Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota 55108.
Department of Crop and Soil Sciences, North Carolina State University, Raleigh, North Carolina 27695.
Genetics. 2019 Oct;213(2):595-613. doi: 10.1534/genetics.119.302046. Epub 2019 Jul 29.
Germplasm collections hold valuable allelic diversity for crop improvement and genetic mapping of complex traits. To gain access to the genetic diversity within the USDA National Small Grain Collection (NSGC), we developed the Barley Recombinant Inbred Diverse Germplasm Population (BRIDG6), a six-row spring barley multiparent population (MPP) with 88 cultivated accessions crossed to a common parent (Rasmusson). The parents were randomly selected from a core subset of the NSGC that represents the genetic diversity of landrace and breeding accessions. In total, we generated 6160 F recombinant inbred lines (RILs), with an average of 69 and a range of 37-168 RILs per family, that were genotyped with 7773 SNPs, with an average of 3889 SNPs segregating per family. We detected 23 quantitative trait loci (QTL) associated with flowering time with five QTL found coincident with previously described flowering time genes. A major QTL was detected near the flowering time gene, which affects photoperiod. Haplotype-based analysis of identified private alleles to families of Asian origin conferring both positive and negative effects, providing the first observation of flowering time-related alleles private to Asian accessions. We evaluated several subsampling strategies to determine the effect of sample size on the power of QTL detection, and found that, for flowering time in barley, a sample size >50 families or 3000 individuals results in the highest power for QTL detection. This MPP will be useful for uncovering large and small effect QTL for traits of interest, and identifying and utilizing valuable alleles from the NSGC for barley improvement.
种质资源收集为作物改良和复杂性状的遗传图谱提供了有价值的等位基因多样性。为了利用美国农业部国家小谷物收集（NSGC）中的遗传多样性，我们开发了大麦重组自交系多样化种质资源群体（BRIDG6），这是一个六棱春大麦多亲本群体（MPP），由 88 个栽培品种与一个共同亲本（Rasmusson）杂交而成。亲本是从 NSGC 的核心亚群中随机选择的，这些亚群代表了地方品种和育种种质的遗传多样性。总共生成了 6160 个 F6 重组自交系（RIL），每个家系的平均 RIL 数为 69，范围为 37-168，这些 RIL 用 7773 个 SNP 进行了基因型分析，每个家系的平均 SNP 数为 3889 个。我们检测到与开花时间相关的 23 个数量性状位点（QTL），其中 5 个 QTL 与先前描述的开花时间基因一致。在一个影响光周期的开花时间基因附近检测到一个主要的 QTL。基于单倍型的分析确定了与亚洲起源的家系相关的特有等位基因，这些等位基因具有正向和负向效应，首次观察到与亚洲品种相关的开花时间相关等位基因的特有性。我们评估了几种抽样策略，以确定样本大小对 QTL 检测能力的影响，发现对于大麦的开花时间，样本大小>50 个家系或 3000 个个体可使 QTL 检测的能力达到最高。该 MPP 将有助于发现感兴趣性状的大、小效应 QTL，并鉴定和利用 NSGC 中的有价值等位基因来改良大麦。
