Cytogenetic and molecular studies of Dahlia Cav. species and hybrids.

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dc.contributor.advisor Murray, Brian en Gatt, Melanie Kaye en 2007-07-11T02:23:25Z en 2007-07-11T02:23:25Z en 1998 en
dc.identifier THESIS 98-439 en
dc.identifier.citation Thesis (PhD--Biological Sciences)--University of Auckland, 1998 en
dc.identifier.uri en
dc.description Full text is available to authenticated members of The University of Auckland only. en
dc.description.abstract The genus Dahlia Cav. (Asteraceae, Heliantheae-Coreopsidinae) contains a range of chromosome numbers, with x=16, 17 and 18. Observations on the chromosomes of species of Dahlia based on x=16 showed that some have 2n=32, others 2n=64,with a third group having both chromosome numbers in the same taxon. Karyotype investigations showed that the chromosomes can be divided into groups of 14 metacentrics plus two different sized submetacentrics per set of l6 chromosomes. Meiotic analysis at metaphase I and pachytene,by synaptonemal complex spreading, showed that the 2n=32 species have exclusive bivalent formation whereas the 2n=64 species have small numbers of univalents plus quadrivalents but that the majority of configurations are bivalents. This study proposes that Dahlia species with 2n=32 are allotetraploids whereas those species and chromosome races with 2n=64 are their autoploid derivatives. The presence of a bivalent-promoting mechanism in the 2n=32 species may account for their meiotic behaviour, as their component genomes appear so similar, and it is suggested that this mechanism is also responsible for the low number of quadrivalents in the 2n=64 taxa. en
dc.language.iso en en
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof PhD Thesis - University of Auckland en
dc.relation.isreferencedby UoA9985514714002091 en
dc.rights Restricted Item. Available to authenticated members of The University of Auckland. en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. en
dc.rights.uri en
dc.title Cytogenetic and molecular studies of Dahlia Cav. species and hybrids. en
dc.type Thesis en Biological Sciences en The University of Auckland en Doctoral en PhD en
dc.rights.holder Copyright: The author en
dc.identifier.wikidata Q112851559

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