Late blight (LB), caused by the oomycete Phytophthora infestans (Mont.) de Bary, is one of the most devastating diseases of tomato (Solanum lycopersicum L.) and potato (S. tuberosum L.) worldwide. The importance of LB on tomato has increased due to the occurrence of aggressive and fungicide‐resistant clonal lineages of P. infestans. Consequently, identification and characterization of new sources of genetic resistance to LB has become a priority in tomato breeding. Previously, we reported accession PI 163245 as a promising source of highly heritable LB resistance for tomato breeding. The purpose of this study was to identify and map quantitative trait loci (QTLs) associated with LB resistance in this accession using a trait‐based marker analysis (a.k.a. selective genotyping). An F₂ mapping population (n = 560) derived from a cross between a LB‐susceptible tomato breeding line (Fla. 8059) and PI 163245 was screened for LB resistance, and the most resistant (n = 39) and susceptible (n = 35) individuals were selected for genotyping. Sequencing and comparison of the reduced representation libraries (RRLs) derived from genomic DNA of the two parents resulted in the identification of 33,541 putative single nucleotide polymorphism (SNP) markers, of which, 233 genome‐wide markers were used to genotype the 74 selected F₂ individuals. The marker analysis resulted in the identification of four LB resistance QTLs conferred by PI 163245, located on chromosomes 2, 3, 10, and 11. Research is underway to develop near‐isogenic lines (NILs) for fine mapping the QTLs and develop tomato breeding lines with LB resistance introduced from PI 163245.

中文翻译：

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番茄登录号PI 163245中晚疫病抗性定量性状位点的鉴定与定位。

晚疫病（LB）是由茂盛的疫霉疫霉（Monty）de Bary引起的，是世界范围内最具破坏力的番茄（Solaum lycopersicum L.）和马铃薯（S. tuberosum L. ）的病害之一。LB的番茄上的重要性已经由于增加至攻击性和耐杀菌剂-克隆谱系的发生致病疫霉。因此，鉴定和鉴定对LB的新遗传抗性来源已成为番茄育种的优先领域。此前，我们报道了PI 163245号是番茄育种中高度可遗传的LB抗性的有希望的来源。这项研究的目的是使用基于性状的标记分析（又名选择性基因分型）来鉴定和定位与该抗性相关的定量性状基因座（QTL）。从LB易感番茄育种系（Fla。8059）和PI 163245之间的杂交中获得的F ₂作图种群（n = 560）进行了LB抗性筛选，最抗性（n = 39）和易感性（n= 35）选择了个体进行基因分型。对来自两个亲本的基因组DNA的简化表示文库（RRL）进行测序和比较后，鉴定出33,541个推定的单核苷酸多态性（SNP）标记，其中233个全基因组标记用于对74个选定的F进行基因分型₂个人。通过标记分析，鉴定了PI 163245赋予的4个LB抗性QTL，它们位于2、3、10和11号染色体上。目前正在研究开发近等基因系（NIL），以对QTL进行精细定位并进行番茄育种。由PI 163245引入的具有LB电阻的线路。