Thesis
Genetic and biochemical factors influencing essential oil composition in Melaleuca alternifolia (Cheel)
Southern Cross University, Centre for Plant Conservation Genetics
Doctor of Philosophy (PhD), Southern Cross University
2001
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Abstract
Melaleuca alternifolia (Cheel) is a commercially important, cultivated Australian native tree harvested for its monoterpene-rich essential oil. The key monoterpenes in tea tree oil are 1,8 cineole, terpinolene and terpinen-4-ol. The relative proportions of these three monoterpene constituents are used to differentiate the six naturally occurring chemotypes of this species. Only the chemotype high in terpinen-4-ol is grown commercially for the therapeutic and cosmetic industries as it is this oxygenated monoterpene to which the antiseptic properties are attributed.
Previous studies into the population structure of M. alternifolia by both isozyme and microsatellite analysis revealed little evidence for genetic structuring within genetic provenances. In contrast, analysis of the oil composition within these same regions showed distinct clustering of chemotypes within the provenances suggesting either that chemotype was a predominantly phenotypic affect, or that there is strong environmental selection for plant chemotypes. To investigate the level of genetic control of monoterpene composition in the essential oil of M. alternifolia, individuals representing the three extreme chemotypes of high terpinen-4-ol, high 1,8-cineole and high terpinolene were crossed with an individual with the commercially desirable, high terpinen-4-ol oil profile and grown under uniform conditions. The results clearly showed that chemotype was under strong genetic control although the actual details of inheritance remain unclear.
Details
- Title
- Genetic and biochemical factors influencing essential oil composition in Melaleuca alternifolia (Cheel)
- Creators
- Dale Andrew Shelton
- Contributors
- Robert J Henry (Supervisor) - Southern Cross UniversityPeter Baverstock (Supervisor) - Southern Cross UniversityDavid Leach (Supervisor) - Southern Cross University
- Awarding Institution
- Southern Cross University; Doctor of Philosophy (PhD)
- Theses
- Doctor of Philosophy (PhD), Southern Cross University
- Publisher
- Southern Cross University, Centre for Plant Conservation Genetics
- Number of pages
- viii, 146
- Identifiers
- 991012957299102368
- Copyright
- © Dale A. Shelton 2001
- Academic Unit
- Faculty of Science and Engineering; Southern Cross Plant Science
- Resource Type
- Thesis