Labuschagne, M. T.Swart, W. J.Herselman, L.Mashope, Barbara Keitumetse2015-10-202015-10-202007-052007-052007-05http://hdl.handle.net/11660/1415English: South Africa hosts one of the largest cactus pear germplasm collections in the world. However, not all the varieties have been fully characterised, and evaluated for fruit quality, nutritional quality for use as fodder, and disease resistance. In this study, 38 South African cactus pear (Opuntia ssp.) varieties were characterised using AFLP markers to circumvent G X E effect on phenotypic characterisation. With the use of nine primer combinations, the varieties were grouped into four main clusters based on 346 fragments (per sample) of which 48% were polymorphic between samples. The dendrograms generated indicated that commercially cultivated varieties were dispersed amongst the different clusters indicating that they represent the genetic diversity within the germplasm. Genotype specific fragments were generated using six primer combinations, allowing the unique identification of nine varieties, three of which are commercially cultivated (Meyers, Roedtan, and Santa Rosa). Varieties that are recommended for commercial cultivation in the Mokopane district of the Limpopo Province, based on fruit quality and yield are Gymno Carpo, Malta, Algerian, Morado, Meyers, and Roedtan. These varieties meet the minimum requirements for cactus pear fruit production in South Africa. Nutritional quality evaluation of pruned cladodes from a commercial orchard in the Free State Province indicated that the varieties, Malta, Gymno Carpo, and American Giant ranked the highest in terms of CP content. Varieties that yielded the highest DM content were Messina, Nepgen, and Cross X. Varieties that ranked the highest for OM content were Cross X, Nepgen, and Sicilian Indian Fig. Gymno Carpo and Malta are amongst the varieties recommended for cultivation for fruit, as such they can be used as dual purpose crops for the production of both fodder and fruit. Evaluation for disease resistance indicated a quantitative mode of resistance across all varieties for all three fungal pathogens tested. The most resistant varieties surveyed in this study across all three fungal pathogens were Amersfoort, Meyers, and Algerian. Roly Poly, Direkteur, and Zastron were the more susceptible varieties. Of the three fungal pathogens tested, P. virens was the least affected by the antagonistic activity of the yeast isolates. Isolate 25 (Rhodotorula mucilaginosa) performed well against all three pathogens, whilst the remainder of the isolates displayed inhibition at varying degrees.Afrikaans: Suid-Afrika besit een van die grootste turksvy kiemplasma versamelings in die wêreld. Al die variëteite is egter nog nie ten volle vir vrugkwaliteit, voedingswaarde vir veevoer en siekteweerstand gekarakteriseer of geëvalueer nie. In hierdie studie is 38 Suid- Afrikaanse turksvy (Opuntia ssp.) variëteite suksesvol m.b.v. AFLP merkers gekarakteriseer om die effek van G X E op fenotipiese karakterisering uit te skakel. Met die gebruik van nege voorvoerder kombinasies is die variëteite op grond van 346 fragmente (per monster) waarvan 48% polimorfies was in vier groepe verdeel. Kommersiële variëteite was tussen die verskillende groepe versprei, wat aangedui het dat hulle die genetiese diversiteit binne die kiemplasma verteenwoordig. Genotipe spesifieke fragmente is met ses voorvoerder kombinasies gegenereer, wat die unieke identifikasie van nege variëteite moontlik gemaak het, insluitend drie kommersiële variëteite (Meyers, Roedtan en Santa Rosa). Variëteite wat gebaseer op vrugkwaliteit en opbrengs vir kommersiële produksie in die Mokopane distrik van die Limpopo Provinsie, aanbeveel word, is Gymno Carpo, Malta, Algerian, Morado, Meyers en Roedtan. Hierdie variëteite voldoen aan die minimum vereistes vir turksvy produksie in Suid Afrika. Voedingswaarde analise van die gesnoeide kladodes van ‘n kommersiële boord in die Vrystaat Provinsie het aangedui dat die variëteite Malta, Gymno Carpo en American Giant die beste t.o.v. ruproteïen inhoud gevaar het. Die variëteite met die hoogste droëmassa inhoud was Messina, Nepgen en Cross X. Die variëteite wat die beste vir organiese inhoud gevaar het was Cross X, Nepgen en Sicilian Indian Fig. Gymno Carpo en Malta was van die variëteite wat vir vrugproduksie aanbeveel word. As sulks kan hulle vir dubbeldoel produksie vir beide veevoer en vrugte gebruik word. Evaluasie vir siekteweerstand het ‘n kwantitatiewe model vir weerstand oor alle variëteite vir al drie fungus patogene aangedui. Die mees weerstandbiedende variëteite vir al drie patogene was Amersfoort, Meyers en Algerian. Roly Poly, Direkteur en Zastron was die mees vatbare variëteite. Van die drie fungus patogene wat getoets is, was P. virens die minste deur antagonistiese aksie van gis isolate beïnvloed. Isolaat 25 (Rhodotorula mucilaginosa) het goed teenoor al drie die patogene gereageer, terwyl die res van die isolate inhibisie van verskillende grade getoon het.enThesis (Ph.D. (Plant Sciences (Plant Breeding))--University of the Free State, 2007Prickly pears -- IdentificationPrickly pears -- Germplasm resourcesPrickly pears -- South AfricaDisease screeningFruit qualityFungal pathogensNutritional qualityInhibitionGenotypingOpuntia ficus-indicaCactus pearBiocontrolAFLPAntagonistic yeastsFodderThesisUniversity of the Free State