Genome-Wide Association Mapping of Processing Quality Traits in Common Wheat (Triticum aestivum L.)

Abstract

Processing quality is an important economic wheat trait. The marker-assisted selection (MAS) method plays a vital role in accelerating genetic improvement of processing quality. In the present study, processing quality in a panel of 165 cultivars grown in four environments was evaluated by mixograph. An association mapping analysis using 90 K and 660 K single nucleotide polymorphism (SNP) arrays identified 24 loci in chromosomes 1A, 1B (4), 1D, 2A, 2B (2), 3A, 3B, 3D (2), 4A (3), 4B, 5D (2), 6A, 7B (2) and 7D (2), explaining 10.2-42.5% of the phenotypic variances. Totally, 15 loci were stably detected in two or more environments. Nine loci coincided with known genes or QTL, whereas the other fifteen were novel loci. Seven candidate genes encoded 3-ketoacyl-CoA synthase, lipoxygenase, pyridoxal phosphate-dependent decarboxylase, sucrose synthase 3 and a plant lipid transfer protein/Par allergen. SNPs significantly associated with processing quality and accessions with more favorable alleles can be used for marker-assisted selection.

Keywords: GWAS; SNP array; bread wheat; mixograph; wheat quality.

Figure 1

Manhattan plots for mixograph-related traits in 165 wheat accessions by the mixed linear model (MLM) in Tassel v5.0. MPT: mixograph midline peak time; MPV: mixograph midline peak value; MPW: mixograph midline peak width; MTxW: mixograph midline 8 min band width.13SX, 13AY, 14SX, 14AY and BLUP indicate Suixi 2013, Anyang 2013, Suixi 2014, Anyang 2014 and the best linear unbiased prediction (BLUP), respectively.