Wheat pre-breeding towards disease resistance of fungal pathogens

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dc.contributor.advisorBotes, Willem C.en_ZA
dc.contributor.advisorRose, Lindy J.en_ZA
dc.contributor.authorWhite, Michaela-Anneen_ZA
dc.contributor.otherStellenbosch University. Faculty of Agrisciences. Dept. of Genetics.en_ZA
dc.date.accessioned2023-03-03T16:17:10Z
dc.date.accessioned2023-05-18T07:06:06Z
dc.date.available2023-03-03T16:17:10Z
dc.date.available2023-05-18T07:06:06Z
dc.date.issued2023-03
dc.descriptionThesis (MScAgric)--Stellenbosch University, 2023. en_ZA
dc.description.abstractENGLISH ABSTRACT: Bread wheat is an important grain crop cultivated globally, serving as the main source of calories and protein to approximately 4 billion individuals. To sustain increasing consumer demands, the production of wheat is required to increase with 60% by 2050. Wheat production is often threatened by the occurrence of both abiotic and biotic stressors, resulting in reduced yields. The most economically important biotic stressors constraining the production of wheat are fungal diseases. Management strategies have been developed to control disease outbreaks. The integration of disease resistance is highly favoured as it is cost-effective, environmentally friendly and reduces the risk of disease outbreaks. The aim of the study was to identify crossing parents to introduce into the male-sterility mediated marker-assisted recurrent selection pre-breeding programme. The SU-PBL’s 2020 wheat nursery and Fusarium head blight CIMMYT nursery used as male crossing parents, were genotypically and phenotypically assessed for powdery mildew resistance (Pm37, Pm4b, MLAG12, MLUM15) and Fusarium head blight resistance (Qfhs.ifa.5A, 7AQTL, Qfhs.ndsu.3BS), respectively. Two superior genotypes with FHB resistance were identified from the FHB CIMMYT nursery. The two wheat lines displayed low disease severity, low DON content and minimal FDK. Five superior wheat lines with powdery mildew resistance were identified from the SU-PBL’s 2020 wheat nursery. These superior wheat lines displayed promising genotypic and phenotypic expressions for introduction into the MS-MARS pre-breeding scheme. Future studies should include additional molecular and phenotypic characterisation of the nurseries. It should also include active powdery mildew resistance breeding. Due to the expected change in climatic conditions worldwide, an increased risk of powdery mildew outbreaks is expected for South Africa. Extensive breeding for powdery mildew disease resistance through the deployment of several viable genes would reduce this threat.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Koring is ’n baie belangrike graangewas wat wêreldwyd gekweek word, en dien as die primêre bron van kalorieë en proteïene vir ongeveer 4 miljard individue. Om aan die toenemende aantal verbruikers se aanvraag te voldoen word daar vereis dat koringproduksie toeneem met ongeveer 60% teen die jaar 2050. Die produksie van koring word dikwels bedreig deur die teenwoordigheid van beide biotiese en abiotiese stressors wat gevolglik lei tot verlaagde opbrengs. Die mees belangrike ekonomiese biotiese stressors wat koringproduksie beperk, is swamsiektes. Beheerstrategieë moet in plek gestel word om die uitbraak van siektes te beperk. Die integrasie van weerstand teen siektes is dus belangrik omdat dit koste-effektief en omgewingsvriendelik is, asook die risiko van die uitbraak van siektes verminder. Die doelwit van hierdie studie was om kruisings-ouers te identifiseer en tot die manlik steriliteit merkerbemiddelde herhalende seleksie (MS-MBHS) voortelings program toe te voeg. Die Universiteit van Stellenbosch se planteteeltlaboratorium (US-PL) se 2020 koring en CIMMYT se aarskroeisiekte kwekerye, is as manlike kruisings-ouers gebruik en is genotipies en fenotipies apart vir witroesweerstand (Pm37, Pm4b, MLAG12, MLUM15) en aarskroeiweerstand (Qfhs.ifa.5A, 7AQTL, Qfhs.ndsu.3BS) getoets. Twee hoofgenotipes met aarskroeiweerstand is geïdentifiseer uit die CIMMYT aarskroeisiekteweerstand kwekery. Die twee koringlyne het lae infeksievlakke, lae DON-inhoud en minimale FDK getoon. Vyf hoofkoringlyne met witroesweerstand is geïndentifiseer uit die US- PL se 2020 kwekery. Dié koringlyne het belowende genotipiese en fenotipiese uitdrukking getoon vir toevoeging tot die MS-MBHS voortelingskema. Toekomstige navorsing moet daarop fokus om addisionele molekulêre en fenotipiese karakterisering van die kwekery in te sluit, asook aktiewe witroesweerstandsteling. As gevolg van die verwagde wêreldwye verandering in klimaatstoestande, word ’n verhoogde risiko vir witroesuitbraak vir Suid-Afrika voorspel. Uitgebreide witroessiekteweerstandsteling deur die vrystelling van weerstandsgene, sal hierdie bedreiging verminder.af_ZA
dc.description.versionMastersen_ZA
dc.format.extentxiv, 120 pages : illustrations (some color), mapsen_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/127137
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subject.lcshWheat -- Breeding -- South Africaen_ZA
dc.subject.lcshWheat -- Disease and pest resistance -- Genetic aspectsen_ZA
dc.subject.lcshWheat rusts -- Environmental aspects -- South Africaen_ZA
dc.subject.lcshWheat fusarium culmorum head blight -- Genetic aspectsen_ZA
dc.subject.lcshFusarium -- Pathogenesisen_ZA
dc.subject.lcshPowdery mildew diseases -- Effect of temperature onen_ZA
dc.subject.lcshWheat -- Diseases and pests -- Climatic factorsen_ZA
dc.subject.nameUCTDen_ZA
dc.titleWheat pre-breeding towards disease resistance of fungal pathogensen_ZA
dc.typeThesisen_ZA
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