II. 29. Mutagenic effects of gamma-rays, EMS, and HA in barley.
R.M. Singh, J. Singh and A. N. Srivastava, Dept. of Genetics and Plant Breeding, Faculty of Agriculture, Banaras Hindu University, Varanasi--221005, India.
Influence of three mutagens, i.e., gamma-rays, EMS, HA, separately and in combination, on radiobiological response, mutation frequency, and mutation spectrum was investigated in five cultivars, i.e., K-24, IB-226, K 527/11, DL-3, and Amber of barley, Hordeum vulgare. Treatments with EMS and HA followed gamma irradiation after 16 hours of presoaking of irradiated as well as control seeds in distilled water.
In general, combined treatments resulted in additive effects, but in cultivars K 572/11 and K-24, synergistic and protective actions were noted respectively for germination. Field survival was lowest in Amber and highest in DL-3. Differential response to mutagens occurred of various cultivars. Combination treatments showed additive effect in K-24 and DL-3 and protective effect in IB-226, K 572/11 and Amber. Seedling height reduction at 12th day was minimum in IB-226 and maximum in Amber. Gamma rays per se were more effective than either EMS or HA. Combination treatments gave synergistic effect in K-24 and DL-3. Gamma-rays produced significant reduction in pollen fertility of a number of cultivars, whereas chemical mutagens had little effect in most of the varieties.
In all the cultivars EMS was more effective in inducing chlorophyll mutations than either gamma-rays or HA. Combination treatments often were more effective than individual treatments in all the cultivars. Maximum number of chlorophyll mutations were recovered in cultivar DL-3 and lowest in IB-226. Virescence, striata, tigrina, and maculata occurred in lower frequency than Albina, Xantha, and dark Xantha. All the three mutagens separately, were quite inefficient in producing dark Xantha, but in combination treatments its frequency increased several-fold. Viable mutation frequency over treatments for different cultivars were almost similar. However, various treatments showed significant differences in inducing viable mutations. HA was least effective and combination treatment of gamma-ray with EMS was most effective. In general, combination treatments showed somewhat protective effects rather than additive or synergistic action. Combination of EMS with gamma-rays gave the widest mutation spectrum. In separate treatments HA was least effective and gammarays most effective. Some degree of mutagenic specificity occurred, as multiawned mutants were observed only in gamma-rays and red awned mutants only in HA and combination treatment of gamma-rays + HA.