Chromosome Karyotyping of Senna covesii and S. floribunda based on Triple‑color FISH Mapping of rDNAs and Telomeric Repeats

The genus Senna in the family Fabaceae is distributed and cultivated around the world and has been used as sources of medicine and commercial goods. Molecular cytogenetic study based on FISH technique is useful for breeding and genomic research of the species. Triple-color FISH karyotype analyses were carried out to understand the genome structure of two Senna species, S. covesii (A. Gray) H. S. Irwin & Barneby and S. floribunda (Cav.) H. S. Irwin & Barneby using 5S rDNA, 45S rDNA, and telomeric repeat probes. Three and one pairs of 45S and 5S rDNA signals were detected, respectively, in S. covesii, whereas one pair each of 45S and 5S rDNA signals, were detected in S. floribunda. Telomeric signals appeared at all chromosome termini in both species. This result provides basic cytogenetic information which will be useful for future breeding and genomic research of Senna species.