Phylogenetic studies of Elymus s.s. L. (Poaceae) : plant systematics as a prerequisite for efficient conservation and utilization

Elymus (wild-rye), in the tribe Triticeae, is a diverse genus and contains about 150 species growing in a wide range of habitats in temperate areas all over the world. The species are wild relatives to some of the most important cereal crops like bread wheat, durum wheat, rye, and barley. The genus is considered a genetic resource and contains many valuable traits that could be used in future crop breeding for sustainable agriculture. Several species are used today as forage grasses and others could potentially be introduced as new crops. To fully explore, exploit and conserve the genetic diversity of Elymus, basic knowledge of the systematics of the genus is needed. This thesis focus on Elymus s.s., including only species with an StH genome combination, and investigates the phylogeny and phylogeography on different taxonomical levels: within a species (Paper I), within a region (Paper II) and within a genus (Paper III). Genotyping-By-Sequencing techniques were used to explore the relationships, diversification, generic structure, migration, and origin of the genus. The results indicate separate origins of American and Eurasian species and show a complex relationship between Elymus in South and North America with multiple migration events. The thesis gives insights into the evolutionary history of Elymus s.s. and provides phylogenetic data for further taxonomical work within the genus