Enrichment of Pisum sativum gene resources through combined use of physical and chemical mutagens

The potential of induced mutations is of importance in genetic improvement of crops. In the experiments different physical and chemical mutagens were used (gamma-rays, fast neutrons, ethyl methanesulfonate (EMS), ethylene imine (EI), diethyl sulfate (DES), and nitroso methyl urethane (NMU)) applied in single or combined treatments. Frequency of main mutations was considerably higher after combined treatment compared to single treatment. Combined treatment with 150 Gy and 0.01% NMU caused a hyper-additive mutation effect (4.76%), double the theoretically expected one, The chemical mutagen concentrations had considerable influence on the effect of the combined treatment. The mutation spectrum also differed in various kinds of treatments. Significant changes in the mutagen efficiency occurred with the increase of EMS concentrations in combined treatment with gamma-rays. The highest efficiency coefficient (3.65) was obtained in the variant with 40 Gy gamma-rays and 0.2% EMS, which correlates with the highest mutation frequency 7.88%). The highest efficiency coefficient was obtained when LD40 doses of die two mutagens were applied, The obtained hyper-additive effects caused higher genetic variability in pea and to a large extent increased the possibilities for screening of mutants with useful breeding traits, Mutagen lines with economically useful characters were obtained.