2017 Volume 86 Issue 3 Pages 229-235
Increase in production of whole crop rice silage is expected to improve the food self-sufficiency rate in Japan. Introduction of forage rice cultivation under late seeding conditions into the rice-wheat cropping systems is considered a means of cultivation management for high land use efficiency, high productivity, and reduction in cost and labor. It is crucial for improvement of forage digestibility to accumulate non-structural carbohydrate (NSC) in stems rather than in panicles. Furthermore, direct seeding could increase lodging risk. Therefore, we examined the differences in NSC accumulation in stems and lodging resistance among eight cultivars under late direct seeding conditions for two years in Western Japan. Cultivars with a small panicle ratio to the whole aboveground biomass, could accumulate a large amount of NSC in the stems due to the reduction of accumulation of assimilates in panicles during the yellow ripening stage. Meanwhile, these cultivars had a longer yellow ripening stage, and their growth overlapped with the beginning of the winter crop (wheat) season. In some cultivars, however, the NSC concentration in stems could be increased by harvesting at the dough ripening stage. Furthermore, the panicle ratio to the whole aboveground biomass was small at the dough ripening stage resulting in a superior lodging resistance.
