2018 Fiscal Year Final Research Report
Comparion of expression levels of CCD4 gene among azalea species belonging to subgenus tsutsusi and its application to breeding of yellow flowered evergreen azaleas
| Project/Area Number |
16K07602
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Horticultural science
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| Research Institution | University of the Ryukyus |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
宮島 郁夫 九州大学, 熱帯農学研究センター, 准教授 (20182024)
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Keywords | ツツジ / カロテノイド / CCD4 |
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| Outline of Final Research Achievements |
Intersubgeneric crosses between white-flowered evergreen azalea species and Rhododendron japonicum f. flavum can produce yellow-flowered evergreen azaleas. The petal color of F1 progenies is known to fade during petal development, due to a high expression of the CCD4 gene inherited from the evergreen species. In this study, to facilitate the selection of evergreen azalea species as cross parents that have low expression levels of CCD4 in developing petals, CCD4 expression levels were compared among 16 evergreen azalea species. The expression levels of CCD4 genes in petals of evergreen azalea species at the day of anthesis varied widely from 2 to 20 times relative to that in R. japonicum. Among these species, R. amanoi maintained low CCD4 expression levels throughout all petal development stages, which were not significantly different from those of R. japonicum. This species, therefore, is considered a promising breeding material for producing yellow-flowered evergreen azaleas.
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| Free Research Field |
園芸科学
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| Academic Significance and Societal Importance of the Research Achievements |
花卉類における黄花品種の作出は，多くの種目において育種目標としてあげられている．常緑性黄色花ツツジ作出を目的とした，白花常緑性ツツジと黄花落葉性キレンゲツツジとの交配において，F1実生は，カロテノイド色素生合成能自体は優性形質としてキレンゲツツジから遺伝しているものの，常緑性種より遺伝したCCD4の高発現により退色化している．本研究では，複数の常緑性ツツジ種について開花花弁におけるCCD4遺伝子発現量を調査し，発現量の低い常緑性種を明らかにしている．この結果は，今後，本種を交配親に用いることで，常緑性黄色花ツツジ作出の可能性を示しており，学術的意義がある．
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