to multiple races of U. appendiculatus, indicating that they are organized in clusters of race-specific genes. Uromyces appendiculatus (Pers.) Unger, the causative fungus of DNA amplification of near isogenic lines (NILs) rust in common beans (Phaseolus vulgaris L.), consists of many patho- (Paran et al., 1991; Martin et al., 1991) or of contrasting types or pathogenic races. Cultivar Ouro Negro is resistant to most DNA bulks from segregating populations (Michelmore pathotypes detected in Brazil in the last few decades. We attempted et al., 1991) can be used to detect RAPD (Williams et to identify molecular markers linked to a rust resistance gene block 111 3 Ouro Negro were determined. SCARBA08 and SCARF10 were determined to be 4.3 6 1.2 and 6.0 6 1.3 centimorgans (cM) al., 1995). In some cases, the application of these mark- from the rust resistance locus, respectively. These markers are being ers has been restricted to the laboratories where they used in combination with other markers for resistance to rust, anthrac- were identified because of reproducibility problems nose, and angular leaf spot previously identified in our laboratory to with this technique (Kesseli et al., 1992; Weden et al., aid the indirect selection of desirable plants in segregating populations 1992). Sequence characterized amplified regions (Kes- in which Ouro Negro has been used as donor parent.