The karyomorphological studies of the ten different strains of R. sativus show homogeneity in their gross morphology. However, minute structural difference between different strains are noticed in relation to the number of secondary constriction, the position of the primary constrictions as well as in the arm ratio. However, in one of the strains, viz. “Deshi red long” the chromosome size has been found to be comparatively longer than the rest as noted from the histogram as well. It is likely that this strain is the representative of the primitive stage and that other strains with shorter chromosomes are evolved through horticultural practices. In that case the diminution in chromosome size is assumed to have taken place during evolution. It has been suggested that the structural changes in chromosome have played an important role in the evolution of different taxonomic units of Raphanus sativus L.