抄録
The effects of warm water during vegetative growth on cold tolerance for sterility induced by low temperatures at the booting stage were investigated in a field experiment. In an experiment in Aomori Pref. and Miyagi Pref., four rice cultivars were grown under two water temperature conditions (control and warmer than control by 2.2 or 3.7°C) during vegetative growth over a short period of time (21 days after transplanting for 21-27 days), and tested for their cold tolerance. Warm water promoted the heading date up to four days and it did not affect the number of spikelets. Cool-water treatment induced spikelet sterility in the range of 84-95% in Aomori Pref. and 54-90% in Miyagi Pref., while warm water applied during vegetative growth decreased the spikelet sterility of all cultivars and in both locations by 2-11 percentage points in Aomori Pref. and by 2-25 percentage points in Miyagi Pref. The results indicate that applying warm water during vegetative growth over short periods of time can improve cold tolerance in rice in the field.
