Fine Mapping of the Genomic Region Carrying Linked Rust Resistance Genes Lr52 and Yr47 in Common Wheat

Stripe rust and leaf rust of wheat pose a serious threat to the world wheat production. Genetically linked resistance genes Yr47 and Lr52 are effective against prevalent Australian, Indian, Canadian and US pathotypes of Puccinia striiformis f. sp. tritici and P. triticina, respectively. Previously, Yr47 and Lr52 were mapped in the short arm of chromosome 5B in two F3 populations (AUS28183/AUS27229 and AUS28187/AUS27229) derived from the Watkins collection of landraces. The map order: gwm234-10.2cM - Lr52 - 3.3cM – Yr47 – 9.6cM - cfb309 was reported. The F3 population AUS28183/AUS27229 was advanced to produce a F6 recombinant inbred line (RIL) population. This study aimed to identify closely linked markers for these resistance genes using the F6 RIL population through saturation of the region using SSR markers designed from survey sequence scaffolds representing the orthologous region in Brachypodium distachyon, gene specific markers from expressed sequence tags (ESTs) located in the 5BS6-0.81-1.00 deletion bin and RGA contigs from chromosome 5BS. Selective genotyping was carried out using a 90K iSelect SNP array. KASPar markers were designed from linked SNP sequences. Markers more closely linked with Yr47 and Lr52 have been identified.