水稲

This experiment was carried out to clarify the extent of damage caused by stormy wind to the heading stage and milky ripening stage of rice plant. Special importance was given to the point of determining the conditions which bring about discoloration and sterility of rice panicles, that is, both the condition of the wind flow and the growing condition of rice. Moreover investigations were carried out on the grades of coloration of panicles, weight of panicles and percentage of sterility. The storm was created artificially by the wind tunnel installed at the phytotoron of Kyushu University. Storm treatment was done for three hours continuously by blowing wind artificially. The speed of the wind was 20 m per sec. and the relative humidity ranged from 40 per cent to 97 per cent. The results obtained were as follows; 1. Discoloration of panicles was observed only when the humidity of wind was below 70 per cent. 2. Discoloration of panicles was specially observed when the roots were damaged due to presence of H_2S in the ground and the rice plant was grown under excessive nitrogen supply. 3. When the humidity of wind was high, brown spots and blackish coloration were observed on the panicles, and when the humidity was low discoloration and black coloration of the panicles were resulted. 4. Under high humid condition of the wind the weight of panicles reduced a little but under low humid condition the weight reduced remarkably. 5. At the heading stage the reduction of panicle weight was due to high percentage of sterility and at the ripening stage it was due to lesser weight of 1000 grains.