Analytical studies on the stability of the factors affecting the appearance of the grain and eating quality in rice [Oryza sativa], 2: Effects of low planting density on the dry matter production, yield and grain appearance
2004
Inoue, K. (Fukui-ken. Agricultural Experiment Station (Japan)) | Hayashi, T. | Yuasa, K. | Oida, T.
Summary Growth and dry matter production characteristics along with grain yield and qualities were studied for four years under different planting density conditions on the rice cultivars Koshihikari and Hanaechizen with the goal of stable rice production. In sparse planting density conditions in Koshihikari, the crop growth and dry matter production were lower than normal or high planting density in the early growth stage. But the crop growth rate became higher after the heading stage. And the nitrogen content of the leaf blade was maintained a higher level during the ripening period. The grain growth rate in the former ripening period was lower in sparse planting density. On the other hand, that in the latter ripening period was higher. The grain yield was almost the same in planting density 14 hills per square meter as normal 21 hills per square meter in both cultivars, because the dry weight at maturity and the number of spikelets per square meter were similar in both densities. In sparse planting density, the decrease of yield and grain appearance was lower under shading treatment during the former ripening period, and with 10 days early application of topdressing, the increase of the lodging index was lower and the yield became higher. In Koshihikari, the appearance of the grain was improved by the sparse planting density treatments because the percentage of perfect grain increased and the percentage of milky grain decreased. Also in Hanaechizen, the percentage of white back grain and white base grain decreased with the sparse density treatments. These results shows that maintaining high ripening ability through higher nitrogen content in the leaf blade is effective enough for high quality grain production.
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