Optimization of the Technology of Clonal Micropropagation of Varietal and Wild Hops

The studies were conducted in 2024 to optimize the initiation stage of primary sterile culture and expand the in vitro collection of climber hop (Humulus lupulus L.) using clonal micropropagation. The effect of disinfectants (2% lysoformin-3000 and 30% hydrogen peroxide) and the carbohydrate composition of the Murashige-Skoog medium (10 to 40 g/L glucose or sucrose) on the disinfection efficiency and viability of primary explants of ten genotypes of varietal and wild hops has been studied. The effectiveness of five successive cuttings of sterile shoots of in vitro culture has been assessed. The use of 30% hydrogen peroxide has increased the yield of aseptic explants to 83.7%, or by 21.1%, compared to the treatment of the initial material with 2% lysoformin-3000. The proportion of proliferating axillary buds depended on the genotype (determination coefficient = 0.72) and varied from 60.2 to 100%. An increase in the amount of carbohydrates to 30–40 g/L in the nutrient medium has stimulated the development of infection by reducing the effectiveness of sterilization and viability of microshoots by 8–30% compared to the concentrations of 10–20 g/L. Cultivation of explants on a medium containing 20 g/L of glucose promoted an active development of existing meristems and the formation of new nodes, which resulted in the formation of an average of 1.4 cuttings per shoot for genotypes in the zero passage, which was 2–7 times higher than their number in the variants using other doses of sugars. The multiplication coefficient of samples in vitro consistently increased from the first to the fifth passage, reaching 8.0 cuttings/shoot at the final stage. The predominant contribution to the variability of the trait has been made by the “subcultivation frequency” factor (84%). In wild forms, the increase in the average values was maximal between the second and third passages, reaching 2.6 and 5.8 cuttings/shoot, respectively. In cultivated samples, the trait stabilized one generation later (4.0 and 8.0 in the third and fourth passages, respectively).