The genetic diversity and structure of the Ferula communis L. complex (Apiaceae) in the Tyrrhenian area

The giant fennel Ferula communis L. is a circum-Mediterranean complex characterized by a great morphological variability, and comprising several species and subspecies. In this work, we used AFLP markers to investigate the pattern of genetic variation of the F. communis complex in the Tyrrhenian area and to compare the levels of genetic diversity between the widespread F. communis and the Corso-Sardinian endemic congener F. arrigonii.Our study indicates fairly high levels of genetic diversity for all populations (Fragpoly = 58.2-88%; Hj = 0.186-0.313), with no significant differences between F. arrigonii and F. communis. The genetic structure is only partially coherent with the geographic provenance of the populations: while individuals of F. arrigonii constituted a separate genetic group, the individuals of F. communis were partitioned into three main genetic clusters. These corresponded respectively to F. communis subsp. glauca, to populations from Tunisia and Gozo Island, and to all populations from the rest of the investigated areas; this last cluster was characterized by a marked substructure.