Genetic variation in Italian wild cherry (Prunus avium L.) as characterised by nSSR markers

The main aim of our research was to describe the level and distribution of genetic variability of wild cherry (Prunus avium L.) in Italy, using eight nuclear microsatellite markers. The sampled plants were grouped in 11 internally homogeneous breeding zones, defined according to their ecological and vegetational conditions. The mean observed heterozygosity (Ho) was 0.573, and the expected (He) 0.698. Significant departures from Hardy–Weinberg equilibrium at each locus were found for all breeding zones (P,0.01). The mean fixation index, calculated taking into account the estimated null allele frequencies, was 0.075, showing a slight excess of homozygotes. FST (departure of genotype frequencies within populations from Hardy–Weinberg expectations, commonly used as an estimator of genetic differentiation among populations) showed a mean value of 0.046, indicating a slight, although significant, differentiation among breeding zones. However, in general, it was not possible to observe a structuring linked to the geographical location of the breeding zones. The results of the study contribute to a better understanding of our knowledge of the wild cherry genetic variation in Italy, thus making for more efficient programmes aimed at the preservation of biodiversity and for more rational planning of the management of reproductive material. Since our results do not show a clear structuring of genetic variability within the Italian diffusion area of wild cherry, it is not possible to draw any indications on regions of provenance delimitation based only on genetic data, and the identification of the latter should be based mainly on ecological and vegetational features.