Abstract
To study the variation of yield-component characters and yield according to the different spacing of rice plant, with relation to years in the northern Japan, the experiment were carried out during the three years from 1954 to 1956. The thickly spaced culture of rice plant suppressed individual growth ever since earlier stage, but was more favorable for obtaining many ears, spikelets and yield per unit area than thinly spaced culture. The yield-component characters per unit area increased in proportion to the planting density, showing a straight line, throughout three years. As the tendency seems to be modified by various conditions, we intend to clarify how the modification takes place by the combination of conditions in the future experiment.
