Leaf rust caused by Puccinia triticina Erikss. (Pt) is the most widely distributed and important wheat disease worldwide. The objective of the present study was to determine the frequency of Iranian Pt races, their virulence to key resistance genes and map quantitative trait loci (QTL) for resistance to different Pt races from 185 globally diverse wheat genotypes using a genome-wide association study (GWAS) approach. The virulence pattern of the 33 Pt isolates from various wheat-growing areas of Iran on 55 wheat differentials showed that the FKTPS and FKTTS were relatively frequent pathotypes among the 18 identified races. The weighted average frequency of virulence on the resistance genes Lrb, Lr3bg, Lr14b, Lr16, Lr24, Lr3ka, Lr11 and Lr20 were high (> 90%). However, low virulence on the resistant genes Lr2a, Lr9, Lr19, Lr25, Lr28 and Lr29 indicates that these genes are still effective against the pathogen population in Iran at present. GWAS on a panel of 185 wheat genotypes against 10 Pt races resulted into 62 significant marker-trait associations (MTAs) belonged to 34 quantitative trait loci (QTL) across 16 chromosomes. Among them, 10 QTLs on chromosomes 1A, 1B, 3B, 3D, 4A, 6D, 7A and 7D were identified as potential novel QTLs, of which four QTLs (QLr.iau-3B-2, QLr.iau-7A-2, QLr.iau-7A-3 and QLr.iau-7D-2) are more interesting, as they are associated with resistance to two or more Pt races. The known and novel QTLs associated with different Pt races found here, can be used in future wheat breeding programs to recombine different loci for durable resistance against leaf rust races.

Puccinia triticina Erikss引起的叶锈病。(Pt) 是世界范围内分布最广、最重要的小麦病害。本研究的目的是确定伊朗 Pt 种族的频率、它们对关键抗性基因的毒力，并使用全基因组关联研究绘制对来自 185 种全球不同小麦基因型的不同 Pt 种族的抗性数量性状基因座 (QTL)（ GWAS）方法。来自伊朗不同小麦产区的33 株Pt分离株对 55 个小麦差异的毒力模式表明，FKTPS 和 FKTTS 在 18 个已鉴定的小种中是相对常见的致病型。耐药基因Lrb、Lr3bg、Lr14b、Lr16的加权平均毒力频率, Lr24 , Lr3ka , Lr11和Lr20都很高 (> 90%)。然而，抗性基因Lr2a、Lr9、Lr19、Lr25、Lr28和Lr29的低毒力表明这些基因目前对伊朗的病原体种群仍然有效。针对 10 个Pt种族的 185 个小麦基因型组的 GWAS 产生了 62 个显着的标记性状关联 (MTA)，属于 16 条染色体上的 34 个数量性状位点 (QTL)。其中，染色体1A、1B、3B、3D、4A、6D、7A和7D上的10个QTL被鉴定为潜在的新型QTL，其中4个QTL（QLr.iau-3B-2、QLr.iau-7A-2、QLr.iau-7A-3和QLr.iau-7D-2 ）更有趣，因为它们与对两个或多个Pt种族的抵抗力有关。此处发现的与不同Pt小种相关的已知和新型 QTL可用于未来的小麦育种计划，以重组不同的基因座以获得对叶锈病小种的持久抗性。