Vegetable and corn crops have significant place in agricultural production for ages. Contemporary agriculture requires from produced varieties to provide relatively high yields. This task is related to problems of rational harvest, proper protection against pests, provision of good storage and then processing. That is why the problem of awareness of physical and chemical properties of particular seed species becomes more and more important. Presently, some particular attention should be paid to their electric properties because of wide applications of electric energy in developing and sustainable agriculture. Among methods which directly use this energy some can be distinguished: sorting and drying of seeds, protection against pests (incl. disinsectization), microwave processing of grain and treatment by radio frequencies, processed fruit pasteurization, dielectrics seasoning of timber, electrode heating of water, electrostatic precipitation in mills and dust material mixing, etc. This work presents a method to determine some electric properties of grain (dielectric constant, resistance) and test results of the influence of electric field and mechanical stress on these properties. This research results and the awareness of mutual correlations between the influence of electric field and mechanical stress on electric properties of material of biological origin arc important and useful for teams of engineers and designers of devices in agri-food industry. They contribute to create and develop new techniques in agri-food processing making use of the influence of electric field on materials of biological origin. These problems arc particularly important in the southern-eastern region of Poland, which is agricultural and industrial. Many companies dealing with agricultural crop processing, individual farms and individual electric energy users related to this industry can take the advantage of these results for positive and sustainable development of the region.