Genetic variability and genomic divergence of Elymus and related species

In order to study the genetic variation and phylogenetic relationship in Elymus repens, amplified fragment length polymorphism (AFLP) were used, together with sequence data for the nuclear gene phytochrome B, phyB, and the chloroplast ribosomal protein encoding gene rps4. A total of 83 collected E. repens samples, 3 E. repens reference samples and 18 related species accessions were analysed and compared with 13 GenBank sequences. AMOVA analysis revealed a moderate genetic differentiation between the populations of E. repens in the three Swedish provinces investigated, while no differentiation was observed due to landscape type. A moderate genetic differentiation was also found when samples from different fields in one province were compared to samples from a selected field. A common female origin was found in E. repens and seven other Elymus species, Pseudoroegneria spicata, Thinopyrum intermedium, T. junceum, Hordeum bogdanii and H. stenostachys. The latter two both harbour the H genome. Taken together, the data suggest that the Swedish E. repens population is slightly heterogeneous and comprises multiple origins of genome donors; a nuclear genome with contributions from Pseudoroegneria (St), Hordeum (H), Thinopyrum (E) and Y with an unknown donor together with a maternal genome donated from Pseudoroegneria.