Submitted to: International Congress of Plant Pathology Abstracts and Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 10/9/2007
Publication Date: N/A
Technical Abstract: Crown rust, caused by Puccinia coronata f. sp. Avenae, is the most damaging disease of oat (Avena avenae L.). Historically, crown rust has been controlled by identifying and employing various major genes. The resistance gene Pc58, originally identified in ‘TAM O-301’, has been widely effective. Recent studies have established that Pc58 is a complex of genes mapping to 3 loci: two tightly linked genes, Pc58a and Pc58c, and a third loosely linked gene (Pc58b). The objectives of the current study were two determine the effectiveness of each gene in the Pc58 complex and develop single nucleotide polymorphism (SNP) markers linked to the effective genes. Parents and Ogle/TAM O-301 (OT) mapping population (MP) lines were grown under intense natural disease pressure in Louisiana and Texas over two years, and in plots in Canada inoculated with a composite of Canadian races. Diseased leaf area (DLA) and infection types were measured for parents and individual lines, and for groups of lines containing Pc58a and Pc58b singly or other combinations of the three genes. OT MP lines containing Pc58a had significantly lower (2.5X) DLA than all other lines. Additionally, DLA of lines containing Pc58b alone or when not in combination with Pc58a did not differ from the susceptible parent. Since Pc58a significantly reduced crown rust in all 5 field experiments, candidate SNP markers were developed from tightly linked restriction fragment length polymorphism (RFLP) probes flanking Pc58a. Work is underway to validate the SNP markers for use in marker-assisted introgression of Pc58a into new breeding materials.