Molecular cytogenetics of Bellevalia (Hyacinthaceae) species occurring in Greece

Eight taxa of the genus Bellevalia (Hyacinthaceae) occurring in Greece, all with basic chromosome number x = 4, were cytologically studied using classical and molecular-cytogenetic techniques [fluorochrome banding with chromomycin A(3), fluorescence in situ hybridization (FISH) using probes of 18S-5.8S-26S and 5S ribosomal RNA genes]. Two of the examined taxa are endemic, i.e., B. brevipedicellata and B. sitiaca, both restricted to the Island of Kriti. B. hyacinthoides and B. edirnensis are Balkan endemics, and the four remaining taxa, i.e., B. dubia subsp. boissieri, B. trifoliata, B. romana, and B. ciliata, are more widely distributed Mediterranean elements. Genome size, estimated by flow cytometry, ranged from 18.59 to 53.38 pg. The results of fluorochrome banding and FISH are reported for the first time for the genus Bellevalia. Despite the morphological similarity of the chromosome complement, which is in accordance with the general "basic" Bellevalia karyotype formula, the karyotypes of the studied species are clearly distinguished by the number and position of GC-rich bands and ribosomal DNA (rDNA) loci, revealing clear interspecific differentiation among the taxa. Additionally, examination of the polyploid species B. sitiaca and B. edirnensis and populations of B. hyacinthoides and B. ciliata with different ploidy levels permits discussion about the origin of polyploids and the taxonomic relationships among the taxa.