Genetic diversity of flax accessions originating in the Alpine region: a case study for an ex situ germplasm evaluation based on molecular marker

Agro-biodiversity is currently experiencing severe genetic erosion due to mankind’s unsustainable activities. Because of initiatives following the goal of the conservation of biological diversity, so far seven million crop accessions are being conserved ex situ in gene banks worldwide. Many of these accessions are landraces being rich in gene diversity, silently awaiting their proper characterisation. This is a very critical part of any long-term strategy to enhance the productivity and resilience of crops and agricultural systems and—most importantly—to ensure the preservation of our cultural and biological heritage. In this study of an ex situ germplasm evaluation we analysed 27 flax (Linum usitatissimum L.) accessions originating in the Alpine region, provided by five local gene banks/providers. Based on genomic microsatellite markers (gSSRs), a varying extent of accession-specific gene diversity (expected heterozygosity, H_E) was revealed ranging from 0.05 to 0.51. Admixture of individuals between accessions was uncovered, pointing towards past processes related to gene bank management activities (e.g. intentional selection, unintentional cross-pollination during regeneration) or towards the evolution of the landrace itself (e.g. same regional origin, traditional naming), highlighting the co-existence of cultural and biological diversity. Such an genetic analysis of accessions stored ex situ not only produces valuable agronomic and breeding data, but also is useful for the clarification of past processes leading to duplicates within and between collections or mislabelling, contributing to the potential for rationalisation of collections, which in turn can help ensure that the limited resources available for regeneration are used most efficiently and effectively.