Department of Crop and Soil Sciences, Washington State University, Pullman, WA, 99164, USA.
USDA-ARS Plant Science Research Campus, Raleigh, NC, 27695, USA.
Theor Appl Genet. 2021 Aug;134(8):2547-2559. doi: 10.1007/s00122-021-03841-y. Epub 2021 May 30.
The novel super-soft kernel phenotype has the potential to improve wheat processing and flour quality. We identified genomic regions associated with this kernel texture in white winter wheat. Grain hardness is a key determinant of wheat milling and baking quality. The recently discovered 'super-soft' kernel phenotype has the potential to improve wheat processing and flour quality. However, the genetic basis underlying the super-soft trait in wheat is not yet well understood. In this study, we investigated the phenotypic and genotypic structure of the super-soft trait in a collection of 172 advanced soft white winter wheat breeding lines and cultivars adapted to the Pacific Northwest region of the USA. This collection had a continuous distribution for grain hardness index (single-kernel characterization system). Ten super-soft genotypes showed hardness index ≤ 12 including the cultivar Jasper. Over 98,000 SNP markers from genotyping-by-sequencing were used for association mapping (GWAS). The GWAS identified 20 significant markers associated with grain hardness. These significant SNPs corresponded to seven QTL on chromosomes 2B, 3A, 3B, 5A, 6B,7A, and one unaligned chromosome. Two of these QTL, QSKhard.wql-3A and QSKhard.wql-5A, had large effects and distinguished between the normal soft and the super-soft classes. QSKhard.wql-3A and QSKhard.wql-5A reduced the hardness index by 11.7 and 13.1 on average, respectively. The remaining QTL had small effects and reduced grain hardness within the normal soft range. QSKhard.wql-2B, QSKhard.wql-3A, QSKhard.wql-3B, and QSKhard.wql-6B were not previously reported to be in genomic regions of grain hardness-related genes/QTL. The identified super-soft genotypes as well as the SNPs associated with lower grain hardness will be useful to assist breeding for this grain texture trait.
新型超软粒型有望改善小麦加工和面粉品质。我们在白冬小麦中鉴定与这种粒型质地相关的基因组区域。籽粒硬度是决定小麦制粉和烘焙品质的关键因素。最近发现的“超软”粒型有望改善小麦加工和面粉品质。然而，小麦超软特性的遗传基础尚不清楚。在这项研究中，我们研究了 172 个适应美国太平洋西北地区的软白冬小麦育成系和品种的超软特性的表型和基因型结构。该群体的粒硬度指数（单粒特征系统）呈连续分布。包括 Jasper 在内的 10 个超软基因型的硬度指数≤12。利用来自测序的基因型-表型关联分析（GWAS）共获得 98,000 多个 SNP 标记。GWAS 鉴定出与粒硬度相关的 20 个显著标记。这些显著的 SNP 对应于染色体 2B、3A、3B、5A、6B、7A 上的 7 个 QTL 和一个未对齐的染色体。其中两个 QTL，QSKhard.wql-3A 和 QSKhard.wql-5A，具有较大的效应，可区分正常软质和超软质品种。QSKhard.wql-3A 和 QSKhard.wql-5A 可使硬度指数分别平均降低 11.7 和 13.1。其余的 QTL 具有较小的效应，在正常软质范围内降低籽粒硬度。QSKhard.wql-2B、QSKhard.wql-3A、QSKhard.wql-3B 和 QSKhard.wql-6B 以前未被报道为与籽粒硬度相关基因/QTL 的基因组区域。鉴定出的超软基因型以及与较低籽粒硬度相关的 SNP 将有助于辅助该粒型特性的选育。
