2006 Fiscal Year Final Research Report Summary
Modeling and Prediction of the Occurrence of Chalky Grains in Rice
| Project/Area Number |
16380019
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Crop science/Weed science
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| Research Institution | Ishikawa Prefectural University (2005-2006)
Ishikawa Agricultural College (2004) |
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Principal Investigator |
NAKAGAWA Hiroshi Ishikawa Prefectural University, Faculty of Bioresources and Environmental Sciences, Associate Professor, 生物資源環境学部, 助教授 (90207738)
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| Co-Investigator(Kenkyū-buntansha) |
KANO Yasutaka Ishikawa Prefectural University, Faculty of Bioresources and Environmental Sciences, Professor, 生物資源環境学部, 教授 (80115823)
SUZUKI Shoichi Ishikawa Prefectural University, Faculty of Bioresources and Environmental Sciences, Professor, 生物資源環境学部, 教授 (20162951)
NAGAHATA Hideki Ishikawa Prefectural University, Faculty of Bioresources and Environmental Sciences, Research Instructor, 生物資源環境学部, 助手 (80405068)
TSUKAGUCHI Tadashi Ishikawa Prefectural University, Faculty of Bioresouroas and Environmental Sciences, Lecturer, 生物資源環境学部, 講師 (40345492)
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| Project Period (FY) |
2004 – 2006
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| Keywords | rice / high temperature / visual quality / chalky grain / milky white grain / model / simulation / white-based and white-belly grains |
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| Research Abstract |
Reported data were collected on the occurrence of chalky grains in rice production in Hokuriku Area and analyzed to reveal that the percentage of chalky grain increases with an increase in temperature and agricultural practices and the types of chalky grains affect the temperature responses.
Clipping treatments of leaf blades and panicles, a thinning treatment were given to field grown rice (cv. Koshihikari and Hatsubosi) in order to alter the amount of assimilate supply per one grain (ASPG). ASPG affected the occurrence of milky white grain, but not white-belly and white-based grains. An increase of 1 mg in ASPG reduced the percentage of milky white grain by 1%. Nitrogen topdressing at the full heading stage decreased the percentage of milky white, white-belly and white-based grains. High temperature treatments at various stages during the grain-filling phase with varied durations were given to potted rice plants (cv. Koshihikari), of which leaf blades and panicles were clipped at the full heading stage to alter ASPG.
Based on those experimental data, we have developed a simple model to predict the percentage of milky white grain. The model uses an accumulated temperature concept with some modifications and includes the effects of ASPG. Our model well explained the occurrence of milky white grains in rice grown under various conditions. We estimated the best cropping seasons and the optimum grain numbers for rice crops in Kanazawa, Wajima, Toyama and Fukui by simulations with our model.
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