Plant Genome IV Conference Plant Genome IV Conference
Crown rust, caused by Puccinia coronata, is the major fungal disease of oat. Resistance to crown rust is usually, but not always, controlled by single dominant genes in hexaploid oat (Avena sativa). We have examined seventy recombinant inbred lines derived from a cross between A. byzantina cv Kanota and A. sativa cv Ogle that differ in their responses to the two crown rust isolates, PC54 and PC59. Analysis of rust infection type data indicates that resistance in this population is not conferred by a single gene. Further analysis suggests that resistance is due to two major unlinked loci which are located on linkage groups 4 and 13 of the molecular map developed from this cross. Additionally, resistance to the two isolates could not be separated genetically, and so both complementary loci appear to be required for resistance to either isolate.