Molecular characterization of the autochthonous grape cultivars of the region Friuli Venezia Giulia – North-Eastern Italy

Abstract

A sample of 48 accessions belonging to important autochthonous grapevine varieties from Friuli Venezia Giulia (North-Eastern Italy) was analyzed using two sets of microsatellite markers. One marker set, based on di-nucleotide core repeats, was compared with a recently developed set of markers based on tri-, tetra-, and penta-nucleotide repeats in order to determine genetic identities, estimate genetic diversity, and establish the power of discrimination of the two sets. A total of 20 di-nucleotide SSR markers and 19 tri-, tetra-, and penta-nucleotide SSR markers were used to screen the accessions.
All 39 primers produced PCR amplicons that were polymorphic and easily scorable in all of the accessions studied. Both datasets allowed the discrimination of all cultivars but two ('Refosco di Runcis' and 'Refoscone'). The observed heterozygosity ranged from 0.21 to 1.0 for the di-nucleotide markers, and from 0.21 to 0.88 for the tri-, tetra-, and penta-nucleotide repeat motif microsatellites, respectively.
The population structure of the 48 autochthonous accessions was evaluated, together with 8 international cultivars included as references, providing evidence for significant population structure within the sample. Microsatellites composed of tri-, tetra-, and penta-nucleotide repeats, characterized by low ‘stuttering’ and larger relative size differences between incremental alleles, are now available for grape fingerprinting.