Usefulness of microsatellites for positioning the tunisian almond germplasm in its mediterranean geographic context.

Abstract

6 Pags.- 1 Tabl.- 1 Fig. The definitive version is available at: http://www.actahort.org/index.htmIn Tunisia, the almond tree (Prunus dulcis), dating back to ancient times, has been grown extensively since the Carthaginian era. In the framework of a national project on the characterisation and the conservation of the local almond germplasm many morphological and molecular markers (RAPD and SSR) have been used in order to analyse the genetic diversity of the main almond cultivars and to seek for the genetic position of these resources in the Mediterranean basin. For this study, 10 SSRs were used to analyse 82 almond accessions from different origins. Most of them originated from Tunisia (50), the others included in the National collection were from France (9), Italy (7), Morocco (1), Spain (8), USA (3), or were of unknown origin (4). The dendrogram based on UPGMA analysis using the similarity matrix generated by the Nei and Li (1979) coefficient presented four main clusters (A, B, C and D). In group A were present 40 of the 50 local genotypes that originate from the centre and the south contrarily, all cultivars from the north were in group C and clustered with the European and American genotypes. Accordingly, our study stressed the large diversity of the Tunisian almonds and revealed the presence of two distinct genetic groups. One located in the north genetically close to the gene pool of the Northern border of the Mediterranean and the second in the central and southern part that is highly adapted to different abiotic stress mainly drought.Peer reviewe