ORIGINAL PAPER P. This Æ A. Jung Æ P. Boccacci Æ J. Borrego Æ R. Botta L. Costantini Æ M. Crespan Æ G. S. Dangl Æ C. Eisenheld F. Ferreira-Monteiro Æ S. Grando Æ J. Iba´n˜ ez T. Lacombe Æ V. Laucou Æ R. Magalha˜es C. P. Meredith Æ N. Milani Æ E. Peterlunger Æ F. Regner L. Zulini Æ E. Maul Development of a standard set of microsatellite reference alleles for identification of grape cultivars Received: 9 July 2003 / Accepted: 16 June 2004 / Published online: 30 September 2004 Ó Springer-Verlag 2004 Abstract In order to investigate the comparability of microsatellite profiles obtained in different laboratories, ten partners in seven countries analyzed 46 grape culti- vars at six loci (VVMD5, VVMD7, VVMD27, VVS2, VrZAG62, and VrZAG79). No effort was made to standardize equipment or protocols. Although some partners obtained very similar results, in other cases different absolute allele sizes and, sometimes, different relative allele sizes were obtained. A strategy for data comparison by means of reference to the alleles detected in well-known cultivars was proposed. For each marker, each allele was designated by a code based on the name of the reference cultivar carrying that allele. Thirty-three cultivars, representing from 13 to 23 alleles per marker, were chosen as references. After the raw data obtained by the different partners were coded, more than 97% of the data were in agreement. Minor discrepancies were attributed to errors, suboptimal amplification and visu- alization, and misscoring of heterozygous versus homozygous allele pairs. We have shown that coded microsatellite data produced in different laboratories with different protocols and conditions can be com- pared, and that it is suitable for the identification and SSR allele characterization of cultivars. It is proposed that the six markers employed here, already widely used, be adopted as a minimal standard marker set for future L. Costantini Æ S. Grando Laboratory of Molecular Genetics, Istituto Agrario S. Michele all’ Adige, Via Mach, 38010 Trento, Italy M. Crespan Æ N. Milani Sezione Ampelografia e Miglioramento Genetico, Istituto Sperimentale per la Viticoltura, via Casoni 13/A, 31058 Susegana (Treviso), Italy G. S. Dangl Æ C. P. Meredith Department of Viticulture and Enology, University of California, Davis, CA 95616, USA C. Eisenheld Æ F. Regner Department for Grapevine Breeding, HBLA u. BA Klosterneuburg, 2103 Langenzersdorf, Rehgraben 2, Austria F. Ferreira-Monteiro Instituto Portugues de Viticultura e Enologia (IPVE), Rua Eng. Frederico Ulrich 2650, 4470-605 Maia, Portugal R. Magalha˜es Instituto de Ciencias Biomedicas de Abel Salazar (ICBAS), Universidade do Porto, Largo Prof. Abel Salazar, 2, 4099-003 Porto, Portugal E. Peterlunger Æ L. Zulini Department of Crop Production and Agricultural Technology, University of Udine, Via delle Scienze 208, 33100 Udine, Italy Communicated by C. Mo¨llers Electronic Supplementary Material Supplementary material is available for this article at http://dx.doi.org/10.1007/s00122-004- 1760-3 P. This (&) Æ T. Lacombe Æ V. Laucou Laboratory of Grape Genetics, UMR Diversite´ et Ge´nomes des Plantes Cultive´es (DGPC), Institut National de la Recherche Agronomique (INRA), 2, place P. Viala, 34060 Montpellier, France E-mail: this@ensam.infra.fr Tel.: +33-499612539 Fax: +33-499612064 A. Jung Æ E. Maul Federal Centre of Breeding Research on Cultivated Plants, Institute for Grapevine Breeding Geilweilerhof, 76833 Siebeldingen, Germany P. Boccacci Æ R. Botta Centro di Studio per il Miglioramento Genetico e la Biologia della Vite–CNR, Dipartimento di Colture Arboree, Universita` degli Studi di Torino, Via Leonardo da Vinci 44, 10095 Grugliasco, Italy J. Borrego Æ J. Iba´n˜ez Instituto Madrilen˜o de Investigacio´n Agraria y Alimentaria, Finca ‘‘El Encı´n’’, Apartado 127, 28800 Alcala´ de Henares, Madrid, Spain Theor Appl Genet (2004) 109: 1448–1458 DOI 10.1007/s00122-004-1760-3