Abstract
The response to temperature of the flowering time in rice plants has been studied in order to determine the favourable range of temperature and the lower limit of that. Seedlings of various rice varieties were grown in a phytotron with different temperatures for 14 to 21 days. Varietal responses of flowering time were investigated with different treatnents of temperature to a certain stage of seedlings. (1) Within the range of 30.0-18.6°C, the differences of flowering times between treatments were small in all varieties and this range was considered to be favourable for accelerating flowering time. (2) Between treatments including the range of 18.6-17.5°C, the differences of flowring times of all varieties were large at ear-differentiating stage, though they were small in early growing stage of plants. From this result, the lower limit of the favourable temperature was considered to lie between 17.5 to 18.6°C for all varieties. (3) The temperature lower than 17.5°C appeared to be out of favourable temperature, because the differences of flowering times between the 17.5°C and 13.2°C treatments were also small.
