Abstract
A recently released rice cultivar 'Meguriai' was suggested to have higher grain filling ability. To evaluate the grain filling characteristics of Meguriai, its filled grain percentage, grain filling process, and other related characters were examined under both control and defoliating plots. Meguriai showed higher filled grain percentage, higher grain-filling rate, and higher final grain weight, in the grain on secondary branches, compared with Norin 22, a parent from which Meguriai was developed. Norin 22 showed the re-accumulation of non-structural carbohydrates in leaf sheath and culm at the period from 20 to 30 days after heading. Meguriai, on the other hand, did not show this reaccumulation. It was suggested that the grain of Meguriai, particularly for the grain on secondary branches, had higher sink activity to attract photosynthates, and resulted in higher filled grain percentage of the grain on secondary branches.
