1999 Fiscal Year Final Research Report Summary
Comparative studies on crop root response to rheological traits in soil.
| Project/Area Number |
09660011
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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 | Shinshu University |
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Principal Investigator |
INOUE Naoto Shinshu Univ., Associate Prof., 農学部, 助教授 (80232544)
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| Co-Investigator(Kenkyū-buntansha) |
HAGIWARA Motoyuki Shinshu Univ., Associate Prof., 農学部, 助教授 (90172840)
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| Project Period (FY) |
1997 – 1999
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| Keywords | root / rice / soil / direct seeding / establishment / rheology / viscocity / circumnutation |
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| Research Abstract |
Field experiments were carried Out to clarify the differences and key factors in the rate of seedling establishment among rice varieties sown on the soil surface in flooded paddy fields. There is a significant difference among varieties. The main causes for lower seedling establishment rate existed in floating and seedling mortality in the younger stage. These two causes were independent of each other. No clear correlation were found between the percentage of floating seedling and the plant length, the seminal root length or the apparent weight of seedling in water, which has been reported to be the cause of floating seedlings resulting in poor seedling establishment. Root tip rotation was analyzed for indoor-grown seedlings using spectrum analysis: the maximum entropy method (MEM) was used. MEM spectrum analysis clarified that maximum power density detected in the frequency range above 0.1 cycles mmィイD1-1ィエD1 was highly and positively correlated to seedling establishment percentage in the field experiment. From the result, root tip rotation with a larger spiral angle was suggested to play an important role in the establishment of rice seedlings on flooded and very soft soil. The percentage of the seedlings with a spiral root growth with a larger angle was examined on a medium with low viscosity (10-20cp) by using 76 varieties obtained from IRRI Core Collection. The percentage is a convenient and useful method for screening rice varieties with high seedling establishment rate. The higher the viscosity of seedbed is, the higher the frequency of spiral per unit root length in the case of varieties which have a higher ability for establishment.
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