Growth of broadcasted rice [Oryza sativa] and compensatory effect on yeild at different seedling densities
1998
Ehara, H. (Mie Univ., Tsu (Japan). Faculty of Bioresources) | Morita, O. | Kaneko, T. | Fujiyama, G.
A field trial was conducted to analyze the growth characteristics and compensatory effect on the yield of rice (cv. Yamahikari) broadcasted in submerged soil at four levels of seedling density (32, 64, 96, 160/square meter). The relative tillering rate (RTR) and relative growth rate (RGR) were greater in higher density plots (86, 160/square meter) in the early growth stage and greater at lower seedling densities in the subsequent growth stage. The difference in RGR was mainly attributed to leaf area ratio (LAR) in the early growth stage and net assimilation rate (NAR) in the subsequent stage. A difference in specific leaf area was observed during the growth period, which was responsible for the differences in LAR and NAR at 58-79 days after sowing (DAS). Although there were distinctive differences in yield components, the changing patterns of which to seedling density were not similar. There was no significant difference in yield per square meter among seedling densities. The lower density plots (32, 64/square meter) showed high RTR through high NAR in the middle and late growth stages, and the panicle number per plant was greater at lower seedling densities. This was the first response for compensatory effect. The spikelet number per panicle increased when panicle number per square meter decreased with the decrease in seedling density, which was also an important factor on the compensatory effect. Here, a positive correlation was found between spikelet number per panic
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