Morphological and molecular characters: Congruence or conflict in the phylogeny of Sulla species?

Sulla genus (Hedysarea) includes six Mediterranean species constituting an important phytogenetic patrimony primarily used to promote feed production chiefly in arid and semi arid regions. In order to perform a phylogenetic analysis of Sulla species, both morphological and molecular data were used. The morphological data was comprised of 10 characters, while the molecular characters were comprised of 52 phylogenetically informative sites from ITS ribosomal DNA and 85 informative ISSR markers and 295 AFLP markers. Phylogenetic reconstruction was performed by an analysis of separate and combined molecular and morphological data. Three separate topologies’ baselines were evaluated. Three species, from a Hedysarum genus, were used as outgroup to validate the findings and the monophyly of Sulla species. The combined analysis showed a genetic convergence between the southern S. spinosissima and the northern S. coronaria. Moreover, the ability to differentiate species by these various techniques was confirmed by Pearson correlation coefficients. This test established the incongruence between morphological and molecular markers revealed in Sulla genus. In summary, the findings show a recent evolution of the Mediterranean Sulla species and confirm that the analysed species are descended from a common ancestor. The main goal of this study is to provide a robust tool for showing the phylogeny of Sulla species utilizing distinct characteristics.