Pre-sowing electro-stimulation of seeds of perennial ryegrass was carried out in the corona electric field. Its influence on seed and fodder productivity of the stimulated seed material was defined. It was determined that given treatment may serve as a physical mutagen while breeding perennial grasses. Mutant forms of two varieties of perennial ryegrass in the second generation were studied. The results obtained give us grounds to affirm that pre-sowing perennial ryegrass seed treatment in the corona electric field is effective not only for use in seed production as a measure of raising its sowing and productive qualities. It may also serve as a high-potential selective method for increasing fodder and seed productivity, provided that the initial material for breeding of new intensive varieties of this kind will be created. It has been proved that the optimum regime of seed electro-stimulation for breeding material of perennial ryegrass is electric field intensity (E = 3.3 kW cm^-1), exposure (30 sec.) and time of seasoning (5 days). The method provides an opportunity to widen the spectra and frequency of induced mutant variability in subsequent mutant generations according to economically valuable characteristics, and to increase the efficiency of breeding valuable cultivars. Due to the results of the study it has been determined that the intensity of the electric field, exposure time and time of seeds seasoning in all the variants led to an increase of heterogeneity of field populations structural organisation in a number of consecutive generations.