Abstract
Accurate identification of apple cultivars is an important prerequisite for the management of germplasm collections. Apart from phenotypic traits, microsatellite DNA markers are being widely employed for cultivar characterisation. In the present study, 28 accessions of Malus × domestica from six European germplasm collections were investigated. These were assigned to ten different genotypes based on an initial study of 14 microsatellite loci. To rule out the possibility that this number of markers was too low to differentiate between closely related cultivars, 34 additional loci were analysed. The extension of the set of microsatellite markers to a total of 48, however, did not result in an increased resolution among accessions previously assigned to eight genotypes, while in two cases mismatches were found at 2 of the 48 loci. The results obtained are discussed, also with regard to some common genotyping errors.