Results
Numbers of 5S and 25S rDNA sites visualized by fluorescence
in situ hybridization in one or more accessions
of each studied taxon are shown (Table 1). For each
accession, at least five cells with good chromosome
spreads and hybridization signals were observed. In all
the species including the diploids and polyploids, 5S
rDNA sites were all localized on proximal regions of
short chromosome arms, and 25S rDNA sites were all
localized on terminal chromosomal regions. The site
numbers of both rDNA types was consistent within
each level of ploidy, with the following exceptions. As
detailed below, five diploid cytotypes had less than the
number of 25S signals presented by the typical diploid
cytotype. The intensity and size pattern of 25S signals
displayed variability within the diploids. Also, a difference
of 25S site number was observed between the two
hexaploid F. moschata (CFRA 157 and CFRA 376) genotypes.
Finally, the two decaploid taxa differed from each
other in both 5S and 25S site numbers.