Chromosome complex of the relict diploid species Hieracium bracteolatum

In the predominantly polyploid and apomictic genus Hieracium (Asteraceae) sexual diploids are extremely rare and their distribution is limited mainly to the refugial areas of southern Europe. Here we characterized for the first time the chromosome complex of the relict species Hieracium bracteolatum from a diploid population on the Greek Island of Evia. The cytogenetic analysis based on classical chromosome staining, C-banding/DAPI method and fluorescence in situ hybridization with rDNA probes (rDNA-FISH) showed no major differences in the karyotype structure between this relict species and other diploids within the genus, especially in terms of chromosome morphology and rDNA location. Our study is part of the still very scarce research on the karyotype organization in sexual Hieracium taxa.