Genetic diversity in a collection of European pear (Pyrus communis) cultivars determined with SSR markers chosen by ECPGR

Simple sequence repeat (SSR) markers are increasingly being used to confirm the identification of accessions in plant collections and/or to quantify their relatedness. However, the possibility to compare SSR data in different databases, is dependent on the use of identical SSR loci. Therefore, a standard set of 17 SSR loci was recently appointed by the European Cooperative Program for Plant Genetic Resources (ECPGR) for the screening of pear accessions. Here, we report the results from using 10 of these loci to fingerprint a total of 86 samples from Swedish pear collections including 49 mandate (heritage) cultivars, and 8 reference genotypes from Brogdale. The ability to compare our data with previously obtained data from fingerprinting the Brogdale collection with the same loci, allowed us to verify the labelling of some cultivars as well as to detect several synonyms and erroneous labellings. Obvious cases of mislabelling affected 14 of the analysed cultivars, i.e., 29%. A principal coordinates (PCO) analysis indicated that a loosely defined group of old Swedish cultivars might have an ancestry that differs from that of the new Swedish cultivars and from most of the foreign cultivars. (c) 2012 Elsevier B.V. All rights reserved.