Karyological Studies and FISH Landmarks on Somatic Chromosomes of Saccharum officinarum and S. spontaneum

Detailed karyotypes of Saccharum officinarum and Saccharum spontaneum were constructed on the basis of chromosome length and arm ratio. The results of karyotypic analysis revealed that the longest chromosome of the complement was about triple in length of the shortest chromosome in S. spontaneum and double in S. officinarum. The chromosome size varied from 1.66 μm to 5.13 μm with predominance of metacentric chromosome. 18S-5.6S-25S and 5S rDNA sites were located by in situ hybridization to the Saccharum genus. For each species and each rDNA family, the position and number of sites in the various cytotypes suggested the presence of one locus and basic chromosome numbers of ten for S. officinarum and eight for S. spontaneum.