Rust resistance in wheat: genetic analysis and molecular mapping

Abstract

Breeding for rust resistance in wheat relies on detailed understanding and availability of existing genetic diversity for rust resistance among global germplasm and knowledge of pathotypic variation among rust pathogens. This study involved assessment of genetic diversity for stem rust resistance in an international wheat nursery ZWB14, inheritance of stripe rust resistance in a common wheat landrace Aus27881 and molecular mapping of stripe rust resistance in genotype ZIZ13:69 imported from International Centre for Agricultural Research in the Dry Areas (ICARDA). All stage resistance (ASR) genes Sr8a, Sr17, Sr24, Sr30, Sr31 and Sr38 and adult plant resistance (APR) genes Sr2, Sr57 and Sr58 were present either singly or in different combinations in entries of ZWB14. Some entries were observed to carry additional uncharacterised resistance. Tri-genic inheritance of stripe rust resistance in Aus27881 was observed. Genotyping with Yr34 and Yr29 linked markers demonstrated the presence of these genes in Aus27881. Third locus that conditioned APR in Aus27881 appears to be new and needs further characterisation. Genotype ZIZ13:69 was demonstrated to carry ASR gene Yr1 and APR gene Yr29 based on greenhouse tests and marker genotyping, respectively. The targeted genotyping by sequencing (tGBS) assay of a set of RILs lacking Yr29 detected a new quantitative trait locus (QTL) on the long arm of chromosome 7D.