Object: Peculiarities of inbred corn lines in terms of morpho-biological traits, performance, variability and combining ability depending on their genetic origin and of experimental hybrids derived from them. Objective: To evaluate the breeding value of inbred corn lines of different genetic origin for valuable economic traits and combining ability; to justify selection of lines for heterotic hybrids depending on their genetic origin and performance features; to establish optimal combinations of genotypes to create high-yielding hybrids. Methods: general scientific, field, special, laboratory, mathematical/statistical. Novelty consists in establishing the peculiarities of inbred lines for a set of valuable economic traits with their high and stable expression depending on genetic origin of lines. The selection value of inbred lines derived from starting material, which was diverse in morphology, performance and its elements, combining ability, resistance to bio- and abiotic factors, has been assessed; lines suitable for mechanized harvesting and donors of valuable economic traits have been identified; relationships between the performance characteristics in the corn lines have been determined; ways of the performance formation in the corn lines and hybrids derived from these lines have been outlined; lines with natural expression of CMS traits (sterility fixers, pollen fertility restorers) have been identified. Results: Based on the study results, two working collections by cob length and plant performance have been built up and registered with the National Center for Plant Genetic Resources of Ukraine. Sources of group resistance to pathogens have been identified. Lines UKhL 226, UKhL 257 and UKhK 364 have been registered with the National Center for Plant Genetic Resources of Ukraine (NCPGRU) of the Plant Production Institute named after VYa Yuriev of NAAS. The following lines with high combining ability have been distinguished: for performance (UKhL 257, UKhL 337 and UKhK 364); by the kernel number per cob (UKhS 57 and UKhL 289); by 1000-kernel weight (UKhS 226, UKhL 218 and UKh 1008); by a set of performance traits (UKhL 373). Four pollen fertility restorers (UKh 144, UKh 1008, Kharkivska 803 and UKhL 303) and 28 M-type sterility fixers have been found. Three mid-early corn hybrids (Liubchyk (FAO 240), Stavr (FAO 290) and Vektor (FAO 270)) have been created and included in the State Register of Plant Varieties Suitable for Dissemination in Ukraine. Two hybrids are being tested in the state variety trials (under the qualification examination): mid-early KhA Bolid (FAO 280) and mid-ripening Novator (FAO 320); in 2020, two hybrids were submitted for the qualification examination: mid-early Hart (FAO 280) and mid-ripening Arho (FAO 300). Degree of Implementation. The best inbred lines have been involved in breeding programs of the Plant Production Institute named after VYa Yuriev of NAAS, Synelnykove Breeding Experimental Station of the Institute of Irrigated Agriculture of NAAS, Transcarpathian State Agricultural Experimental Station of NAAS, Institute of Irrigated Agriculture of NAAS; three mid-early hybrids have been bred and included in the State Register of Plant Varieties Suitable for Dissemination in Ukraine. Scope of Implementation: research institutions of NAAS, NAS and Ministry of Agrarian Policy and Food of Ukraine, educational institutions, Ukrainian agrarian enterprises.
