Genetic diversity in the Centaurea cineraria group (Compositae) in Sicily using isozymes

The genetic diversity of seven taxa endemic to Sicily, C. cineraria, C. busambarensis, C. ucriae subsp. ucriae, C. ucriae subsp. umbrosa, C. todari, C. erycina and C. saccensis, from 11 localities was investigated using isozymes. Eight loci from five enzyme systems (IDH, MDH, PGD, PGM and PGI) were examined. A total of 19 alleles were identified, some rare and two of them exclusive to different populations. The allelic frequencies and the genetic variability values for each population were calculated. On the whole, the genetic diversity, i.e., average polymorphism (P)=0.41, average number of alleles per locus (A)=1.75, Nei’s gene diversity (H)=0.18, is moderate, with the highest genetic variability found in the populations of C. todari. The dendrogram shows two major groups: the first consists of all Sicilian populations except those of C. todari; thesecond of C. cineraria from the region of Campania and C. todari.