that could improve plant tolerance to this abiotic stress. Therefore, it is important to develop effective strategies for improving cold tolerance in rice. In this review, the use of a 'cross-tolerance' strategy is proposed, and the current status of such strategy introduced.