Genetic analysis of end‐use quality traits in wheat

Abstract

Wheat (Triticum aestivum L.) is a major cereal food crop in the world. End‐use quality improvement is a major objective in wheat breeding programs. ‘Tiger’ is a hard white winter wheat cultivar with excellent bread baking qualities. The objective of this study was to identify the genetic loci underlying the quality traits in Tiger. A doubled‐haploid (DH) population derived from a cross between Tiger and ‘Danby’ was grown in two environments. A total of 17 quality traits together with grain yield (GY) and stripe rust (Puccinia striiformis f. sp. Tritici) were evaluated. The population was genotyped using single nucleotide polymorphism (SNP) markers generated through genotyping‐by‐sequencing (GBS). A linkage map was constructed with 1,507 GBS‐SNP markers that distributed over all 21 chromosomes. Most traits in this study showed normal or approximately normal distributions. Composite interval mapping analysis revealed a total of 72 quantitative trait loci (QTL), 67 for quality traits that were dispersed on all chromosomes except 3D, 5D, 6A, and 7A. Among the 67 QTL, some were novel QTL that have not been reported previously. Although many QTL were only significant in one environment, six genomic regions on chromosomes 1B, 1D, 2D, 5BL, 6B, and 6DL harbored major QTL for several important quality traits including kernel hardness (KH), grain and flour protein content (GPC, FPC), flour yield (FY), mix time (MT), mixing tolerance (MTOL), loaf volume (LV), and loaf volume regression (LVReg). At these major loci, Danby contributed favorable alleles for KH, GPC and FPC, while Tiger contributed favorable alleles for the other traits. The findings in this study will be useful for the genetic improvement of bread‐making quality in wheat.

Genetic Architecture of End-use Quality Traits in Soft White Winter Wheat

“…For instance, S2B_154846350, associated with SKCS size in this study, was located at 4-5 Mb from IWB30179 [2] and QKd.cob-1A (~ 134 Mb, [14]) that were associated with SKCS size and kernel diameter, respectively. Similarly, S2D_563799166 and S5A_578074731 were close to previously identi ed kernel diameter QTL, QKd.hwwgr-2DL (~ 552 Mb, [10]) and QKD.ksu-5A1 (568 Mb, [21]), respectively. For SKCS weight, S2D_563799166 identi ed in this study was positioned at ~12 Mb from QSkw.hwwgr-2DL (552 Mb, [10]) (Supplementary Table S6).…”

“…For instance, SKCS hardness associated markers in this study, S1A_583894689, S3A_690786387, S3B_718850970, S5A_480515221, S6B_130163859, S6B_705613777, and S7A_12011069 were located close to the positions of previously reported grain hardness associated markers/QTL, QGh.caas-1A (~575 Mb, [9]), wPt-4725 (709 Mb, [12]), QKh.WJ-3B.3 (~695 Mb, [8]), S5A_463766631 (464 Mb, [22]), IWB11485 (121 Mb, [2]), S6B_703822990 (704 Mb, [22]), wPt-0744 (0.2 Mb, [12]), respectively. Similarly, S1B_635869100 was positioned 8-13 Mb from Qgh-1B [13], QKh.WY-1B.1b [8], QGh.cass-1B [7], QNhi.hwwgr-1BL [10], and QKH.ksw-1B [21]. On chromosome 5B, S5B_549556474 identi ed in this study was found close to Qshi.hwwgr-5BL (566-571 Mb, [10]) and a QTL anked by the SSR marker wmc289 (556 Mb, [11]).…”

“…These GWAS MTAs from previous studies were associated with thousand kernel weight, test weight, grain ll duration, grain protein content, SDS sedimentation, and grain minerals (Cu and Zn) (Supplementary Table S5). Furthermore, comparative mapping (based on physical positions of molecular markers) between all the 178 identi ed MTAs from this study and end-use quality QTL/genes from previous genetic studies [2,4,[6][7][8][9][10][11][12][13][14][15][16][17][19][20][21][22] showed that 40 MTAs were positioned within genomic regions of previously discovered end-use quality genes/QTL (Supplementary Table S6).…”

“…In addition, we extracted MTAs available at the International Wheat Genome Sequencing Consortium (IWGSC) sequence repository that were within the genomic regions of large effect MTAs. Furthermore, markers (SNP, simple sequence repeat: SSR, Diversity Arrays Technology: DArT) associated with end-use quality in previous genetic studies [2,4,[6][7][8][9][10][11][12][13][14][15][16][17][19][20][21][22] and physically close (based on T. aestivum RefSeq v1.0 reference genome) to all MTAs in this study were determined.…”

“…Since most end-use quality traits are predominantly controlled by genetic factors [3,4,5], a better understanding of the underlying genetic architecture of the various traits can support strategies for both phenotypic and genotypic selection, including an assessment of the potential effectiveness of marker-assisted selection. Analysis of marker trait associations have identi ed numerous quantitative trait loci (QTL) for different end-use quality traits distributed across all 21 wheat chromosomes [2,4,[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. However, most of these studies were performed in hard wheat (bread wheat) with limited investigations [2,4,17,22,23] being performed in soft wheat.…”