BIOLOGIA PLANTARUM 53 (1): 164-166, 2009 164 BRIEF COMMUNICATION Development and evaluation of microsatellite markers in Phoenix dactylifera L. and their transferability to other Phoenix species A. AKKAK 1 *, V. SCARIOT 2 , D. TORELLO MARINONI 3 , P. BOCCACCI 3 , C. BELTRAMO 3 and R. BOTTA 3 Dipartimento Scienze Agro-Ambientali, Chimica e Difesa Vegetale, Università degli Studi di Foggia, Via Napoli 25, I-71100 Foggia, Italy 1 Dipartimento di Agronomia, Selvicoltura e Gestione del Territorio 2 , and Dipartimento di Colture Arboree 3 , Università di Torino, Via Leonardo da Vinci 44, I-10095 Grugliasco, Italy Abstract Forty one simple sequence repeats were isolated from two microsatellite enriched libraries of date palm (Phoenix dactylifera L.). After screening, 17 selected microsatellite loci were characterized and evaluated on a set of 31 cultivars and clones from Algerian and Californian germplasm. All primer pairs produced an amplification product of the expected size and detected high polymorphism among the analysed samples. These nuclear simple sequence repeat (SSR) markers are expected to be a very effective tool for evaluating genetic diversity in date palm germplasm. Across- taxa amplification showed the usefulness of most SSR markers in 14 other species across the genus Phoenix. Additional key words: across-taxa transferability, date palm, simple sequence repeats. ⎯⎯⎯⎯ Date palm (Phoenix dactylifera L.) is a long-lived dioecious monocotyledonous fruit plant (2n=36) belonging to the Arecaceae family (Barrow 1998). It is believed to have originated in Mesopotamia and thousands of cultivars have been reported (Hanachi et al. 1998). Date palms have always been clonally propagated to ensure the identity and uniformity of the cultivars. However, the existence of intra-cultivar variation could potentially cause confusion in cultivar nomenclature, preservation and utilization (Devanand and Chao 2003). Discrimination among closely related cultivars and clones is often extremely difficult. Identification of date palm cultivars is principally based on fruit morphology (Elhoumaizi et al. 2002). However, morphological traits are often unreliable or imprecise indicators of plant genotype, being influenced by environmental conditions or varying with the developmental stage of plants. DNA typing can be a convenient method for accurately identi- fying date palm cultivars and analysing their genetic diversity and phylogenic relationships. Microsatellite or simple sequence repeat (SSR) molecular markers have been proven to be very powerful in plant diversity analysis because they are locus-specific, codominant, highly polymorphic and highly reproducible. Recently, microsatellite markers have been developed and used to investigate genetic diversity in P. dactylifera (Billotte et al. 2004). However, for a wider use of this technology, the enlargement of the number of markers suitable for evaluating DNA polymorphisms in this crop is necessary. In this study, we report the development of 17 new SSR markers for P. dactylifera. Their polymorphism was studied in a set of 31 cultivars and clones of this species. Their cross-species transferability was evaluated on 14 other Phoenix species. Such investigation would be of great interest in breeding programs (Ould Mohamed Salem et al. 2007). Leaf samples of P. dactylifera were collected from 31 cultivars and clones from three Algerian oasis (Adrar, Biskra, Golea) and from the USDA-ARS National Germplasm Repository (California). Total genomic DNA ⎯⎯⎯⎯ Received 17 November 2007, accepted 6 December 2008. Abbreviation: SSRs - simple sequence repeats. Acknowledgements: This research was supported in part by the Comune di Sanremo. We thank the USDA-ARS National Germplasm Repository (California), the CIRAD (France), the Royal Botanic Gardens, Kew (United Kingdom), and the Algerian Research Center for providing samples and collaboration. * Author for correspondence; fax: (+39) 0881 589342, e-mail: a.akkak@unifg.it