Miscanthus: inter- and intraspecific genome size variation among M. xgiganteus, M. sinensis, M. sacchariflorus accessions

Since M. sinensis Anderss., M. sacchariflorus (Maxim.) Hack. and M. ×giganteus J.M.Greef & Deuter ex Hodk. and Renvoize have considerably the highest potential for biomass production among Miscanthus Anderss. species, there is an urgent need to broaden the knowledge about cytological characteristics required for their improvement. In this study our objectives were to assess the genome size variation among eighteen Miscanthus accessions, as well as estimation of the monoploid genome size (2C and Cx) of the M. sinensis cultivars, which have not been analyzed yet. The characterization of three Miscanthus species was performed with the use of flow cytometry and analysis of the stomatal length. The triploid (2n = 3x = 57) M. sinensis 'Goliath' and M. ×giganteus clones possessed the highest 2C DNA content (8.34 pg and 7.43 pg, respectively). The intermediate 2C-values were found in the nuclei of the diploid (2n = 2x = 38) M. sinensis accessions (5.52–5.72 pg), whereas they were the lowest in the diploid (2n = 2x = 38) M. sacchariflorus ecotypes (4.58–4.59 pg). The presented study revealed interspecific variation of nuclear DNA content (P<0.01) and therefore allowed for recognition of particular taxa, inter- and intraspecific hybrids and prediction of potential parental components. Moreover, intraspecific genome size variation (P<0.01) was observed in M. sinensis cultivars at 3.62%. The values of the stomatal size obtained for the triploid M. ×giganteus 'Great Britain' (mean 30.70 μm) or 'Canada' (mean 29.67 μm) and diploid M. sinensis 'Graziella' (mean 29.96 μm) did not differ significantly, therefore this parameter is not recommended for ploidy estimation.