抄録
Field experiments were carried out from 1966 to 1972 using rice varieties "Hoyoku'' and "Shiranui" both in normal season culture and early planting culture to find out relationship between yield or yield components and climatic factors or other factors. Results obtained are as follows. 1. Mean temperature for 3 weeks from heading did not show significant simple correlation with yield, but, it showed significant negative partial correlation with yield. It suggests that yield tends to decrease with increase of the mean temperature of that period, when excluding the effect of other factors. 2. High negative correlation was found between mean temperature for 3 weeks from heading and 1000 kernel weight, and it was supposed that this fact corresponded to the significant negative partial correlation found between yield and the mean temperature for 3 weeks from heading. 3. Positive correlation was found between number of ears per m2 and ratio of solar radiation to mean temperature during the period from transplanting time to 6 weeks before heading, showing that abundant solar radiation and low temperature in tillering stage was apt to produce a large number of ears. 4. Positive correlation was found between spiklet number per m2 and solar radiation during the period 6 weeks before heading, and negative partial correlation was found between spiklet number per m2 and mean temperature during the same period. 5. Negative correlation was found between 1000 kernel weight and calculated value of respiration after heading.
