Abstract

1. Six day-neutral rice varieties were sown at one week intervals throughout the year in three different regions of Taiwan. The temperature during the whole year and the growth duration of each planting were recorded. 2. There was negative correlation between growth duration and temperature for all the varieties. The optimum temperature for growth 27.89±0.71 C Little variation existed among the three experimental locations. 3. The growth duration under optimum temperature varied among the varieties. It is suggested that the minimum length of growth duration under optimum temperatire be considered as the basic growth duration for each variety. 4. The temperature coefficient (Q10) between 19 C and optimum temperature (ca. 28 C ) averaged 3.5-1.2. so in rice , Q10 is also high at low temperature and low at high temperature.