| Project/Area Number |
14560011
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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 | KYOTO UNIVERSITY |
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Principal Investigator |
SHIRAIWA Tatsuhiko Kyoto University, Graduate School of Agriculture, Associate Professor, 農学研究科, 助教授 (30154363)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAZAKI Tetsuya Kyoto University, Graduate School of Agriculture, Assistant Professor, 農学研究科, 助手 (60217693)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2004: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2003: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2002: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | cytokinin / delayed stem senescence / model / nitrogen / RIL / sink / soybean / temperature / ソース / 老化 |
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| Research Abstract |
The aim of this project is to identify environmental and genetic factors causing the symptom of "delayed stem senescence(DSS)" in soybean, which has recently increased in the soybean production area. The development of pod organs, fixation and partitioning of nitrogen during pod-fill and duration of pod filling stage were examined for the soybean crop/plants grown under various air-temperature and soil-water conditions. A QTL analysis also was conducted for the DSS trait.
1.The effect of temperature on development of reproductive organs and the occurrence of DSS : Six soybean cultivars were grown in the Temperature Gradient Chambers(TGC) and four temperature plots (T1-T4) with mean temperatures from 23.1 (T1) to 25.8(T4)℃) were established in the TGC during the period after the flowering stage. The number of perfect kernels per floret, single perfect kernel weight and seed yield were significantly lower in T4 than in T1. However, the effect of temperature on the occurrence of DSS was no
… More
t evident. On the other hand, the effect of cultivar on the DSS occurrence was evident irrespective to temperature conditions.
2.The effect of soil water condition on the nitrogen balance, cytokinin flux and occurrence of DSS : Three experiments with soil water treatments were conducted using cv. Tachinagaha. A moderate water deficit significantly reduced nitrogen fixation during pod-filling resulting in a relative shortage of nitrogen for seed filling and decreased the DSS symptom. Excess water during pod filling or temporal water deficit during 20 days after R5 caused reduced pod number and higher flux of trans-zeatin riboside in the xylem throughout pod filling stage. It was concluded that unfavorable soil water condition, especially its unstableness, would increase occurrence of DSS through lowered sink/source ratio for nitrogen and also increased supply of cytokinin from the root.
3.The genetic factors causing DSS : A QTL analysis on the DSS trait was conducted for two years using the recombinant inbred lines (RILs) from a cross between Peking and Tamahomare. One QTL was detected on the linkage-group L in both years and it was located close to Dtl, which is known as the major locus for the indeterminate/determinate trait. There were several QTLs detected but their involvement in DSS were inconsistent between years. Although the genetic factors of DSS seem to have great interactions with environmental conditions, there is a possibility that a major genetic factor exists near Dtl or as a pleiotropic effect of that locus. Less
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