Dihaploid lines, or lines obtained on the basis of doubled haploids, are a valuable material for the creation of high-heterosis corn hybrids. The most eff ective method of evaluating the starting material when selecting parental couples for obtaining hybrids is diallell analysis. The article presents the results of the analysis of indicators of 6 dihaploid corn lines and 30 simple corn hybrids of the dialle scheme. The combinative ability of lines along the stem length, the cob attachment height, and the panicle length was studied. The eff ects of the GCA and SCA dispersion, as well as the components of genetic dispersion for the above characteristics were revealed. Lines with high GCA and SCA rates were identifi ed. The variation of the indicators of combinative ability during the years of the study indicates that the degree of strength of the eff ects of GCA and the dispersion of SCA morphometric parameters in certain lines varies to some extent under the infl uence of growing conditions. The analysis of the components of genetic dispersion showed that, depending on the growing conditions, the formation of stem length was infl uenced by 1 to 3, cob height by 1 to 3, and panicle length by 1 to 2 genes or groups of genes. A pattern has been revealed: in more favorable conditions in 2021 and 2023, the number of genes that control the manifestation of the stem length and the panicle length traits increases. A signifi cant impact of dominance components (H1 , H2 ) has been established. Dominance in stem length, ear height and panicle length is directed towards the parental forms with greater expression of the trait.