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DNA fingerprinting in Rhododendrons using random amplified polymorphic DNA

University of British Columbia

The genus Rhododendron is one of the largest among the angiosperms, and has been the subject of intense interest in the horticultural field for the many species which are of commercial value. Hybrid rhododendrons are also valued, and many thousands of named cultivars have been registered with the International Rhododendron Registry. Rhododendrons make up an important sector of British Columbia's nursery industry, as they thrive in the mild climate of the Lower Mainland and Vancouver Island. The RAPD marker technique was applied in rhododendrons, first for DNA fingerprinting of commercial cultivars, and secondly, to study relationships within the genus For DNA fingerprinting, samples of rhododendron hybrids were obtained from Clay's Nursery in Langley, B.C. Reproducibility of the RAPD technique was established, as was clonal stability of the banding patterns generated. Thirteen RAPD primers were selected and used to generate RAPD banding patterns for the hybrid cultivars. Keys to identification of these cultivars were created based on the presence or absence of certain bands. The reproducibility of RAPDs coupled with the high level of polymorphism generated and the simplicity of the protocol makes the technique a good candidate for use in industry as a tool for quality control and identification of individuals whose identity may be in question. RAPDs were also evaluated for use in parentage analysis in rhododendrons. However, the relatively high frequency of non-parental bands observed limits the usefulness of the technique to certain situations in which there are only a few putative parents. For the taxonomic study, samples were collected from species in subsection Fortunea, as well as from some species thought to be related, and from an outgroup species. Cluster analysis on RAPD data generated from these samples did not give any evidence for the postulated relationships, but did highlight some other relationships. Individuals of the same species were generally clustered together, and individuals of the outgroup species were clustered in a distinct group from the other species. No distinctions were observed between species from more closely related subsections, however, which gives rise to questions regarding the current classification of Rhododendron. Further work is required to clarify and define these relationships.

Thesis/Dissertation

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2009-03-11

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http://hdl.handle.net/2429/5892

Genetics

University of British Columbia

UBCV

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