Object: patterns of performance and grain quality traits in corn lines, correlations, combining ability and mechanisms of their genetic control. Objective: to establish performance and corn grain quality traits depending on genotypic and environmental factors, as well as of combining ability; to create collections with different levels of characteristics and types of adaptive responses. Methods: general scientific, field, biochemical; measuring and weighing, genetic-statistical, statistical. Novelty consists in establishing the variability of performance and grain quality in corn lines depending on genotypic and environmental factors, determining the value of accessions of different geographical origin, subspecies and ripeness groups in terms of performance and grain quality, describing peculiarities of correlations between the performance and grain quality traits in corn lines, building up trait collections. Genotypic levels and variability of major biochemical effects of endosperm mutations and peculiarities of their influence on other indicators of grain quality and performance have been determined. The types of adaptive responses of corn lines have been defined by genotypic effect and parameters of ecological plasticity for the traits of grain productivity and quality. Peculiarities of the amino acid composition of grain proteins have been established and groups of lines of various nutritional value of protein have been distinguished. Parameters of the combining ability of corn lines under various environmental conditions and their influence on the heterosis level have been determined. Peculiarities of genetic control and types of inheritance of the traits of grain productivity and quality in corn hybrids have been revealed. Results: on the basis of the conducted research, corn lines belonging to different ripeness groups with stable response to weather factors have been identified; five trait collections of corn have been formed according to biochemical composition of grain, performance and its elements. The collections have been registered with the National Center for Plant Genetic Resources of Ukraine. Corn lines with high general and specific combining abilities and hybrid combinations with a high level of heterosis have been identified; they are recommended for further testing in heterosis breeding. Seeds of the best lines have been propagated and laid for medium-term storage in the National Depository. Seven corn hybrids with a high starch content (Zorianyi, Elitnianskyi, Mavka, Vektor, HA Bolid, Hopak, and Darunok) have been created and included in the Register of Plant Varieties Suitable for Dissemination in Ukraine. Degree of Implementation: the best inbred lines have been involved in breeding programs of the Plant Production Institute named after VYa Yuriev of NAAS, Synelnykivska Breeding and Research Station of the State Institution “Institute if grain Crops” of NAAS, Ustymivska Experimental Station of Plant Production of the Plant Production Institute named after VYa Yuriev of NAAS, Institute of Irrigated Agriculture of NAAS; seven hybrids, which are included in the State Register of Plant Varieties Suitable for Dissemination in Ukraine, have been bred. Scope of Implementation: scientific institutions of NAAS, NAS and the Ministry of Agrarian Policy and Food of Ukraine, educational establishments, agrarian enterprises of Ukraine.
