Object of study: regularities of manifestation of abiotic and biotic factors; assessment of genotype – environment interaction; productive and adaptive potential of barley; breeding and genetic features by parameters of genetic variation and combining ability; breeding progress on yield and stability; genetic gain in yield elements of structure. Methods: field, laboratory, and statistical. Results: As a result of implementation of the main provisions of the dissertation, barley varieties have been created. They are nine winter barley varieties, six of which Atlant Myronivskyi, Paladin Myronivskyi, MIP Yason, MIP Hladiator, MIP Oskar and MIP Darii have been included in the State Register of Ukraine in 2014–2018; three varieties are under the qualification examination at Ukrainian Institute for Plant Variety Examination (UIPVE); as well as fifteen spring barley varieties of various types of use (grain and brewing), of which eleven ones Talisman Myronivskyi, Virazh, MIP Myrnyi, MIP Saliut, MIP Sotnyk, MIP Azart, MIP Bohun, MIP Visnyk, MIP Myroslav, MIP Ekspert, MIP Vdiachnyi have been entered into the State Register of Ukraine in 2016–2018 and four varieties are under the qualification examination at UIPVE. As a result of determining the breeding and genetic peculiarities gene pool of winter and spring barley for adaptive breeding was formed. It is includes 2125 accessions derived from 52 countries, including 589 winter barley accessions and 1536 spring barley ones. The systematic diversity covers 58 varieties belonging to two groups (hulled and naked) and two subspecies (two-row and six-row). Within this gene pool, four collections have been identified and registered in the National Centre for Plant Genetic Resources of Ukraine (NCPGRU). Novelty: In complete diallel schemes of crossing of modern barley varieties, breeding and genetic patterns for elements of production. Approaches as to determining frost resistance of winter barley integrated into the developed conceptual scheme of evaluation and selection of winter barley breeding material for frost resistance increase were optimized. Effectiveness in the breeding practice of a systematic approach to determining the drought tolerance of barley breeding lines using laboratory and laboratory-field methods in different periods of plant development and the final field testing for yield using statistical indices have been revealed. It has been substantiated and experimentally proved that conducting multi-environment tests in different ecological zones of Ukraine (Central Forest-Steppe, Northern Step and Polissia) and data analysis using a number of statistical stability indices, AMMI and GGE biplot models contributes to in-depth assessment of genotype-environment interaction and identifying "the best of the best" breeding lines at the final selection stage. Use of different sowing dates in winter barley breeding process has been proved to be simple but effective approach. Field of use: agriculture.
