| Project/Area Number |
11660018
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
作物学
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| Research Institution | Kochi University |
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Principal Investigator |
YAMAMOTO Yoshinori Kochi University, Faculty of Agriculture, Professor, 農学部, 教授 (00093956)
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| Co-Investigator(Kenkyū-buntansha) |
MIYAZAKI Akira Kochi University, Faculty of Agriculture, Assistant, 農学部, 助手 (00304668)
YOSHIDA Tetsushi Kochi University, Faculty of Agriculture, Professor, 農学部, 教授 (10145112)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2001: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2000: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1999: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Keywords | Degenerated spikelet / Differentiated spikelet / Environmental factors / Grain filling / Large panicle cultivar / Rice / Sink capacity / Surviving spikelet / 溢泌液 / 穎花 / 国際研究者交流 / 遮光 / ジベレリー / 品種 / 乾物重 / 窒素吸収量 / 頴花分化 / 頴花退化 / 窒素追肥 / リン酸追肥 |
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| Research Abstract |
This study was conducted to clarify the characteristics of the differentiation and degeneration of spikelets and the grain-filling in high-yielding rice cultivars with large panicles (LP-HYC) bred in China, Korea, the Philippines and other countries in recent years. The results were summarized as follows ;
1. The number of differentiated and degenerated spikelets, and the percentage of degenerated spikelets varied considerably among LP-HYCs, but the number of degenerated spikelets was much larger in the differentiated spikelets on the secondary rachis-branch (SB) than those on the primary rachis-branch of panicle (PB). The major part of degenerated spikelets on SB was derived from the degenerated SBs on the surviving PB.
2. Nitrogen top-dressing at tillering stage to LP-HYCs increased the number of differentiated spikelets per panicle as well as the panicle number, but greater increase in the percentage of degenerated spikelets at the same time decreased the number of surviving spikelets.
3. Nitrogen, phosphorous and potassium application at 40-20days before heading increased the number of surviving spikelets due to the increase in differentiation and the decrease in degeneration of spikelets in LP-HYCs. The heavy shading and high-day and/or night temperature during 15 days before heading increased the percentage of degenerated spikelets. The percentage of degenerated spikelets decreased with the increase of shoot dry weight per stem (SDW) and SDW per differentiated spikelets at heading.
4. Contribution ratio of the stored carbohydrate in the culm and leaf sheath at heading and the assimilated carbohydrate after heading to the grain-filling varied so much among cultivars belonging to LP-HYC and by the cultivated conditions.
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