Flow cytometric and cytogenetic analyses of Iberian Peninsula Festuca spp.

Abstract

Festuca L. has an important diversification centre in the Iberian Peninsula. We used chromosome counting, fluorescence (FISH) and genomic in situ hybridization (GISH), and DNA flow cytometry (FCM) to clarify the taxonomic position of several taxa, to search for phylogenetic relationships and to assess the extent and pattern of genome variation in fescues. The chromosome number of Festuca duriotagana var. barbata is determined for the first time and new ploidy level estimations are given for F. rothmaleri and F. summilusitana. In the latter species, besides the reported decaploid level, dodecaploidy was found in some populations, which points to the existence of an unrecognized taxon. Moreover, these differences were confirmed by FCM and a high positive correlation was found with the type of substrate where F. summilusitana was growing. For each section, a decrease of genome size with increase of polyploidy was observed. In general, in situ hybridization techniques failed to reveal phylogenetic relationships among the selected species. In FISH, a variation in the number of rDNA sites was observed in some species. GISH results indicate that F. henriquesii is not a progenitor of the studied polyploid species.