Rysin A. Peculiarities of creating winter bread wheat source material with high productivity and grain quality potential in the Forest-Steppe of Ukraine.

The dissertation theoretically substantiated and solved an important scientific task of creating winter bread wheat source material with high potential of productivity and grain quality in environment of Ukrainian Forest-Steppe by the establishing the peculiarities of manifestation of biometric indicators in various periods of vegetation and yield components of varieties and breeding lines, level their variability and the degree of correlation between traits, the selecting sources for cross-breeding and identification of features of phenotypic manifestation, inheritance and correlations of valuable traits to increase the efficiency of selection and predict the appearance of transgressive forms in F2, F3. For the first time in the conditions of the Forest-Steppe of Ukraine, new varieties and promising breeding lines of winter bread wheat were identified which combine a high level of productivity and grain quality; the parameters of their variability were determined, and the part of sum square for genotype, year conditions, and sowing date on their formation was determined. Phenotypic correlations between plant productivity indicators have been revealed, which increase the efficiency of selection of valuable genotypes. The objectivity of the integral assessment of the adaptability of varieties and breeding lines based on parameters of stability and plasticity by elements of the production process has been proven. The principles of selection of parental forms for hybridization were established and a new source material with a high level of manifestation of valuable selection traits was created. Peculiarities of the formation of yield components and grain quality indicators based on types of inheritance in F1, F2, degree and frequency of transgressions in F3 hybrid combinations were studied. The practical significance consists in the selection of varieties and breeding lines of winter bread wheat with high adaptive potential of productivity and grain quality, which are recommended to be included in crossbreeding programs as parental components, and in the creation of F1 and hybrid populations F2, F3, which are studied in breeding nurseries at Winter Wheat Breeding Laboratory of the V. M. Remeslo Myronivka Institute of Wheat of the National Academy of Sciences of Ukraine and are transferred for study and involvement in the scientific and educational programs of higher education institutions of the Ministry of Education and Science of Ukraine and “Agrofirma “Kolos" LLC. The line ER 55023 has been selected, which is planned to be transferred to the Ukrainian Institute for Plant Varieties Examination for the state qualification examination as the new winter bread wheat variety MIP Palianytsia with a complex of valuable economic traits. The dissertation analyzes the current state of scientific research on the creation and introduction in agriculture of winter bread wheat varieties with a high potential for productivity and grain quality which are resistant to adverse environmental factors. It is known that the formation of highly productive forms is influenced by both the genetic characteristics of the variety and their interaction with soil and climatic conditions. An important role in this process is played by the selection of the source material. Currently, the peculiarities of the inheritance of the main yield components, qualitative indicators in the hybrid material and the influence of parental forms on the heredity of these traits have not been sufficiently studied. Research directions related to the search and selection of high-quality genotypes with stable productivity potential and their further use in breeding process to create new germplasm, which remains the main task of modern breeding, are substantiated.