Durum wheat (Triticum turgidum L. ssp. durum) is an important food crop worldwide. Modern breeding has yielded elite durum wheat cultivars with improved grain yield, end‐use quality, and disease resistance. In this study, we compared 150 breeding lines from the North Dakota State University (NDSU) durum wheat breeding program to 163 durum landraces using a large set of single nucleotide polymorphism (SNP) markers. We found that the genetic diversity of the NDSU durum breeding population was decreased by ∼60% relative to collection of 163 landraces. Selective sweep analysis identified several candidate regions that might have undergone breeding selection. Also in this study, over 260 worldwide durum wheat accessions were evaluated in drought environments of the northern Great Plains for 3 yr, a major growing area of durum wheat in the United States. One line showed significantly higher grain yield than the local elite cultivars. A number of lines showed significantly higher grain yield component traits like seeds per spike and thousand‐kernel weight. Those desirable lines may contain complementary favorable alleles and can possibly be used to improve grain yield under drought stress. Genome‐wide association mapping found no major quantitative trait loci (QTL) but a number of QTL with minor effect for grain yield, which could be explained by grain yield's complex genetic nature, the rare frequency of the novel complementary alleles, and the limited number of environments and replications for phenotypic evaluation in the study. Further QTL mapping using biparental populations derived from the identified desirable lines and elite cultivars may be able to identify the QTL related to grain yield, which can facilitate introgression of the complementary favorable alleles through marker‐assisted selection.

中文翻译：

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大平原北部干旱环境下硬质小麦种质遗传多样性和农艺性状评估

硬粒小麦（圆锥小麦L. SSP 。杜伦麦）是全球重要的粮食作物。现代育种产生了硬粒硬质小麦品种，具有提高的单产，最终使用质量和抗病性。在这项研究中，我们使用大量的单核苷酸多态性（SNP）标记将北达科他州立大学（NDSU）硬质小麦育种计划的150个育种系与163个硬质小麦地方品种进行了比较。我们发现，相对于163个地方品种，NDSU硬粒小麦育种种群的遗传多样性降低了约60％。选择性扫描分析确定了可能已经进行育种选择的几个候选区域。同样在这项研究中，在大平原北部北部干旱环境下进行了为期3年的评估，评估了全世界260种硬质小麦的收成，这是美国硬质小麦的主要产区。一条品系显示出比当地优良品种高得多的谷物产量。许多品系显示出较高的籽粒产量构成特征，例如每穗种子和千粒重。这些理想的品系可以包含互补的有利等位基因，并且可以用于提高干旱胁迫下的谷物产量。全基因组关联图谱没有发现主要的数量性状基因座（QTL），但是有一些对籽粒产量影响较小的QTL，这可以用籽粒产量的复杂遗传特性，新型互补等位基因的稀有频率以及数量有限来解释。表型评估的环境和复制的研究。