Mean number of chromocentres in the interphase nuclei has been studied in two inbred lines of radish(Raphanus sativusL. var.radicolaPersoon), their F1hybrid and the original population. The inbred lines showed a significantly higher mean of chromocentres in the interphase nuclei than the original population, suggesting more heterochromatinization in the former. Mean number of chromocentres in the nuclei is restored in the plants of F1interlinear hybrid. A genotypic control of chromocentres has been proposed in radish.