Wild wheat species Aegilops peregrina (UpUpSpSp), harbours resistance to various diseases including leaf rust and stripe rust. Inheritance studies in a recombinant inbred line population of wheat-Ae. peregrina introgression line IL pau16061 revealed the transfer of a single major dominant gene conditioning all stage resistance, herein temporarily designated as LrAp. Genomic in situ hybridisation of IL pau16061, resistant and susceptible RILs with U- and S-genome DNA probes confirmed that the introgression with leaf rust resistance is from the Up genome of Ae. peregrina. Fluorescence in situ hybridisation using chromosome specific probes identified Up genome introgression to be on the long arm of wheat chromosome 6B. To genetically map LrAp, bulked segregant analysis was combined with resistance gene enrichment sequencing (MapRenSeq). Five nucleotide binding leucine-rich repeat contigs distinguished resistant and susceptible bulks and single nucleotide polymorphism (SNP) markers from these contigs co-segregated with LrAp. All five RenSeq NB_ARC contigs showed identity with the long arm of wheat chromosome 6B confirming the introgression on 6BL which we propose is a compensating translocation from Ae. peregrina chromosome 6UpL due to homoeology between the alien and wheat chromosomes. The SNP markers developed in this study will aid in cloning and marker assisted gene pyramiding of LrAp.

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A wild non-progenitor species from wheat tertiary gene pool Aegilops peregrina accession pau3519 (UUSS) was used for introgression of leaf rust and stripe rust resistance in bread wheat. It was crossed and backcrossed with hexaploid wheat line Chinese Spring Ph I to develop two homozygous BC 2 F 6 wheat-Ae. peregrina introgression lines (ILs) viz. IL pau16058 and IL pau16061 through induced homoeologous recombination. Homozygous lines were screened against six Puccinia triticina and two Puccinia striiformis f. sp. tritici pathotypes at the seedling stage and a mixture of prevalent pathotypes of both rust pathogens at the adult plant stage. IL pau16061 showed resistance to leaf rust only while IL pau16058 was resistant to both leaf and stripe rust pathotypes throughout plant life. Molecular characterization of these ILs aided in defining the introgressed regions. Identification of linked markers with advance genomic technologies will aid in marker assisted pyramiding of alien genes in cultivated wheat background.

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A wild non-progenitor species from wheat tertiary gene pool Aegilops peregrina accession pau3519 (UUSS) was used for introgression of leaf rust and stripe rust resistance in bread