The thesis presents a theoretical generalization of and a new solution to an important scientific problem of establishing variability patterns of breeding-genetic quantitative characteristics of spring barley cultivars and lines depending on genotype and growing conditions, based on which the goal to evaluate 22 cultivars and lines as starting material for ‘quantitative characteristics of plants and economic features’-oriented breeding was achieved. The results, in comparison with the known ones, are distinguished by comprehensiveness of solving the problem via different breeding and genetic methods for determinations of levels, variability, correlations, path coefficients, inheritance, combining ability, stability, and GGE biplot-value of breeding and economical characteristics, by optimal combinations of different varietal, breeding and economic features in spring barley cultivars and lines, by selection of sources of breeding-valuable traits under various growing conditions as well as by creation of breeding-valuable lines evolved from these sources.
For the first time, differences in morpho-biological quantitative characteristics were determined in 22 spring barley cultivars and three lines belonging to different varieties (13 nutans Schubl., five inerme Coern., four nudum L., one rikotense R. Red., one submedicum Orl., and one duplialbum L). under the comparative conditions of 2018–2020 Based on this, genotypes with high values of quantitative traits with weak or average variability were identified: for plant performance (grain weight) – cvs. Amil, Yavir, Avhur, Merlin, Margret, KWS Bambina, Krechet and Herkules (as line 14-561); for productive tillering capacity – cvs. Troian, Herkules and line 15-1246; for the grain number from the main spike – cvs. Amil, Sviatomykhailivskyi, and Hatunok, lines 15-1246 and 15-139 Modern, Grace Quench: for 1000-grain weight – Khors, Troian, Reserv, Sviatomykhailivskyi, Datcha and Gladys; for the grain weight from the main spike – cvs. Troian, Yavir, Herkules, Margret; for the grain weight per afterspring – cvs. Krechet, Akhiles, Khors, Amil, Hatunok, Troian, and Herkules and line 15-1246; for the main spike length – cvs. Grace, Hatunok, Akhiles, Krechet, Herkules, and Modern, Sviatomykhailivskyi, lines 15-1246; for short stems – cvs. Gladys, and Merlin. These cultivars and lines are valuable starting material for breeding for high values of the specified quantitative characteristics of plants.
The obtained results are of practical importance for spring barley combination breeding. Owing to defining peculiarities of spring barley cultivars and lines in terms of levels, optimal combinations, variability, correlations between quantitative traits, path analysis of the performance, inheritance and combining ability for the performance, genotype-environment interaction, and to genotype ranking by yield, its stability and relation to the «ideal genotype», the efficiency of evaluation of the starting material value for breeding was ensured.
