“…Since the length of the chromosomes is liable to be affected, at least in part by the degree of condensation as well as the pressure exerted on the glass slide used in microscopy, while making the squash preparations, it was not apparent as to whether these differences in the total length of the chromosome complements truely reflect the differences in the amount of chromatin material. Moreover, the karyotypic details further indicated the subgenera as natural groups, since most of the species and varieties under any subgenus showed a clustering of the karyological parameters (JOHN 1989).…”