PCA analyses were carried out using the similarity matrices generated with both the AFLP and the SSR markers. The first two components of the PCA analysis using the AFLP data explained 20.4 and 14.3% of the total variation (Fig. 1a). Three major clusters were observed. One cluster contained the Saccharum species and another all of the Erianthus species apart from E. fulvus and E. rockii. The third cluster was located between the other two clusters and contained E. rockii, E. fulvus, the two Miscanthus species and N. porphyrocoma, as well as P. schumach. The third PCA component explained 8.5% of the variation and further separated the genera in cluster 3 above (Fig. 1b). In this component, the four E. rockii accessions clustered with three of the five Miscanthus accessions, and not with E. fulvus or N. porphyrocoma. The PCA performed with the SSR data gave similar results although the clustering was less tight (Fig. 1c and d). Components 1 and 2 explained 13.6 and 4.9% of the variation, respectively. In this analysis, four loose clusters were observed, namely Erianthus spp. (excluding E. fulvus and E. rockii), Miscanthus spp. and Narenga sp., E. rockii and E. fulvus, and Saccharum spp., with E. rockii positioned between the Miscanthus/Narenga cluster and the Saccharum spp. cluster (Fig. 1c). The third PCA component explained 3.3% of the variation and separated the Saccharum spp.