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dc.contributor.advisorSpies, J. J.
dc.contributor.advisorKleynhans, R.
dc.contributor.authorMinnaar, Adre
dc.date.accessioned2018-01-19T10:35:08Z
dc.date.available2018-01-19T10:35:08Z
dc.date.issued2004-01
dc.identifier.urihttp://hdl.handle.net/11660/7645
dc.description.abstractEnglish: The genus Lachenalia belongs to the family Hyacinthaceae and the order Asparagales. Lachenalia is commonly known as the ‘Cape Cowslip’ and this small bulbous geophyte is endemic to South Africa. The genus contains hundred and twenty species and is essentially a genus of the winter rainfall regions of southern Africa. In an attempt to produce new and better ornamentals, breeding-programmes were developed. The Roodeplaat Vegetable and Ornamental Plant Institute of the ARC (ARC-Roodeplaat) developed an economically viable breeding-programme in South Africa, for the genus Lachenalia. The exceptional morphological variation in the genus Lachenalia led to the initiation of this breeding-programme in which the genus was developed into an ideal pot plant and twenty-five cultivars have been registered since. Factors of importance in the breeding programme are flower size, genetic variation within the genus, as well as polyploidy. Different chromosome numbers as well as different basic chromosome numbers have been reported for more than fifty Lachenalia species. When Crosby (1986) reviewed the genus, chromosome studies [made by Moffett (1936) and Crosby (1986)] lead to the division of the genus into five provisional groups. Basic chromosome numbers were used as one of the criteria in the delimitation of these groups. These chromosome numbers can contribute enormously to the taxonomic classification of the Lachenalia species. Very little DNA sequencing has been done in the genus Lachenalia. During this study chromosome numbers (mitosis and meiosis) and DNA sequencing (trnL-F region) were used to evaluate the phylogenetic relationships of the species within the Lachenalia orchioides group. Clustal G was used to align the sequences and PAUP to determine the phylogenetic relationship. The somatic chromosome numbers of 2n = 12, 14, 24, 28, 42 were observed in the L. orchioides group. Different basic chromosome numbers (6 and 7) were observed within L. mutabilis, but within the rest of the group the basic chromosome number was 7. The basic chromosome number of x = 7 occurs most frequently throughout the L. orchioides group and thus seems to be the predominant basic chromosome number. DNA sequencing results supported x=7 as original basic chromosome number of the L. orchioides group. L. fistulosa has not been classified into a group yet. The strict consensus cladograms (Fig. 4.1-4.4) as well as the basic chromosome number of seven supports L. fistulosa as part of this group. These results support the monophyly of the L. orchioides group, which indicates close relationships. The phylogenetic analysis did not resolve the variation in chromosome numbers of L. mutabilis. Molecular cytogenetics (GISH and FISH) together with sequencing of more genes may help to resolve this relationship.en_ZA
dc.description.abstractAfrikaans: Die genus Lachenalia behoort tot die familie Hyacinthaceae en die orde Asparagales. Hierdie genus is alom bekend as die ‘Kaapse Sleutelblom’ en is ook endemies tot Suid-Afrika. Lachenalia bestaan uit meer as ‘n honderd spesies en dit is hoofsaaklik ‘n genus wat voorkom in die winterrëenval-gebiede van Suid-Afrika. In die soeke na nuwer en beter sier-plante, is teelprogram ontwikkel. Die Landbou navorsingsraad te Roodeplaat (LNR-Roodeplaat), Pretoria het ‘n teelprogram van groot ekonomiese waarde vir Lachenalia in Suid-Afrika ontwikkel. Die uitsonderlike morfologiese variasie van die genus het gelei tot die teelprogram waarin die genus tot die ideale potplant ontwikkel is. Vyf-en-twintig kultivars is al geregistreer sedert die begin van hierdie teelprogram. Faktore wat ‘n groot rol speel in hierdie teelprogram, is: blomgrootte, genetiese variasie in die genus asook poliploïdie. Versillende chromosoomgetalle sowel as basiese chromosoomgetalle vir meer as vyftig Lachenalia spesies is reeds bekend. Crosby (1986) het die genus in oorsig geneem en na verskeie chromosoom-studies (Moffett, 1936; Crosby, 1986) is die genus in vyf voorlopige groepe ingedeel. Basiese chromosoomgetalle was gebruik as een van die bepalende kenmerke in die indeling van hierdie groepe. Hierdie chromosoomgetalle kan grootliks bydrae tot die taksonomiese klassifikasie van die spesies in die genus. Baie min molekulêre werk, veral DNA volgordebepaling is van te vore op Lachenalia gedoen. Chromosoomgetalle (mitose en meiose) asook DNA volgordebepaling is in hierdie studie gebruik om die genomiese verhoudings van die spesies in die Lachenalia orchioides groep te evalueer. Die DNA volgordes is in lyn gestel deur Clustal G te gebruik en PAUP is gebruik om al die kladogramme op te stel. Somatiese chromosoomgetalle van 2n = 12, 14, 24, 28 en 42 is tydens hierdie studie in die L. orchioides groep waargeneem. Verskillende basiese chromosoomgetalle van x = 6 en 7 is vir L. mutabilis waargeneem, terwyl die res van die groep ‘n deurlopende basiese chromosoomgetal van sewe getoon het. Die basiese chromosoomgetal van sewe word as oorheersende basiese chromosoomgetal beskou, omdat dit deurlopend in die groep voorkom. Die DNA volgordebepaling resultate het sewe as basiese chromosoomgetal van die L. orchioides groep gesteun. L. fistulosa was nog nooit van te vore in enige van die groepe ingedeel nie, maar al die kladogramme (Fig. 4.1-4.4) asook die basiese chromosoomgetal van die spesie dui daarop dat dit tot die L. orchioides groep behoort. Al die resultate steun die monofilie van die groep, wat ‘n aanduiding is dat al die spesies in die groep naverwant aan mekaar is. Die filogenetiese analise het nie die voorkoms van die verskillende basiese chromosoomgetalle in L. mutabilis opgelos nie. Molekulêre sitogenetika (GISH en FISH) tesame met die DNA volgordebepalings van meer gene, mag dalk lig op die verwantskappe werp.af
dc.description.sponsorshipFoundation for Research Developmenten_ZA
dc.language.isoenen_ZA
dc.publisherUniversity of the Free Stateen_ZA
dc.subjectLachenalia orchioides groupen_ZA
dc.subjectCytogeneticsen_ZA
dc.subjectBasic chromosome numberen_ZA
dc.subjectDNA-sequencingen_ZA
dc.subjecttrnL-F regionen_ZA
dc.subjectGenomic relationshipsen_ZA
dc.subjectHyacinthaceae -- Breeding -- South Africaen_ZA
dc.subjectGenomicsen_ZA
dc.subjectCytogeneticsen_ZA
dc.subjectMolecular geneticsen_ZA
dc.subjectDissertation (M.Sc. (Plant Sciences: Genetics))--University of the Free State, 2004en_ZA
dc.titleGenomic relationships in the Lachenalia orchioides groupen_ZA
dc.typeDissertationen_ZA
dc.rights.holderUniversity of the Free Stateen_ZA


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