Molecular Ecology Notes (2005) 5, 934–937 doi: 10.1111/j.1471-8286.2005.01121.x © 2005 Blackwell Publishing Ltd Blackwell Publishing, Ltd. PRIMER NOTE Characterization and evaluation of microsatellite loci in European hazelnut (Corylus avellana L.) and their transferability to other Corylus species P. BOCCACCI,* A. AKKAK,* N. V. BASSIL,† S. A. MEHLENBACHER‡ and R. BOTTA* * Dipartimento di Colture Arboree, Università di Torino, Via Leonardo da Vinci 44, 10095 Grugliasco (TO), Italy, † USDA-ARS National Clonal Germplasm Repository, 33447 Peoria Rd., Corvallis, OR 97331 USA, ‡ Department of Horticulture, Oregon State University, 4017 Agricultural and Life Sciences Bldg., Corvallis, OR 97331 USA Abstract In this work, 18 microsatellite loci were developed in the European hazelnut ( Corylus avellana L.) using three enriched genomic libraries. They were evaluated on a set of 20 accessions of this species on the basis of number of alleles (mean: 7.1), expected heterozygosity (mean: 0.67), power of discrimination (mean: 0.77) and polymorphism information content (mean: 0.64). Cross-species transferability was evaluated using seven other Corylus species. All primer pairs amplified in all species, except for CaT-C505 in Corylus ferox and CaT-A114 in Corylus californica. Keywords: cross-species amplification, filbert, polymorphism, simple sequence repeats Received 05 May 2005; revision accepted 22 June 2005 Corylus species are widely distributed throughout temperate regions of the Northern Hemisphere from Japan, Korea, China and the Russian Far East to the Caucasus, Turkey, Europe and North America (Kasapligil 1972). The European hazelnut ( Corylus avellana L.) is a commer- cially important species. Cultivars in Europe and Turkey were selected, over many centuries, from local wild populations. In addition, several wild species have been crossed with the economically important C. avellana in an effort to obtain specific traits (Mehlenbacher 1991). Identification of hazelnut cultivars is primarily based on analysis of nuts, husks and other morphological traits. These, however, are often unre- liable or imprecise indicators of plant genotype, being influenced by environmental factors. Thus, discrimination among closely related cultivars and clones is often extremely difficult. Cultivar identification is especially difficult in a nursery setting where plants are young and not yet bearing. DNA typing can be a convenient method for accurately identifying hazelnut cultivars. Microsatellite or simple sequence repeat (SSR) molecular markers have been routinely isolated from plants and have been very useful because they are locus-specific, codominant, highly poly- morphic and highly reproducible. In this work, 18 microsatellite loci were developed in C. avellana and their polymorphism was studied in a set of 20 accessions of this species, coming from the various countries that grow hazelnut (Table 1). Their cross-species transferability was evaluated using representatives of seven other Corylus species (Table 1): C. colurna L., C. californica Marshall, C. ferox Wallich, C. heterophylla Fischer, C. papyracea Hickel, C. chinensis Franchet and C. americana Marshall. Furthermore, five individuals from the cross ‘Tonda Gen- tile delle Langhe’ × ‘Cosford’ (Romisondo et al . 1983) and the parent cultivars were analysed to check the segregation of alleles at each locus. Genetic Identification Services in Chatsworth, Cali- fornia, USA constructed three genomic libraries enriched for CA-, GA- and GAA-repeats, respectively, for Oregon State University (OSU), Corvallis, Oregon, USA, using DNA from dark-germinated seeds of a mixture of C. avellana cul- tivars and selections. Later, DNA was cloned into pUC19 vector and used to transform Escherichia coli DH5 α follow- ing the method of Edwards et al . (1996). DNA sequencing was performed with a BigDye Terminator Cycle Sequencing Ready Reaction kit version 2.0 using an ABI PRISM 377 sequencer (Applied Biosystems). All sequences obtained were blasted against each other using the bioedit version 5.0.9 package (http://www.mbio.ncsu.edu/BioEdit/bioedit.html) and duplicate sequences were removed. Primers were Correspondence: R. Botta, Fax: +39-011-6708658; E-mail: roberto.botta@unito.it