RegioDiv – Genetic diversity patterns of herbaceous plants in Germany and practical implications for seed zone management

Walter Durka, Helmholtz Centre for Environmental Research (Halle, Germany)

A generalized system of 22 “regions of origin”, i.e. seed zones, is in action since 2010 for the production and use of regional grassland seeds in Germany. The system has been questioned because it is based solely on ecoregions, lacks a foundation in genomics and adaptation, and potentially uneconomic zone size.  The RegioDiv project analysed genetic diversity of more than 30 plant species (12,000 samples) using SNP markers in all seed zones to test how well seed zones represent genetic patterns. Important exemplary results and recommendations are presented. Each species showed a species specific pattern of genetic variation but nearly all species showed an isolation-by-distance pattern of increasing genetic distance with increasing geographic distance. For some species with multiple ploidy levels, which can represent separate biological species, species-specific management rules were developed based on cytotype distribution. The synthesis of the distribution patterns of intraspecific genetic groups identified mismatches with current seed zones. Alternative seed zones that better integrate genetic patterns across all species are presented. They are the basis for potential changes to the seed zone system which have to be developed together with relevant stake holders in the near future. The results of the RegioDiv project will be discussed with respect to the seed zone systems of Austria.