Inheritance of crown rust resistance in four accessions of Avena sterilis L

Genetic resistance in common oat, Avena sativa L., provides an effective means of controlling crown rust, caused by Puccinia coronata Cda. f. sp. avenae Eriks. Four Avena sterilis L. accessions (IB 1487, IB 2402, IB 2465, and IB 3432) were selected for a genetic study based on low disease reaction to 15 isolates of crown rust and ease of hybridization to common oat. Crosses were made to determine the mode of inheritance of the resistance in each accession and to detect the linkage relationship of the resistance genes with several known crown-rust resistance genes. The accessions were crossed to the susceptible common oat line Rodney 0, intercrossed among themselves, and crossed to six Lines, each with a single gene for crown rust resistance: Pc38, Pc56, Pc58, Pc61, Pc63, and Pc68. In a greenhouse, the F-2 populations were evaluated for seedling reaction after inoculation of the first leaf with crown rust isolate CR 13. Each accession had a single incompletely dominant or dominant gene conferring resistance, and genes were designated as Gene A in IB 1487, Gene B in IB 2402, Gene C in IB 2465, and Gene D in IB 3432. Gene A is allelic or closely linked to Pc56. Genes B and C are allelic or closely linked to Pc68. Having not been described previously, Gene D may be a useful addition to existing germplasm.