Characterization and Mapping of a Crown Rust Resistance Gene Complex(Pc58) in TAM O‐301

Crown rust of cultivated oat ( Avena sativa L.) caused by Puccinia coronata Corda f. sp. avenae Eriks, causes yield loss, reduction in test weight, and increased lodging. Genetic resistance is the most desirable method to control the disease. ‘TAM O‐301’, a cultivar released by the Texas A&M oat‐breeding program in 1973, has crown rust resistance, subsequently named Pc58 . The main objectives of this study were to characterize Pc58 in TAM O‐301 using an F 6:7 recombinant inbred (RI) population of the ‘Ogle’ × TAM O‐301 cross and to map the Pc58 resistance. Six crown rust isolates, avirulent on TAM O‐301 and virulent on Ogle, were used to test the parents and RI population. Genetic analyses of the segregation data to each of the six isolates indicated that the resistance was conditioned by three genes within a 41.0‐cM region. The resistance genes were mapped to linkage groups OT32 and OT33 in the published molecular linkage map of Ogle × TAM O‐301. This research has provided new information on the Pc58 resistance gene complex that should facilitate new marker and germplasm development.