Masters Degrees (Genetics)

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Browsing Masters Degrees (Genetics) by browse.metadata.advisor "Botes, Willem C."

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    Wheat pre-breeding towards disease resistance of fungal pathogens
    (Stellenbosch : Stellenbosch University, 2023-03) White, Michaela-Anne; Botes, Willem C.; Rose, Lindy J.; Stellenbosch University. Faculty of Agrisciences. Dept. of Genetics.
    ENGLISH 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.