Analysis of Heat Stress Tolerance in Seeds of Rice Cultivar “Hitomebore” under Treatment of Hot Water Disinfection Method

Abstract

Hot water disinfection of rice seeds has recently received increased attention as a clean farming technique, because it does not produce waste fluid including harmful chemical compounds. However, the seeds of several rice cultivars are sensitive to heat-shock and could not germinate after disinfection by this method. In addition, some diseases cannot be controlled efficiently by hot water disinfection method. In order to spread this disinfection method, it is necessary to introduce a trait of heat stress tolerance into the seeds of many rice cultivars. For this reason, it is important to find strains whose seeds are tolerant to heat, and to understand the mechanism of the tolerance. The present work showed that the seeds of cultivar “Hitomebore” are more tolerant to a high temperature than “Nipponbare”. Moreover, the results of experiments using seeds with and without hulls revealed that the heat stress tolerance of “Hitomebore” seed is attributed to the features in both hull and brown rice.