Effects of Drying and Temperature During Storage of Rice Seeds Coated with an Oxygen Supplier on the Seedling Emergence

In submerged direct-seeding rice (Oryza sativa L.) cultivation, it is important to stabilize the emergence of seedlings. We examined the effects of drying and temperature during storage of rice seeds coated with an oxygen supplier on the seedling emergence. The seedling emergence rate was not affected by the storage at 10°C for 3 days. However, the emergence of seedlings was stimulated by 3-day storage at 15-30°C, and the stimulation was especially clear at 20 and 25°C. In the seeds which ware not dried or excessively dried after the seed coating, the stimulation of seedling emergence in spite of a 3-day storage at 20 or 25°C was less evident than in the seeds which ware dried to lose 2 to 5% weight after coating. The stimulatory effect of the 3-day storage at 20-25°C was observed in all rice cultivars examined irrespective of the method of water management after seeding. Since thiss stimulatory effect was not reduced by a subsequent 7-day storage at 10°C, the seeds with high emergence ware considered to have retained the high emergence ability due to the storage for a long period at a low temperature.