Genetic characterization of Genista sericea Wulfen (Cytiseae – Fabaceae) as revealed by nuclear DNA content and its nrDNA region analysis

Summary-Genista sericeaWulfen, a northern Illyrian amphi-Adriatic species, presents a certain morphological variability. To clarify whether the genetic variations support the morphological differences among accessions of different geographic origin, analysis of nuclear DNA content and polymorphism of the internal transcribed spacer (ITS) dataset was studied. The variation in nuclear DNA content ofG. sericeavar.sericeaand var.rigidais minimal (2.09 and 2.08 pg/nucleus respectively) and is correlated with equal chromosome numbers in both varieties. Intraspecific variability of the ITS region was studied on 13 accessions ofG. sericea, 6 belonging to var.sericeaand 7 to var.rigida. These accessions were analyzed in comparison to closely related species already studied. ITS sequences ofG. sericearevealed large polymorphism and formed two main clusters. One cluster (6 accessions) comprehends var.sericeaof northern Italy, Slovenia and northern Croatia; the other cluster (7 accessions) includes five accessions of var.rigidafrom southern Croatia and Montenegro and two from the Pollino massif (southern Italy). The later two accessions considerably differed from other accessions of var.rigida. This genetic analysis supports the previous assumptions, which subdividedG. sericeainto at least two taxa. On the basis of the results presented, it is here suggested that the subdivision ofG. sericeainto var.sericeaand var.rigidashould be maintained.