|Xin, Yu - IOWA STATE UNIVERSITY|
Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: November 18, 1997
Publication Date: N/A
Technical Abstract: <i>Puccinia coronata Corda</i>f. sp. <i>avenae </i> Eriks., the causal agent of crown rust, is the most important fungal pathogen of cultivated oat. The <i>Pca</i> crown-rust resistance-gene cluster was identified by analyzing a diploid <i>Avena </i> recombinant inbred (R1) population generated by crossing the crown-rust resistant <i>A. strigosa</i> accession nC.I. 3815 with the susceptible <i>A. wiestii</i> accession C.I. 1994. To further determine the composition of the <i>Pca</i> locus, we analyzed seven F2 backcross (BC1F2) populations between the susceptible parent C.I. 1994 and seven key R1 lines with putative recombination break points. These BC1F2 populations were tested with diagnostic crown-rust isolates. As a result of these analyses, multiple specificities of the <i>Pca</i> locus were demonstrated to be controlled by a series of closely linked genes within the <i>Pca</i> cluster. A saturated AFLP map was constructed for diploid <i>Avena</i> and three AFLP markers were found to be closely linked to the <i>Pca<i> cluster. Allele-specific PCR primers were designed for the Agx4 marker that co-segregated with the R202 specificity within <i>Pca</i>. The Agx4 PCR primers will be valuable to study the evolution of the <i>Pca </i> cluster and in the marker-assisted breeding of <i>Avena</i>.