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

Seed collection and storage of wild species in ex-situ seed banks should be continued as an integrated toolfor the conservation of plants in their habitats. Although seed-bank facilities are widely used today, theirseed samples often suffer low genetic diversity. Consequently, reintroduced seeds and plant materialmay not have the resilience to cope with future environmental stress so leading to complete wastage ofseeds. Molecular techniques allow the benefit of quantification of the genetic diversity of a seed collectionin comparison with that of the natural population. In this study we focus on ex-situ seed bank samplesand living collections of Ranunculus peltatus subsp. baudotii. We compare their genetic diversity andstructure with that of the natural population before and after undertaking a restoration project on anatural pond in the Tuscan Archipelago National Park. ISSR analyses, carried out on a total of five samplinggroups, shows a relatively high level of genetic diversity for the ex-situ cultivated groups. The analysisof molecular variance, in agreement with clustering obtained in the neighbour-joining dendrogram andwith the pattern from cluster analysis, suggests dividing the samples analysed into two groups: oneformed by individuals sampled before the pond restoration and the other formed by the subsequentpond population. The results highlight the importance of planning mixed propagation lines which canbe obtained through the use of a range of germination conditions to exploit a novel source of geneticvariability which may otherwise remain hidden within the seed collection.