The dissertation substantiates, theoretically generalizes and solves the scientific problem, which is to create the original breeding material of tomatoes with a reduced duration of the growing season, high fruit quality, high lycopene content in fruits and environmental stability in terms of productivity.Experimental research on the topic of the dissertation was conducted during 2016–2020. Research and evaluation of the reliability of the obtained results were carried out using field, laboratory, genetic and mathematical-statistical methods, which provided an opportunity to draw reasoned conclusions. Of the dissertation the regularities of phenotypic variability of tomato traits were studied and generalized. In most cases, low and medium variability was detected. The hybrid combination Т–3627 / МО 112 (2.0–5.0 %) had an annual low degree of variability. The sign "average weight of marketable fruit" revealed a low degree of variability in parental forms and hybrids (65 cases) and in ten cases an average degree of variability. The sign "the number of marketable fruits per plant" revealed a low and medium degree of variability among parental forms and hybrids. Hybrid combinations with high variability of plant productivity indicators are selected. Promising group of source material from five tomato samples № 477 (sp, u), Alia (sp), Dark green (hp-2dg), MO 112 (hp), T-3627 (Bc) was selected by dialysis analysis. The highest effects of the general combining ability (GCA) in the length of the growing season during the three years of research were marked by the line № 477 (from minus 4.70 to minus 2.34), two years of research – the variety Alia (from minus 1.11 to minus 0.99). According to the content of lycopene in fruits during three years of research, samples of MO 112 (0.25–1.21) and Т-3627 (0.49–0.96) were noted. According to the average weight of marketable fruit, the best reliable effects of GCA during the three years of research were the variety Alia (from 11.69 to 18.11), the number of marketable fruits on the plant during the two years of research – line № 477 (1.16–2.32) and sample Dark green (1.29–1.78), which indicates the viability of their use to create heterosis hybrids and varieties. It was found that the traits "duration of the growing season", "lycopene content in fruits", "average weight of marketable fruit" and "number of fruits per plant" are controlled by the additive-dominant genetic system. The main role in the genetic control of traits "lycopene content in fruits" and "average weight of marketable fruit" was played by additive effects of genes, which makes it possible to make selections starting from the second hybrid generation. Non-additive (dominant) effects of genes prevailed in the genetic control of the traits "duration of the growing season" and "number of fruits per plant". Promising forms for breeding for high content of lycopene in fruits with high breeding value on this basis are selected: samples MO 112 (7.32 mg / 100 g); T–3627 (4.87 mg / 100 g) and Dark green (3.50 mg / 100 g). The highest breeding value for the number of marketable fruits on the plant had combinations: Dark green / №477 (11.3 pcs.); Dark green / MO 112 (10.9); № 477 / Dark green (10.9 pcs.); MO 112 / Dark green (10.9 pcs.); Alia / MO 112 (10.36 pcs.) and Dark green / Alia (10.3 pcs.). The highlights the results of the evaluation of new tomato breeding material: two promising lines (LK 280 and LK 283) with a reduced fruit ripening period and increased lycopene content in the fruit; a collection of 25 hybrid combinations was created, of which 50 samples were selected in the F3 breeding nursery and 13 in F4 for breeding of new lines; detailed characteristics of the newly created varieties Spalakh, submitted to the State variety test (application № 21115003 from 14.01.2021), and Bagrianets (being prepared for transfer), which contain lycopene in fruits of 7.9 and 9.0 mg / 100 g, respectively, have a period of vegetation duration 101 and 105 days, respectively, which provides a commodity yield of up to 65.3 and 46.1 t/ha, respectively.
