Genetic Maps of Miscanthus sacchariflorus Robustus and M. sinensis using EST-derived SSRs, and Their Preliminary Comparison to Sorghum

Genetic maps from a cross between Miscanthus sacchariflorus Robustus and M. sinensis were constructed. Sugarcane-EST-derived SSRs were mapped by the two-way pseudo-testcross model due to the high heterozygosity of each parental species. A total of 261 loci were mapped in M. sacchariflorus, spanning 40 linkage groups and 1,998.8 cM, covering an estimated 72.7 % of the genome. For M. sinensis, a total of 303 loci were mapped, forming 23 linkage groups and 2,238.3cM, covering 84.9 % of the genome. The use of EST-derived SSR loci permitted alignment of the Miscanthus linkage groups to the sorghum chromosomes, revealing a whole genome duplication event affecting the Miscanthus lineage after the divergence of subtribes Sorghinae and Saccharinae, as well as traces of the pan-cereal whole genome duplication. It remains a question whether the whole genome duplication found in Miscanthus is shared by Saccharum species. While the present maps provide for many research needs in this emerging crop, additional markers are also needed to improve map density and to further characterize the structural changes of the Miscanthus genome since its divergence from sorghum and Saccharum.