Genetic analysis and localization of loci controlling leaf rust resistance of Triticum aestivum × Triticum timopheevii introgression lines

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Introgressive lines resulting from crossing common wheat Triticum aestivum with the tetraploid T. timopheevii are characterized by effective resistance to leaf rust caused by Puccinia triticina Eriks. Molecular analysis using 350 specific simple sequence repeat (SSR) markers determined localization of the T. timopheevii genome in chromosomes 1A, 2A, 2B, 5A, 5B, and 6B. A population of F2 offspring of crossing hybrid line 842-2 with common wheat cultivar Skala was obtained for mapping the loci controlling leaf rust resistance. Analysis of association of phenotypic and genotypic data by means of simple interval mapping (SIM) and composite interval mapping (CIM) has shown that the resistance of adult plants is determined by two loci in chromosomes 5B and 2A. The major locus QLr.icg-5B, transferred from T. timopheevii chromosome 5G mapped to the interval of microsatellite loci Xgwm408-Xgwm1257 controls 72% of the phenotypic variance of the trait. The other, minor locus QLr.icg-2A located to chromosome 2A at a distance of 10 cM from Xgwm312 accounts for 7% of the trait expression. Microsatellite markers located near these loci may be used for controlling the transfer of agronomically valuable loci when new lines and cultivars are created.

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