Soft red winter wheat (SRWW) cultivar AGS 2038 has a high level of seedling and adult plant leaf rust (LR) resistance. To map and characterize LR resistance in AGS 2038, a recombinant inbred line (RIL) population consisting of 225 lines was developed from a cross between AGS 2038 and moderately resistant line UGA 111729. The parents and RIL population were phenotyped for LR response in three field environments at Plains and Griffin, GA, in the 2017–2018 and 2018–2019 growing seasons, one greenhouse environment at the adult‐plant stage, and at seedling stage. The RIL population was genotyped with the Illumina iSelect 90K SNP marker array, and a total of 7667 polymorphic markers representing 1513 unique loci were used to construct a linkage map. Quantitative trait loci (QTL) analysis detected six QTL, QLr.ags‐1AL, QLr.ags‐2AS, QLr.ags‐2BS1, QLr.ags‐2BS2, QLr.ags‐2BS3, and QLr.ags‐2DS, for seedling and adult plant LR resistance. Of these, the major adult plant leaf rust resistance QTL, QLr.ags‐1AL, was detected on all field and greenhouse adult plant tests and explained up to 34.45% of the phenotypic variation. QLr.ags‐1AL, tightly flanked by IWB20487 and IWA4022 markers, was contributed by AGS 2038. Molecular marker analysis using a diagnostic marker linked to Lr59 showed that QLr.ags‐1AL was different from Lr59, the only known LR resistance gene on 1AL. Therefore, the QTL was temporarily designated as Lr2K38. Lr2K38‐linked marker IWB20487 was highly polymorphic among 30 SRWW lines and should be useful for selecting the Lr2K38 in wheat breeding programs.

中文翻译：

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定位于小麦1AL染色体的成年植物叶片防锈新基因Lr2K38

柔软的红色冬小麦（SRWW）品种AGS 2038具有很高的幼苗抗性和成年植物叶锈病（LR）抗性。为了定位和表征AGS 2038中的LR抗性，从AGS 2038和中度抗性品系UGA 111729的杂交中形成了由225个品系组成的重组近交系（RIL）群体。在三个视野中对亲本和RIL群体进行了LR反应表型在2017-2018年和2018-2019年生长季节，在乔治亚州普莱恩斯和格里芬的环境中，在成年植物阶段和幼苗阶段建立一种温室环境。使用Illumina iSelect 90K SNP标记阵列对RIL群体进行基因分型，并使用代表7个多态性标记（代表1513个唯一位点）的共7667个多态性标记来构建连锁图。数量性状基因座（QTL）分析检测到六个QTL，QLr.ags-1AL，QLr.ags-2AS，QLr.ags-2BS1，QLr.ags-2BS2，QLr.ags-2BS3和QLr.ags-2DS，用于幼苗和成年植物的LR抗性。其中，在所有田间和温室成年植物试验中均检测到主要的成年植物叶片抗锈性QTL QLr.ags-1AL，可解释多达34.45％的表型变异。QLr.ags-1AL与IWB20487和IWA4022标记紧密相邻，由AGS 2038贡献。使用与Lr59连锁的诊断标记进行的分子标记分析表明QLr.ags-1AL与Lr59不同，是1AL上唯一已知的LR抗性基因。因此，QTL被临时指定为Lr2K38。Lr2K38连锁的标记IWB20487在30条SRWW品系中具有高度多态性，对于在小麦育种计划中选择Lr2K38很有用。