Studies on Yield-Forecast in Main Crops : X. A characteristic in grain production of rice plant in Chugoku district

The study was carried out to make clear the process of grain production of rice plant in Chugoku district using the data of the experiments performed at several experiment stations in Chugoku district year by year from 1948 to 1959 under the same cultural condition. The results obtained are summarized as follows : It was concluded that in usual rice culture in Chugoku district, (1) the yield is associated with the number of spikelets per unit area, (2) the number of spikelets per unit area depends mainly on the number of panicles, (3) the number of panicles is closely related to the number of tillers produced, and (4) the number of tillers varies with air temperature and light intensity at the middle of July. Therefore, the number of spikelets per unit area was thought to be an important index in the yield-forecast of rice plant in Chugoku district.