Abstract
A further experiment was conducted on the influence of temperature and shading on the development of rice panicle. The variety, Rikuu No. 132, was treated with all combinations of temperatures (17, 21 and 25°C), shading grades (70 % shading and non-shading) and durations (6 and 10 days) immediately before the "booting" stage. The 17°C treatments decreased the number of spikelets per panicle rather conspicuously, and also decreased markedly the percentage of fertile grains and filled (not empty) pollens. The shading treatments also brought about a corresponding decrease in the number of spikelets per panicle at the 21 and 25°C treatments, the decrease being influenced by the higher temperature. These shading treatments had no effect at the 17°C on the decrease of spikelet number. Further, the shading treatments did not affect the percentage of fertile grains and filled pollens.
