DEVELOPMENT OF A SCAR MARKER LINKED TO THE I-GENE IN COMMON BEAN

Two 24-mer SCAR primers (SW13) were developed from a previously identi fied 10-mer RAPD primer (OW13(690)) linked to the I gene, which condit ions resistance to bean common mosaic virus (BCMV) in common bean. Lin kage between SW13 and the I gene was tested in three F-2 populations s egregating 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(6 90) RAPD marker. Using different heat-stable DNA polymerases, SW13 amp lified a single 690-bp fragment linked to the I gene that more consist ently permitted the identification of resistant plants. In addition, t he presence of the I gene was detected using SW13 in genotypes origina ting from different gene pools of Phaseolus vulgaris L., indicating a broad utility of this marker for bean breeding programs.