Factors Affecting Variance in Yield Caused by Different Transplanting Times in High-Yield and Good-Eating-Quality Rice

• Published in: Japanese Journal of Crop Science Vol. 91; no. 2; pp. 129 - 135
• Main Authors: Yoshinaga, Satoshi, Yabe, Shiori, Ogiwara, Hitoshi, Kobayashi, Nobuya, Okamura, Masaki, Arai-Sanoh, Yumiko
• Format: Journal Article
• Language: Japanese
• Published: Tokyo CROP SCIENCE SOCIETY OF JAPAN 05.04.2022; Japan Science and Technology Agency
• Subjects: Climatic conditions; Crop diversification; Crop yield; Cultivars; Eating quality; Oryza sativa; Quadratic equations; Radiation; Rice; Shoot dry weight; Sink capacity; Solar radiation; Transplanting time; Yield
• ISSN: 0011-1848; 1349-0990
• DOI: 10.1626/jcs.91.129

To avoid farm work competition and explore the possibility of diversification of cropping, we evaluated the yield and yield characteristics of the transplanting times (early, middle and late) in rice (Oryza sativa L.) for three years using three high-yielding cultivars, “Akidawara”, “Yamadawara” and “Toyomeki”, which have high eating quality. The later the transplanting time, the lower the filled brown rice yield. Sink capacity and the increase in shoot dry weight during grain filling tended to be smaller the later the transplanting time. To reveal the factors lowering the yield in late transplanting, we carried out several analyses under various climate conditions. The relationship between Y/S value, obtained from dividing yield (Y, g m–2) by cumulative solar radiation (S, MJ m–2) from 30 days before heading to 20 days after heading, and the average daily temperature in the same periods were approximated by a quadratic equation, meaning yield could be explained well by temperature and solar radiation. The maximum value in Y/S was found at around 23.4 to 24.0 ºC. On the other hand, it was inferred that the lower yield in late transplanting was affected not by the average daily temperature before and after heading but by the lower average daily solar radiation.