| dc.description.abstract | Durum wheat (Triticum turgidum L. ssp. durum Desf.) is one of the main crops for human consumption, and it is an essential ingredient for pasta production. The color of pasta can range from bright yellow to dim brown. Pasta brightness and yellowness are important quality indicators for producers and customers. Releasing durum wheat cultivars capable of producing pasta products with high yellow color can be an important goal for breeders. Yellow pigment content (YPC) is one of the important components that affect pasta color. The yellow color of pasta is not necessarily dictated by the presence of YPC; soluble brown pigment (SBP) and enzymes such as polyphenol oxidase (PPO) and peroxide (POD) are other factors that contribute to pasta color. Marker-assisted selection (MAS) can accelerate the selection process for breeding programs that develop new durum wheat cultivars with high yellow color. This dissertation used quantitative trait loci (QTL) mapping to identify QTL for these color-related traits. Two populations, each with 192 recombinant inbred lines (RILs), were developed from crosses between Joppa and D12118 (Population one [POP1]) and Mountrail and Carpio (Population two [POP2]). The phenotyping of these traits was carried out in two locations in North Dakota, USA. Genotyping of the RIL populations was conducted using the wheat Illumina iSelect 90K SNP assay. There were significant phenotypic differences among the genotypes for all traits. In POP1, entry lines 32 and 78 with both high YPC and low SBP, and in POP 2 entry lines 1, 82, and 101 with high YPC could be excellent sources for improving the yellow color in durum wheat. In this study, 31 Additive QTL (A-QTL) and 370 minor digenic epistatic QTL (DE-QTL) associated with all four traits were identified. In Pop1, the most significant A-QTL were detected on Chromosomes 5A (D1.SBP5A.ndsu) for SBP and 5B (D1.YPC5B.ndsu) and 6B (D1.YPC6B.ndsu) for YPC. In POP2, major A-QTL were found on chromosomes 7A (D2.YPC7A.ndsu), 2A (D2.PPO2A.ndsu), and 3A (D2.POD3A.ndsu) for YPC, PPO, and POD, respectively. The information provided in the current study could be employed with MAS to increase selection efficiency and improve the color of durum wheat. | en_US |
