Development of a SCAR marker linked to the I gene in common bean.

Two 24-mer SCAR primers (SW13) were developed from a previously identified 10-mer RAPD primer (OW13(690)) linked to the I gene, which conditions resistance to bean common mosaic virus (BCMV) in common bean. Linkage between SW13 and the I gene was tested in three F2 populations segregating for both SW13 and the I gene: N84004/Michelite (1.0 +/- 0.7 cM), Seafarer/UI-114 (1.3 +/- 0.8 cM), and G91201/Alpine (5.0 +/- 2.2 cM). SW13 proved to be more specific and reproducible than the OW13(690) RAPD marker. Using different heat-stable DNA polymerases, SW13 amplified a single 690-bp fragment linked to the I gene that more consistently permitted the identification of resistant plants. In addition, the presence of the I gene was detected using SW13 in genotypes originating from different gene pools of Phaseolus vulgaris L., indicating a broad utility of this marker for bean breeding programs.