Annals of Applied Biology ISSN 0003-4746 RESEARCH ARTICLE Genetic characterisation of traditional chestnut varieties in Italy using microsatellites (simple sequence repeats) markers M.A. Mart´ ın, C. Mattioni, M. Cherubini, D. Taurchini & F. Villani Istituto di Biologia Agroambientale e Forestale (IBAF), Consiglio Nazionale delle Ricerche (CNR), Viale Marconi 2, 05010 Porano (TR), Italy Keywords Chestnut; genetic diversity; homonymies; SSR markers; synonymies; traditional varieties. Correspondence M.A. Mart´ ın, Istituto di Biologia Agroambientale e Forestale (IBAF), Consiglio Nazionale delle Ricerche (CNR), Viale Marconi 2, 05010 Porano (TR), Italy. Email: ge2macum@uco.es Received: 1 April 2009; revised version accepted: 1 February 2010. doi:10.1111/j.1744-7348.2010.00407.x Abstract European chestnut (Castanea sativa) is an important multipurpose tree that has been cultivated for wood and fruit in the Mediterranean basin since ancient times. Cultivation of traditional chestnut varieties has a long tradition in Italy, where cultivars have been selected over centuries as a function of the best nut traits. In this study, 94 grafted chestnuts corresponding to 26 representative cultivars from Italy were evaluated by seven simple sequence repeat (SSR) markers to establish whether they corresponded to varieties in the narrow sense. The results allowed 20 genotypes to be identified that corresponded to the same number of clones. In total, 52 alleles were identified, eight of which were exclusive. Cases of homonymies and synonymies were detected. Moreover, our results highlighted a considerable genetic uniformity among ‘Marrone-type’ cultivars and, on the contrary, a high genetic diversity among the evaluated cultivars demonstrating that this is a valuable germplasm and an important genetic resource to be preserved. Introduction European chestnut (Castanea sativa Mill.) is one of the most economically important multipurpose tree species of the Mediterranean region. It is cultivated both for fruit and timber and is important not only for its socioeconomic and cultural value but also for its contribution to the landscape and environment. Over many centuries, humans have influenced C. sativa populations through propagation and transplanting of plant material, intensive cultivation of grafted (clonal) plants, silvicultural practices and fragmentation of populations because of changes in land use (Columela, 1979; Pitte, 1986; Adua, 1999; Conedera et al., 2004). For a long time, chestnut was one of the main cultivated food sources for rural populations in mountain regions (Bourgeous, 1992); however, in the last five decades, fruit production has decreased because of human depopulation of mountain areas and the replacement of the species by other crops. These factors, coupled with massive pathogen attacks (Cryphonectria parasitica and Phytophthora spp.) over long periods, have reduced the areas devoted to fruit production and impoverished extant genetic stocks in many European countries (Bruneton, 1984; Arnaud et al., 1997). Recently, with the changes in food habits of consumers, chestnut has gone from a fruit of everyday use to a product with multiple quality requirements (Bounous, 2002). There is renewed interest in traditional chestnut varieties because of the increasing market for traditional products with a high value and superior quality as attributed by the consumers (Negri, 2003). This is the case of the chestnut ‘Marrone-type’, defined as chestnut without signs of episperm intrusion in the kernel or with a low division percentage (<12%; Bergougnoux et al., 1978). In Italy, ‘Marrone-type’ means a particular C. sativa cultivar of excellent nut quality (large sized, oblong shape, reddish epicarp, raised stripes and small semi-rectangular hilar). Italy has a long tradition in cultivation of tradi- tional chestnut varieties that have been selected over centuries for the best nut traits. It is the princi- pal producer of chestnut fruit in Europe with 55,000 tonnes annually (FAOSTAT, 2007, Agricultural data, http://faostat.fao.org/faostat/); the principal regions of production are Campania, Calabria, Lazio, Piemonte and Toscana. Ann Appl Biol 157 (2010) 37 – 44 © 2010 The Authors 37 Journal compilation © 2010 Association of Applied Biologists