Some distinctions between the inbred P346 line and five somaclonal Zea mays lines (UKCh-5, UKCh-6, UKCh-7, UKCh-8, and UKCh-9) obtained from it via tissue culture in vitro have been found through RAPD analysis. The somaclonal lines were shown to differ from each other by the magnitude of genetic distances from the original P346 line as well as by the level of intraline heterogeneity. Positive interrelationship was revealed between these indices. The subset of polymorphic amplicons which distinguish the somaclonal lines from the original one proved to be common for some of them. The results obtained along with the earlier studies on the individual phenotypic selection and genetic traits demonstrated that the employment of the tissue culture in vitro together with the appropriate selection methods allow attaining desirable genetic changes.