Abstract
We examined how elongation characteristics of coleoptiles and sugar contents of seeds affect the seedling emergence and establishment of rice direct seeded in a flooded paddy field using 30 rice cultivars. Here, we examined the correlation of seedling emergence and establishment of rice, which was seeded after germination under drained conditions in containers with the elongation characteristics of coleoptiles and sugar content of seeds under anaerobic conditions. In the container experiments, rapid emergence of the coleoptiles, first leaves and second leaves increased the final percentage of emerged and established seedlings. Under anaerobic conditions, the earlier the elongation of coleoptiles the longer the final length of coleoptiles and the length of coleoptiles was positively correlated with the amounts of glucose in embryos and endosperm. Since the length of coleoptiles under anaerobic conditions was positively correlated with the final percentage of emerged seedlings in container experiments, the length of coleoptiles under anaerobic conditions was considered to be useful as an index for selecting cultivars suitable for direct seeding in a flooded paddy field.
