SummaryHexaploid and diploid plum cultivars from the collection of Aula Dei (Zaragoza, Spain) were examined by means of RAPDs (random amplified polymorphic DNAs). A high degree of polymorphism was detected and it was possible to distinguish all 31 genotypes by combining the RAPDs patterns of three primers: AD16, AD14 and B1. Genotype-specific RAPDs and fragment patterns were found in many cultivars. These patterns are of potential use for cultivar identification and for detection of duplications in germplasm collections. Cluster analysis and PCA based on similarity coefficients between single genotypes were performed. The dendrogram and PCA plot reflected dispersed groupings without clear agglomerations within the European plum cultivars. The presence of high genetic variability combined with intensive recombination due to outcrossing, hybridizations between different Prunus species, sexual propagation and interchange of breeding material can explain this finding. However, in some cases, relationships amo...