Effects of Hot Water Disinfection and Cold Water Seed Soaking on Germination in Feed Rice Varieties of Tohoku Region.

Abstract

Low percentage of germination and emergence has been a serious problem in cultivation of feed rice varieties in the Tohoku region of Japan. In order to elucidate the factors causing low percentage of germination, we investigated the effects of hot water disinfection and cold water seed soaking on germination using 20 rice varieties including feed rice varieties of Tohoku region. Hot water disinfection for a long time (60°C, 30 minutes) decreased the germination percentage more in feed rice varieties, glutinous rice varieties, and indica type varieties than in food rice varieties. Among the feed rice varieties in the Tohoku region, “Bekogonomi”, “Bekoaoba”, “Iwaidawara”, “Ushiyutaka” and “Yumeaoba” showed a lower germination percentage. The rice seed after sprouting treatment showed the low germination percentage after hot water disinfection, suggesting that the germination rate of feed rice varieties with weak sprouting resistance tends to decrease the percentage of germination after hot water disinfection. Seed soaking at 5°C decreased the germination percentage in some feed rice varieties in the Tohoku region, although soaking at 12°C did not. These results suggest that hot water disinfection for a long time and soaking in very cold water tended to decrease the getmination percentage in some feed rice varieties in the Tohoku region.