Analysis of genetic structure of Ranunculus baudotii in a Mediterranean wetland. Implications for selection of seeds and seedlings for conservation

•We focused on genetic structure of Ranunculus baudotii from an isolated Mediterranean wetland.•Genetic structure from the ex-situ seed-bank and living collection was also examined.•A relatively high level of genetic diversity for the ex-situ groups was observed.•The analysed sampling groups should be grouped into two separate conservation units.•We plan mixed propagation lines in order to obtain a new source of variability. Seed collection and storage of wild species in ex-situ seed banks should be continued as an integrated tool for the conservation of plants in their habitats. Although seed-bank facilities are widely used today, their seed samples often suffer low genetic diversity. Consequently, reintroduced seeds and plant material may not have the resilience to cope with future environmental stress so leading to complete wastage of seeds. Molecular techniques allow the benefit of quantification of the genetic diversity of a seed collection in comparison with that of the natural population. In this study we focus on ex-situ seed bank samples and living collections of Ranunculus peltatus subsp. baudotii. We compare their genetic diversity and structure with that of the natural population before and after undertaking a restoration project on a natural pond in the Tuscan Archipelago National Park. ISSR analyses, carried out on a total of five sampling groups, shows a relatively high level of genetic diversity for the ex-situ cultivated groups. The analysis of molecular variance, in agreement with clustering obtained in the neighbour-joining dendrogram and with the pattern from cluster analysis, suggests dividing the samples analysed into two groups: one formed by individuals sampled before the pond restoration and the other formed by the subsequent pond population. The results highlight the importance of planning mixed propagation lines which can be obtained through the use of a range of germination conditions to exploit a novel source of genetic variability which may otherwise remain hidden within the seed collection.