Characterization of PmBN418, a wheat powdery mildew resistance gene on the rye 1RS chromosome arm

Abstract Powdery mildew, caused by Blumeria graminis f . sp . tritici ( Bgt ), is a disease of global importance, and new powdery mildew resistance genes that can be directly used in cultivar development are urgently needed. A recombinant inbred line population from ‘CI 17884’ × ‘Bainong 418’ was genotyped using single nucleotide polymorphism markers generated from genotyping‐by‐sequencing, and evaluated for responses to Great Plains Bgt isolates OKS(14)‐B‐3‐1 and NEI‐1‐3 . Genetic mapping identified a powdery mildew resistance gene, designated PmBN418 , on a 1BL.1RS translocation segment in Bainong 418. Given that PmBN418 conferred resistance to Bgt isolates virulent to Pm8 that resides on the chromosome arm 1RS translocated from rye ( Secale cereale L.) cv. ‘Petkus’, PmBN418 is either a new gene or a new allele of Pm8 . Phenotypic and genomic data analyses indicated segregation distortion of the powdery mildew resistance gene due to reduced transmission of the wheat ( Triticum aestivum L.)–rye 1BL.1RS translocation segment from Bainong 418, while the wheat– Triticum speltoides translocation segment 7S#1 in CI 17884 was preferentially transmitted. Bainong 418, a high‐yielding cultivar with good resistance to several U.S. Bgt isolates, is a useful resistance source for wheat breeding, and the availability of the Kompetitive Allele Specific PCR (KASP) marker KASP‐1RS‐1 makes marker‐assisted introgression of PmBN418 into locally adapted cultivars feasible.