The karyotype of Festucopsis serpentini (Poaceae Triticeae) from Albania studied by banding techniques and in situ hybridization

The karyotypes of two populations of Festucopsis serpentini (2n = 2x = 14) endemic to Albania were investigated in detail by Giemsa C- and N-banding, AgNO3 staining, and in situ hybridization with an rDNA probe. The complements consisted of 14 large chromosomes, 10 metacentric and 4 SAT-chromosomes, a metacentric and a submetacentric pair. SAT-chromosomes from one population carried exclusively minute satellites, whereas SAT-chromosomes from another population also carried larger polymorphic satellites, suggesting a geographical differentiation. The existence of four chromosomes with nucleolus forming activity was established through AgNO3 staining; however, the rDNA probe additionally hybridized to intercalary positions in the short arms of two metacentric chromosomes revealing two inactive rDNA sites. C-banding patterns comprised from zero and up to four very small to larger, generally telomeric bands per chromosome giving low levels of constitutive heterochromatin. Similarities in chromosome morphology and C-banding patterns identified the homologous relationships of all chromosomes in one population, but of three pairs only in the other. Reliable identification of homologous chromosomes between plants was only possible for the SAT-chromosomes. A comparison between the C-banded karyotypes of F. serpentini and Peridictyon sanctum supports their position in two genera.