PEAR DIVERSITY IN NORTHWESTERN SPAIN DETERMINED BY MICROSATELLITES

Abstract

Spain is among the ten largest European pear (Pyrus communis L.) producers. Pear production is based on foreign cultivars. However, local cultivars are still grown in the old orchards in northwestern Spain. Between 1978 and 1981, the Centro de Investigaciones Agrarias de Mabegondo (CIAM, Xunta de Galicia) in Galicia established a germplasm bank in order to conserve genetic resources including local pear cultivars. In the current study, 216 accessions from CIAM and 19 commercial Pyrus cultivars were analyzed and compared with 15 polymorphic microsatellites, each marker being located at a different locus. We differentiated 130 genotypes out of the 216 accessions of the germplasm bank (60%). 86 of the accessions were duplications due to clonality (40%). A total of eight accessions of the germplasm bank (4%) were identified as commercial cultivars, those being: 'Castell' (1), 'Mantecosa Hardy' (2), 'Roma' (1), 'Blanquilla' (1) and 'Williams' (3). 33 genotypes were identified as duplications, some homonyms and synonyms that had not previously been described. The most frequent duplicated genotypes were those corresponding to 'Mantecosa', 'Urraca', 'Sevillana' and 'Donguindo', all of them previously reported as important pear cultivars in northwestern Spain. These results will allow the correct identification of unique genotypes and elimination of duplications in the CIAM germplasm bank. Some of these local cultivars can be used to diversify Spanish production.