Barley seeds were irradiated with varying doses of thermal neutrons before treating them with diethyl sulphate (dES). In combined treatments of thermal neutrons and dES, the seedling height data indicated slight synergistic effect at lower doses and protective effect at higher doses. In contrast, combined treatments of gamma rays and dES resulted in synergistic effect on seedling height at all the doses used. The frequency of anaphase fragments and bridges was less in seeds stored after neutron irradiation than in those hydrated immediately after irradiation. Diethyl sulphate treatment when given immediately after thermal neutron irradiation did not enhance chromosome aberrations; but with post irradiation storage, dES treatment increased the frequency of both anaphase fragments a bridges.
