OBTAINING PLANTING MATERIAL OF HYBRID CHERRY VARIETIES BY THE CLONAL MICROPROPAGATION METHOD

The aim of research is to improve the technology of clonal micropropagation of hybrid cherry varieties at the stages of micropropagation, rooting and adaptation. Research was carried out in 2023–2024 in the laboratory of plant biotechnology of the N.V. Tsitsin Main Botanical Garden of the RAS. The following hybrid cherry varieties were used in the experiment: Carmine Jewel, Valentine, Cupide and Pamyati Levandovskogo. Explants of the varieties Carmine Jewel and Valentine were characterized by the maximum number of microshoots (from (3.2 ± 0.7) to (3.4 ± 0.6) pcs.) and the multiplication coefficient (from 6.2 ± 1.0 to 6.5 ± 1.2), while those of Pamyati Levandovskogo were minimal (the number of microshoots was (1.9 ± 0.2) pcs., the multiplication coefficient was 3.2 ± 0.8). The use of nutrient media according to the prescriptions of Murashige-Skoog (1962) (MS) and Quoirin-Lepoivre (1997) with a full concentration of macrosalts was effective for clonal micropropagation of cherries compared to variants with ½ concentration of macrosalts: the number of microshoots was from (3.1 ± 0.7) to (3.3 ± 0.9) pcs., the height of microshoots was from (18.5 ± 1.1) to (19.4 ± 1.3) mm, the multiplication coefficient was from 6.7 ± 0.9 to 7.2 ± 0.9. The growth regulator 6-BAP at a concentration of 0.3 mg/l or 0.5 mg/l 6-BAP together with 0.3 mg/l mT in the nutrient medium contributed to the maximum implementation of the morphogenetic potential (the multiplication coefficient varied from 8.0 ± 0.7 to 8.4 ± 0.6). The influence of the genotype, mineral bases of the nutrient media and growth regulators on the rooting of cherry explants was determined. Cherry varieties can be arranged in ascending order according to rooting: Cupide (10 %), Valentine (21), Pamyati Levandovskogo (34), Carmine Jewel (48 %). Cultivation of explants on 1 : 2 MS nutrient medium with the addition of 0.5 mg/l indolebutyric acid promoted active rhizogenesis in microshoots of most cherry varieties (rooting rate of 46 %). The effect of illumination and temperature on the rooting rate of microshoots of the ‘Carmine Jewel’ variety was established. Lowering the temperature to 15 °C and maintaining illumination of 1500 Lx for 7 days and then raising the temperature to 25 °C at the rhizogenesis stage promoted an increase in the percentage of rooted microshoots (63 %). For successful adaptation of the Carmine Jewel and Valentine regenerants, the rooting stage is necessary.