Year: 2020
Type: dissertation
Abstract: Bread wheat (Triticum aestivum L.) is an important cereal crop that provides over 20% of \nthe global calorie intake. With the world population constantly growing, yield production \nmust increase to meet food demands. Wheat plays a significant role on nutritional and food \nsecurity especially in rural areas, however, bread wheat grains are known to be inherently \ndeficient in micronutrients, particularly Fe and Zn, which makes them important \nbiofortification targets. To date, South African wheat genotypes have not been explored for \ntheir nutritional micronutrient variation; hence there is a need to investigate the variation of \nnutritional quality and its association with yield components. Bread wheat cultivars, TugelaDN and Elands were used in this study based on their known high yield potential, resistance \nto insect pests and diseases as well as their good-to-excellent bread-making quality. The \ngoal of this study was to use a doubled haploid (DH) mapping population, developed from \na cross between cultivars Tugela-DN and Elands, to identify single nucleotide \npolymorphism (SNP) and genotyping-by-sequencing (GBS)-based markers linked to high \nnutritional quality and yield-related traits. This was achieved by (i) determining grain \nmicronutrient (Fe and Zn) concentration variation in 139 lines of a DH mapping population; \n(ii) evaluating the mapping population for yield-related traits; (iii) determining the correlation \nbetween micronutrient and yield-related traits among the genotypes; (iv) identifying SNP \nGBS-based markers linked to the high minerals and yield-related traits. The analysis of \nvariance (ANOVA) showed significant (P<0.001) differences between genotypes for all \ntraits evaluated. A wide variation was observed for both GFeC and GZnC. The statistical \nanalysis revealed significant variation for Zn concentration (P < 0.001) among genotypes \nand not significant Fe concentration. DArT-Seq was used to genotype Tugela-DN and \nElands cultivars and 139 DH genotypes. Quantitative trait loci (QTL) were detected using \nSNP GBS-based markers on chromosome 2D, 5B, 5D, 6A, and 6B for GZnC, and on \nchromosome 2D, 5B, 5D and 7D for GFeC. Most QTLs identified for GFeC and GZnC \nshared the genomic interval and some of them also co-located with few yield-related traits. \nThe results of this study will contribute to breeding programmes to improve nutritional \nquality of bread wheat and food security of the country.
Author: Mantshiuwa Christinah Lephuthing
Language: English
Subfield: Plant Science
Domain: Life Sciences
Open Access status: green
Funder: National Research Foundation
OpenAlex ID: W3122026602