Abstract
Seedling emergence following direct seeding in a flooded paddy field at a low temperature was measured. Germination characteristics under aerobic conditions and coleoptile elongation under anaerobic conditions associated with seedling emergence were assessed. The rice cultivars used were 21 high eating quality rice cultivars from Hokkaido, Tohoku, and Hokuriku districts, and Etsunan 242, which has high eating quality and good seedling emergence. The speed of seedling emergence was positively correlated with the final seedling emergence rate. The speed of germination and the germination coefficient were not correlated with the speed of seedling emergence, suggesting that germination characteristics were not related to seedling emergence. The speed of coleoptile elongation, speed of seedling emergence, and final seedling establishment rate were higher in Etsunan 242 than in other rice cultivars with high eating quality. The speed of seedling emergence, final seedling emergence rate, final seedling establishment rate, and dry weight of above-ground plant parts were highest in the cultivars from Hokkaido followed by Tohoku and Hokuriku in this order.
