Object: Grain hardness variability in winter bread wheat, its inheritance patterns in F1 and F2 hybrid seeds, relationships between structural and mechanical composition of endosperm and valuable economic features. Objective: Determination of genetic diversity of Triticum aestivum L. in terms of grain hardness, selection of valuable soft-grained sources, establishment of inheritance patterns of grain hardness, relationships between structural and mechanical composition of endosperm and valuable economic features and development of holistically valuable soft-grained wheat lines on this basis. Methods: General scientific, specific, genetic-statistical. Novelty: Determination of genetic diversity of Triticum aestivum L. in terms of grain hardness and development of starting material of winter bread wheat, establishment of its inheritance patterns in F1 and F2 hybrid seeds, relationships between structural and mechanical composition of endosperm, creation of holistically valuable, high-yielding lines, which differs from previously known results by a systematic approach to evaluation of grain hardness of accessions. For the first time in Ukraine, grain hardness of winter bread wheat accessions were expressed in newtons for different hardness groups. Soft-grained accessions with highly stable 1000-grain weight and yield were identified. Accessions with high homeostaticity and regression coefficient (bi <1) in each grain hardness group were determined. Positive correlations between features of structural and mechanical composition of endosperm were found. The influence of female components on endosperm hardness of F1 hybrid seeds with saturating nature was evaluated, and inheritance types of grain hardness of F1 hybrid seeds were defined. Grain hardness segregation types in F2 hybrid seeds were determined. Known positive correlations between valuable economic features in winter bread wheat were confirmed for soft-grained accessions, and their influence on yields was assessed. In addition, correlations between them were calculated for soft-grained accessions. Results: The efficiency of grain hardness evaluation in winter bread wheat accessions on a force hardness meter YPD - 300 D was evaluated. Fifteen sources with valuable features for confectionery industry were selected; 4 of them are soft-grained with small flour particles, and 11 - with low water absorption capacity (WAC). Twenty-eight soft-grained sources with high levels of valuable economic features (7-9 points) were identified. A trait collection of winter bread wheat based on grain hardness and confectionery properties was formed and registered. Twelve holistically valuable soft-grained winter bread wheat lines were developed and transferred to the NCPGRU. A soft-grained variety of winter bread wheat, Mazurok, was created in co-authorship (5%) and submitted to the state variety trials. The express-method of estimation of grain hardness of winter bread wheat in the field by effort for grain cutting and mealiness was improved. Degree of Implementation: The soft-grained lines created and sources and check accessions selected have been introduced into breeding and scientific programs of such research institutions as the Plant Production Institute named after V.Ya. Yuriev of NAAS of Ukraine, V.M. Remeslo Myronivka Institute of Wheat and Plant Breeding and Genetic Institute - National Center of Seed and Cultivar Investigation. Scope of Implementation: scientific institutions of NAAS, NAS and the Ministry of Agrarian Policy and Food of Ukraine, higher educational establishments, agrarian enterprises of Ukraine.
