REVIEW Ecophysiological Analysis on Effect of Planting Pattern on Biomass Production and Grain Yield

Increasing the biomass productivity of rice is a critical research target for improving the yield potential. This paper reviews ecophysiological studies on biomass production as affected by agronomic techniques and cultivars. In addition, we examined the effects of the planting pattern on the biomass production using cv. Takanari, a high-yielding and lodging resistant cultivar. The results showed that greater bio-mass production and grain yield were observed in plants with the combination of one plant per hill, high hill density and square hill arrangement. The factors responsible for high biomass production in this combination are; (1) vigorous tiller increase at the tillering stage resulting in higher capture of solar radi-ation, (2) erect leaves in the canopy after the panicle formation stage resulting in an improved light-inter-cepting character or smaller extinction coefficient, and (3) larger nitrogen accumulation during the ripening period resulting in a smaller decline of photosynthesis as well as a smaller midday and after-noon depression of photosynthesis possibly related to the larger water uptake ability of roots owing to better root-system development. Our results implied that an improvement in biomass production and yield is possible by optimizing the planting pattern and nitrogen management using high-yielding and lodging resistant cultivars in transplanted and direct-sown rice. Discipline: Crop production Additional key words: light extinction coefficient, light interception, photosynthesi