Tolerance to metribuzin, a broad-spectrum herbicide, is an important trait for weed control in wheat breeding. However, the genetics of metribuzin tolerance in relation to the underlying quantitative trait loci (QTL) and genes is limited. This study developed F₈ recombinant inbred lines (RILs) from a cross between a highly resistant genotype (Chuan Mai 25) and highly susceptible genotype (Ritchie), which were used for QTL mapping of metribuzin tolerance. Genotyping was done using a diversity arrays technology sequencing (DArTseq) platform, and phenotyping was done in controlled environments. Herbicide tolerance was measured using three traits, visual score (VS), reduction of chlorophyll content (RCC), and mean value of chlorophyll content for metribuzin-treated plants (MCC). A high-density genetic linkage map was constructed using 2,129 DArTseq markers. Inclusive composite interval mapping (ICIM) identified seven QTL, one each on chromosomes 2A, 2D, 3A, 3B, 4A, 5A, and 6A. Three major QTL—Qrcc.uwa.2AS, Qrcc.uwa.5AL, and Qrcc.uwa.6AL—explained 11.39%, 11.06%, and 11.45% of the phenotypic variation, respectively. The 5A QTL was further validated using kompetitive allele-specific PCR (KASP) assays in an F₃ validation population developed from Chuan Mai 25 × Dagger. Blasting the single-nucleotide polymorphisms (SNPs) flanking the QTL in the wheat reference genome RefV1.0 revealed SNP markers within or very close to annotated genes which could be candidate genes responsible for metribuzin tolerance. Most of the candidate genes were related to metabolic detoxification, especially those of P450 pathway and xenobiotic transmembrane transporter activity, which are reportedly key molecules responsible for herbicide tolerance. This study is the first to use specially developed populations to conduct QTL mapping on the metribuzin tolerance trait. The three major QTL and candidate genes identified in this study could facilitate marker-assisted metribuzin breeding in wheat. The QTL could be fine-mapped to locate the genes responsible for metribuzin tolerance, which could be introgressed into elite wheat cultivars.

耐受性广谱除草剂metribuzin是小麦育种中杂草控制的重要特征。但是，与基础的数量性状基因座（QTL）和基因相关的美法津耐受性的遗传学是有限的。这项研究开发了F ₈来自高抗性基因型（传麦25）和高度易感基因型（Ritchie）之间杂交的重组自交系（RIL），用于Metribuzin耐性的QTL作图。基因分型是使用多样性阵列技术测序（DArTseq）平台完成的，而表型是在受控环境中完成的。除草剂耐受性是通过三个特征进行测量的：视觉评分（VS），叶绿素含量的降低（RCC）和用三甲嗪处理过的植物（MCC）的叶绿素含量的平均值。使用2,129个DArTseq标记构建了高密度遗传连锁图。包含性复合间隔图谱（ICIM）鉴定了七个QTL，每个在2A，2D，3A，3B，4A，5A和6A染色体上。三个主要的QTLQrcc.uwa.2AS， Qrcc.uwa.5AL和 Qrcc.uwa.6AL —分别解释了表型变异的11.39％，11.06％和11.45％。在F _3中使用竞争性等位基因特异性PCR（KASP）分析进一步验证了5A QTL验证人群来自Chuan Mai 25×Dagger。小麦参考基因组RefV1.0中位于QTL侧翼的单核苷酸多态性（SNP）的爆破揭示了SNP标记位于注释基因内或非常接近注释基因，这些基因可能是引起Metribuzin耐受的候选基因。大多数候选基因与代谢解毒有关，尤其是P450途径和异源跨膜转运蛋白的活性，据报道这是造成除草剂耐受性的关键分子。这项研究是第一个使用专门开发的种群对甲氧苄青霉素耐受性特征进行QTL定位的研究。在这项研究中确定的三个主要的QTL和候选基因可以促进小麦的标记辅助metribuzin育种。可以对QTL进行精细定位，以找到负责甲氧苄西林耐受性的基因，