Effects of Planting Density on Spikelet Number in Tachiayaka, a Rice (Oryza sativa L.) Cultivar with a Short Panicle

• Published in: Japanese Journal of Crop Science Vol. 88; no. 4; pp. 253 - 258
• Main Authors: Matsushita, Kei, Nagaoka, Ichiro, Sasahara, Hideki, Maeda, Hideo, Watanabe, Hajime
• Format: Journal Article
• Language: Japanese
• Published: Tokyo CROP SCIENCE SOCIETY OF JAPAN 05.10.2019; Japan Science and Technology Agency
• Subjects: Crop yield; Cultivars; Cultivation; Fertilization; Hills; Nitrogen; Planting; Planting density; Propagation; Rice; Seed production; Seeds; Short panicle; Spikelet number; Tachiayaka; Transplantation; Whole-crop silage; Yield component
• ISSN: 0011-1848; 1349-0990
• DOI: 10.1626/jcs.88.253

Rice cultivars ‘Tachiayaka’ and ‘Tachisuzuka’, which have short panicles, were developed for whole-crop silage use because of their improved feed value owing to their decreased numbers of hard-to-digest spikelets. However, these cultivars do not produce a sufficient number of seeds for propagation. Nitrogen application at the panicle-formation stage, low planting density and late transplantation improve the unhulled rice yield in ‘Tachisuzuka’, and similar nitrogen application also improve seed production in ‘Tachiayaka’. However, changes in cultivation methods other than fertilization have not been investigated in ‘Tachiayaka’. Therefore, the effects of the planting density on the yield components of ‘Tachiayaka’ were studied from 2014 to 2016. With an increase in planting density, the panicle number increased; however, the number of spikelets per panicle decreased. Thus, the spikelet number per unit area was not significantly affected by the planting density. In addition, there were more late-emerging panicles in 5.6 hills m–2 or 7.4 hills m–2 than in 11.1 hills m–2, indicating that an extreme low density is unsuitable.