The Effect of Lodging on the Seed Yield and the Yield Components of Italian Ryegrass(Lolium multiflorum Lam.)

[摘要] The effect of lodging on the seed yield and the yield components of four cultivars of Italian ryegrass, including two early varieties, VVaseyutaka and Wasehikari and two late ones, Yamaaoba and Nasuhikari was studied in a field trial. To this purpose each variety was given four lodging treatments: natural control (lodged naturally), no lodging (supported mechanically), and artificial lodging at early anthesis (the beginning of anthesis) and at late anthesis (9 to 12 days after the beginning of anthesis). Varietal difference was recognized in the degree of lodging, showing greater differences between the early varieties and between the late ones than between the early and the late ones. In all varieties, the increase in the seed yield was significantly higher by supporting the plant than by any other lodging treatments. The rate ofincrease in the seed yield by supporting the plant was greater in the late variety, but had no relation to the degree of lodging. When compared with the supported plant, the reduction in the seed yield due to lodging at early anthesis was 33to 36%, showing no varietal difference and at late anthesis 9 to 18%, showing a significant varietal difference. The increase in the number of ears was brought about by supporting the plant in the late varieties but not in the early ones. The reduction in the number of ears due to lodging at early anthesis was greater in the late varieties, being 28%, than in the early varieties, being 16%, and the reduction at late anthesis was smaller than at early anthesis. In all varieties, higher seed weight per ear was produced by preventing the plant from lodging. According to this, the increase in the seed yield due to prevention of lodging was recognized to be brought about by the increase in the seed weight per ear in early varieties and by both the seed weight per ear and the number of ears in late ones. The reduction in the seed yield by lodging was found to have relation to decrease in the seed weight per ear in the early varieties and in the number of ears in late ones.

[学科分类] 农业科学（综合）