Characterization of Common Wheat Translocations Carrying Leaf Rust Resistance Genes from Alien Species

Abstract

Leaf rust caused by Puccinia triticina Erikss may inflict significant yield losses in wheat; however, can be controlled by breeding for increased host resistance. In earlier studies, effective, resistance has been transferred to common wheat from the wild relatives Thinopyrum ponticum (Lr19), Aegilops sharonensis (Lr56), Ae. peregrina (Lr59), and Ae. neglecta (Lr62). Each translocation was subsequently re-engineered by the induction of homoeologous chromosome exchanges with a normal wheat chromosome to remove unneeded alien chromatin. For each gene the 3-8 most promising recombinants that retained the least linkage drag, but could not be differentiated, were identified. This study employed physical and genetic mapping in conjunction with molecular markers and genomic in situ hybridization to identify those recombinants that are best suited for breeding. For each gene, the recombinant with the least alien chromatin that also appeared to be fully compensating was identified and marker loci suitable for marker-assisted selection were suggested.