Department of Plant Pathology, University of Minnesota, 495 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, USA.
Phytopathology. 2013 Jun;103(6):600-9. doi: 10.1094/PHYTO-10-12-0271-R.
Septoria speckled leaf blotch (SSLB) is a sporadic but important disease of barley (Hordeum vulgare) in the Upper Midwest region of the United States and Prairie Provinces of Canada that is caused primarily by Septoria passerinii. Most of the widely grown cultivars in the region are susceptible to the disease. To identify and map SSLB resistance loci in U.S. barley breeding germplasm, we employed an association mapping approach using 3,840 breeding lines and cultivars and nearly 3,000 single-nucleotide polymorphism markers previously mapped to the seven barley chromosomes. SSLB infection responses (IRs) were assayed on seedling plants in the greenhouse using a 0-to-5 scale. From the analysis of four yearly panels consisting of 960 lines each, four quantitative trait loci (QTL) for SSLB resistance were identified: one on chromosome 1H (Rsp-qtl-H_12_31144), one on chromosome 3H (Rsp-qtl-3H_12_31488), and two on chromosome 6H (Rsp-qtl-6H_11_21032 and Rsp-qtl-6H_11_10064). Individual resistance QTL reduced the mean IR from 9 to 38% compared with lines lacking any resistance alleles. However, the combination of all four resistance QTL together reduced the mean IR by 83%. The markers found associated with these QTL will be valuable for programs utilizing marker-assisted selection for SSLB resistance.
条斑叶枯病（SSLB）是美国中西部地区和加拿大草原省份一种偶发性但重要的大麦病害，主要由叶点霉菌引起。该地区种植的大多数广泛栽培的品种都容易受到该病的影响。为了鉴定和定位美国大麦育种种质中的条斑叶枯病抗性基因座，我们采用了一种关联作图方法，利用 3840 条育种系和品种以及近 3000 个先前映射到 7 条大麦染色体的单核苷酸多态性标记。在温室中使用 0 到 5 的等级对幼苗植物进行条斑叶枯病感染反应（IR）测定。从包含 960 条线的四个年度面板的分析中，鉴定出了四个条斑叶枯病抗性的数量性状基因座（QTL）：一个位于 1H 染色体上（Rsp-qtl-H_12_31144），一个位于 3H 染色体上（Rsp-qtl-3H_12_31488），两个位于 6H 染色体上（Rsp-qtl-6H_11_21032 和 Rsp-qtl-6H_11_10064）。与缺乏任何抗性等位基因的系相比，单个抗性 QTL 将平均 IR 降低了 9%至 38%。然而，将所有四个抗性 QTL 组合在一起，平均 IR 降低了 83%。与这些 QTL 相关的标记将对利用标记辅助选择进行条斑叶枯病抗性的项目具有重要价值。
