Mapping Oat Crown Rust Resistance Gene Confirms Association with .

Molecular mapping of crown rust resistance genes is important to effectively utilize these genes and improve breeding efficiency through marker-assisted selection. is a major race-specific crown rust resistance gene initially identified in the wild hexaploid oat in the early 1970s. This gene was transferred to cultivated oat () and has been used as a differential for identification of crown rust races since 1974. Previous research identified an association between virulence to and , a crown rust resistance gene in the varieties 'Kame' and 'Morton'. This study was undertaken to reveal the relationship between and was studied in the crosses 'AC Morgan'/ and 'Kasztan'/, where is the differential line carrying F progenies and F families of both populations were inoculated with the crown rust isolate CR258 (race NTGG) and single gene segregation ratios were observed. SNP markers for were tested on these populations and linkage maps were generated. In addition, 17 newly developed SNP markers identified from genotyping-by-sequencing (GBS) data were mapped in these two populations, plus another three populations segregating for or and mapped to the same location of Mrg08 (chromosome 12D) of the oat chromosome-anchored consensus map. These results strongly suggest that and are the same resistance gene, but allelism (, functionally different alleles of the same gene) or tight linkage (, two tightly linked genes) cannot be ruled out based on the present data.