Experimental verification of some quantitative results, following from the new theory for investigation of non-allelic genes' interactions in the diallele analysis by Hayman was conducted. We postulated earlier a special kind of epistasis HC which is the new explication of epistasis j--the interaction between homozygote and heterozygote by Mather and Jinks. Genetic interpretation of the epistasis HC establishes some relations between epistasis and the model of ecological-genetical control of quantitative characters. We found the invariant characteristic of genetic control which is stable in a number of characters, environments, treatments, inspite of redetermination of genetic formulae under conditions of environmental variability.