Genetic diversity and hybridization of Japanese Miscanthus sinensis and Miscanthus sacchariflorus

Miscanthus is a genus of perennial grasses native to east Asia and is emerging as an important crop for the lignocellulosic bioenergy industry. To enable breeding of improved biomass cultivars, we used restriction site-associated DNA sequencing (RAD-seq) to characterize the genetic diversity of diploid M. sinensis and tetraploid M. sacchariflorus native to Japan. In addition to identifying triploid and tetraploid hybrids between these two species, we detected a large amount of introgression from M. sinensis to M. sacchariflorus, such that very few individuals could be considered pure M. sacchariflorus. Knowledge of this introgression will be important when choosing parent individuals to use in the creation of new M. xgiganteus (M. sacchariflorus x M. sinensis) hybrid cultivars. We also found rare M. sinensis individuals with introgressed DNA from M. sacchariflorus, primarily in northern Japan. Lastly, we examined the spatial genetic structure of M. sinensis across Japan, which will guide germplasm collection efforts.