Browsing by Author "Rhoda, Rayganah"
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- ItemImproving wheat grain yield by employing an integrated biotechnology approach(Stellenbosch : Stellenbosch University, 2018-03) Rhoda, Rayganah; Botes, Willem; Stellenbosch University. Faculty of AgriSciences. Dept. of Genetics.ENGLISH ABSTRACT: Wheat is a widely cultivated crop as it forms a significant part of the world’s diet, especially within developing countries. However, food insecurity is increasing at a rapid rate and to meet this demand, wheat yields need to increase by 50%, by the year 2050. To gain higher wheat yields, breeding efficiency needs to increase which can be done through employing biotechnological approaches that can aid in achieving increased yields. Yield, however, is quantitatively inherited and strongly influenced by the genotype x environment interaction. Therefore, yield-determining traits that have less genotype x environment interaction should be investigated to identify underlying inheritance of high yield, along with good husbandry practises that can result in increased wheat yield. The aim of this study was to assess high-yielding genotypes through validating yielddetermining traits using genotypic and phenotypic screening as well as the use of these highyielding genotypes as male crossing parents within the male-sterility marker-assisted mediated recurrent selection breeding (MS-MARS) scheme for the improvement of grain yield. The yield-determining traits as well as molecular markers associated to some of the yielddetermining traits were identified through literature. The molecular markers were validated through genotypic screening and each yield-determining trait was phenotypically screened for each genotype and statistically analysed. The validation of two mobile applications, SeedCounter and 1KK, that measures grain morphology was also executed. All molecular markers were validated as reliable diagnostic markers to be used in markerassisted selection (MAS) for identifying its specific yield-determining trait, except for one marker. The statistical analysis for the yield-determining traits displayed that three genotypes were better performing among this set of genotypes and therefore can be used as the male crossing parents within the next MS-MARS cycle. The association of the molecular marker with the yield-determining traits displayed negative correlations that suggests that the function of the high-yielding genes are different within this set of genotypes. Only the SeedCounter application was validated to be used as a future phenotyping tool for grain morphology and the MS-MARS cycles were successfully executed. Future studies should include the validation of more mobile applications, the identification of the relationship between yield and these molecular markers identified and QTL mapping to contribute to the understanding of the underlying genetic control of the desired phenotypes that contribute to higher grain yield.