Purpose. To reveal the frequency and intensity of callus formation and organogenesis, the effectiveness of microclonal reproduction of various species of the genus Linum L. (Linaceae) in vitro. Methods. For in vitro induction of callus formation and organogenesis, hypocotyl segments of species Linum usitatissimum L. convar. elongatum and convar. usitatissimum, L. tenue Desf., L. bienne Mill., L. corymbulosum Pchb., L. nervosum Waldst. & Kit., L. flavum L., L. campanulatum L., L. perenne L., L. austriacum L., L. grandiflorum Desf., L. strictum L. were cultivated on Murashige and Skoog medium supplementedwith 0.05 mg/l 1-naphthylacetic acid and 1.0 mg/l 6-benzyl aminopurine at 22–24 °C, relative humidity of 60–80%,with 16 hours photoperiod (2500 flux). For microclonal reproduction Murashige and Skoog, White, Gamborg and Eveleigh media and their modifications were used. The measurement results were interpreted by the arithmetic mean, standard error for the sample mean, the leastsignificantdifference and ranked. Results. Different species of the genus Linum to a large extend are capable of forming callus and regenerating shoots under the specified cultivation conditions. The frequency of callus formation for the studied samples on the 35th day of cultivation varied within 81.25–100%, the mass of callus from one explant – 0.21–1.64 g, the frequency of organogenesis – 12.50–100%, the number of shoots – 1.8–7.6 pcs. and the height of the shoots was 0.82–2.12 cm. The following species: L. usitatissimum convar. elongatum, L. tenue, L. bienne and L. strictum were distinguished by a high intensity of callus formation. Intensive organogenesis was pecular to L. tenue, L. bienne, L. flavum, L. austriacum and L. grandiflorum. The efficiency of somaclone obtaining was quite low in L. nervosum and L. campanulatum. In total, for the microclonal reproduction of species of the genus Linum Murashige and Skoog, Gamborg and Eveleighmedia supplementedwith 12.5 g/l glucose were optimal. At the final stages of microclonal propagation, before transferring microclones in vivo, it is advisable to use White medium, which contributes to a high frequency of rhizogenesis. Varieties of L. usitatissimum convar. elongatum and convar. usitatissimum had diffe­rent responses to in vitro culture. Conclusions. The frequency and intensity of callus formation and organogenesis, the effectiveness of microclonal reproduction depended on the genotype of a particular species; therefore it is advisable to select the composition of the nutrient medium and growth regulators for each of them. Some species of the genus Linum have not yet been studied in vitro, so the obtained results allow expanding the scope of their use in practice, in particular in breeding as a new source material with somaclonal variation, interspecific crosses, and ornamental floriculture.

Purpose. To determine the content of biochemical compounds in fruits of M. domestica Borkh. varietal samples, select the most promising ones for use in further breeding, and recommend for use in various directions, given the biochemical complex of signs, taste and marketability of the fruit. Methods. We used generally accepted methods for determining the biochemical composition of fruits (soluble so­lids (SSR) according to GOST (State Standard System) 29030-91, total sugars according to GOST 8756-13.87; polyphenol composition according to the method of L. I. Vigorov (1968), vitamin C according to the method of A I. Ermakov (1972); tit­rated acids – according to GOST 25555.0-82). Results. Nine cultivars of apple trees were analyzed for the biochemical composition of fruits, namely the apple tree cultivar ‘Vydubytska Plakucha’ (‘V. p.’) and various hybrids created on its basis from the collection of the fruit plant acclimatization department of the M. M. Hryshko National Botanical Gardens of National Academy of Sciences of Ukraine. Selected forms are sources of 1–5 important biochemical characteristics (solids content, glucose, sugars, ascorbic acid, titratable acid) and promising for use in breeding. According to the dry matter content – the lowest rate was found in hybrid ‘V. p.’ × ‘Renet Symyrenko’ (16.68%), the highest in the hybrid – ‘V. p.’ × ‘Renet Oranzhevyi Coksa’ (22.87%), rates of ascorbic acid content varied within (6.0–12.25 mg%), total sugars (10.37–18.23), acids (0.74–1,67 respectively). The most interesting for introduction and breeding are hybrids with a high content of biochemical parameters, namely: ‘V. p.’ × ‘Renet Oranzhevyi Coksa’, ‘V. p.’ × ‘Golden Delicious’ and ‘V. p.’ × ‘Parmen Zymovyi Zolotyi’. Conclusions. The content of the biochemical composition of the fruits, taste and marketability were characterized, and varietal samples of hybrids of the apple tree ‘Vydubytska Plakucha’ were distributed in the directions of use in order to improve the quality of life of the population. According to the biochemical indicators of the cluster analysis of the studied apple hybrids, close relationships were found between the three groups necessary in the future for breeding when selecting parental forms for an improved biochemical composition of the fruit (including hybrids ‘V. p.’ × ‘Renet Oranzhevyi Coksa’, ‘V. p.’ × ‘Golden Delicious’ and ‘V. p.’ × ‘Parmen Zymovyi Zolotyi’, titrated acid hybrids ‘V. p.’ × ‘Starkrimson’, ‘V. p.’ × ‘Parmen Zymovyi Zolotyi’ and ‘V. p.’ × ‘Renet Symyrenko’, tannins hybrids ‘V. p.’ × ‘Slava Peremozhtsiam’ and ‘V. p.’ × ‘Starkrimson’); and to expand the assortment of apple trees according to the planned commercial signs. Hybrids of the apple-tree cultivar ‘Vydubytska Plakucha’, created in the NBG using old and valuable modern apple-tree cultivars, indicate the promise of producing high-yielding, large-fruited varieties with a high content of biologically active substances