Genetic control of differentiation processes in radish was studied in vitro on the level of morphogenic capacities of explants. We have shown that when cultured on hormone-free MS medium (Murashige and Skoog, 1962), isolated radish cotyledons can produce callus and/or roots. At the same time, excised seedling apices placed on MS medium supplied with exogenous cytokinin can form multiple shoots or crop-root-like structures. In our model, the ability of explants to undergo the above morphogenic events in culture under certain in vitro conditions was examined as a genetic marker. As forms tested, highly inbred radish lines maintained by tight inbreeding for 28-34 generations were used. We have shown that ability of excised cotyledons to produce callus is controlled by a single gene, while their root-producing capacity is under di-genic control with some additional influence of the cytoplasm. Analysis of inheritance of seedling apex capacity to produce crop-root-like structures in response to exogenous cytokinin led us to propose the interaction of three genes in control of this trait.