The research was carried out during 2019–2022 in the conditions of the Right-Bank Forest-Steppe of Ukraine at the botanical site of the Department of Landscape Gardening of the Uman National University of Horticulture. During the research, meteorological indicators differed by year, which makes it possible to better evaluate varieties and newly created source material by key indicators. The research scheme provided for the study of introduced rose varieties, selection of parental components for breeding, and rose propagation by various methods, including biotechnology. The resulting hybrids were studied according to generally accepted methods.Research on the inclusion of a biotechnological link in rose breeding has shown that sodium hypochlorite is the most effective sterilizing agent with an exposure of 20 minutes – 90 %, sterilization efficiency and the yield of sterile viable explants is 92 %. The best period for in vitro introduction of explants during the initial phase and active vegetation of intact plants is March–July.
The culture media with optimal concentrations of growth regulators for proliferation and rhizogenesis were selected. The best genotypes were identified; among those selected for clonal micropropagation with the largest number of micropropagules formed are Tchaikovski (6.50) and Koralovyy syurpryz (6.27). The best average rooting frequency of rose varieties was obtained with the use of 0.5 mg/l IВА (3-indolylbutyric acid) and 1.0 mg/l IВА - 91.2 % and 90.2 %, respectively.
The best substrate for the ex vivo rooting stage, where the efficiency of adapted plants reaches 98 %, was selected: peat, turf soil and perlite (1 : 1 : 1).
When studying the resulting hybrid populations, it was found that most varieties transmit certain traits in the same way, regardless of which component is the variety (maternal or paternal). In most cases, the inheritance of a trait depends on the genotype of the original varieties.
The dominance score and heterosis in first-generation hybrids were analyzed. Compared to their parents, the studied offspring usually had negative true and hypothetical heterosis. The degree of dominance (hp) in most hybrids had negative overdominance (hp < -1) by quantitative indicators. Among the combinations, hybrids H5, H6, H18 and H26 had the highest positive heterosis (Hip and Hspr) for the studied parameters. Among all the hybrids of the first generation, negative heterosis for all indicators was found in 31.3 %.
Among the combinations, hybrids H5, H6, H18 and H26 had the highest positive heterosis (Ghyp and Gtrue) in terms of indicators. Among all the hybrids of the first generation, negative heterosis for all indicators was found in 31.3 %.
The acclimatization number for hybrids was calculated. Most of them had 92 and 95, and hybrids H4 and H16 had 79. However, these limits, according to the methodology, correspond to good adaptation of plants to the conditions of the Forest-Steppe of Ukraine.
The resistance of hybrids to the most common diseases was studied. Seedlings had the best resistance to rust, black spot and powdery mildew: H3, H7, H11, H17, H19, H20, H24, and H32. In the future, these hybrids can be used both for a breeding program for resistance and can be implemented for landscaping an urbanized environment.
A comprehensive evaluation of the hybrids was calculated and it was found that the average score for the varieties was 77.2 points. The lowest score was observed for hybrids H19 and H32 - 58 and 56 points, respectively. These hybrids are not recommended for implementation in green building, but these combinations have good indicators of resistance to biotic and abiotic factors, so they can be introduced into the breeding process. Hybrids H1, H3, H5, H7, H8, H9, H11, H13, H20, H22, H23, H24, H26, and H30 had the best comprehensive score and exceeded 80 points. These hybrids are quite promising for use in green building. They can also be used in the breeding process as carriers of decorative and biological indicators.
Key words: rose, varieties, hybrids, introduction, morphology, phenophases, flowering, fruiting, comprehensive assessment, decorativeness, stratification, scarification, clonal micropropagation, inheritance of traits.
