Abstract
The purpose of this experiment was to investigate the effects of temperature during the vegetative growth stage and the reproductive stage on the growth and yield of rice plant under the condition of controlled environment. Results obtained are summarized as follows : 1) It was reaffirmed that the factor affecting the ripening or rice plant was not only the environmental conditions during the ripening stage but the environmental conditions during the vegetative growth period also played an important role in the ripening of the grains. 2) It seemed that the ripening was controled mainly by the temperature during the reproductive period in the cultivars adapted to the cold districts, and the temperature during the vegetative growth period, however was more important in the cultivars adapted to the warm districts for the ripening of the grains. 3) Influences of the temperature during the vegetative growth period on grain ripening and yield was very slight due to the shorter period of the vegetative growth stage. The significant effect of temperature during the vegetative growth stage, on the other hand, was found in the cultivars adapted to the warm districts of Japan. which had the lower thermosensitivity and the longer vegetative growth period.
