Purpose. Comprehensive study, selection, evaluation and systematization of self-pollinated lines of maize (Zea mays L.) obtained on the basis of material of diffe­rent genetic structure from endosperm of flint and dent maize were implemented according to the main economically valuable traits and precocity in order to select the best genotypes for selection. Methods. Hybridization, inbreeding were used in the process of creating the initial material; visual method – for phenological observations; laboratory and field – to determine the morphobiological characteristics of self-pollinated lines of maize; measuring and weighing – to account the harvest and determine the metric characteristics of plants; mathematical and statistical – to determine the validity of the results, indicators of trait variability, correlation dependence of traits; analysis of variance; comprehensive assessment of morphobiological and economically valuable traits of self-pollinated maize lines of the most common germplasms. Results. As a result of assessment of self-pollinated lines of the most common germplasms, it was revealed that the highest level of grain yield was obtained under both sowing periods – Iodent germplasm; the minimum grain moisture content – Flint and Mix germplasms; the shortest average duration of the emergence – flowering of 50% of male and female inflorescences stage – Flint germplasm; steadily high va­lues ​​of plant height for germplasm Mix – under the optimal sowing date, and Iodent plasma – under the late sowing date. Steadily high values ​​of the ear insertion height at both sowing dates were obtained for lines based on Iodent germplasm. The number of the most precocious and the best by the economically valuable traits germplasms of self-pollinated lines were identified. Conclusions. The DK239 lines – Flint germplasm, DK7174, DK2285, DK305, DK2613, DK5568 – Iodent germplasm, DK2332 and DK2659 – Mix germplasm were the most precocious and the best by the economically valuable traits. They are promising for the selection of ultra-early hybrids of maize adapted to the conditions of the Steppe of Ukraine.