Протокол среднесрочного сохранения in vitro Humulus lupulus с использованием технологии инкапсуляции

Growing demand for hops with new organoleptic characteristics and improved agronomic performance provides a powerful impetus for the breeding of new varieties, which determines the need to create and maintain gene banks of the crop. Field gene banks are at great risk due to the threat of biotic and abiotic stress. The problem of preserving valuable germplasm can be solved by duplicating the gene pool in in vitro collections, one of the management tasks of which is to find ways to slow down the growth of crops. A protocol for the medium-term storage of Humulus lupulus has been developed, including all stages of propagule encapsulation technology: from the preparation of initial explants to their subsequent rehabilitation and restoration of regenerative capacity after deposition. The protocol has been successfully tested on four genotypes of varietal hops. For the first time, conditions for encapsulation of microcuttings have been selected that ensure their viability of at least 80 % after in vitro conservation at 4 °C. Treatment of the material with 3 % sodium alginate during the encapsulation stage, combined with 3 % calcium chloride during the polymerization stage, ensured high biocapsule survival. The optimal exposure time in the polymerizing solution did not exceed 10–15 minutes. It has been shown for the first time that 1 mg L-1 of abscisic acid in the artificial endosperm (AE) of biocapsules reduces the impact of cold stress during medium-term low-temperature storage of the material. Supplementing the Murashige-Skoog medium, which forms the basis of AE, with 2 mg L-1 6-Benzylaminopurine (BAP) and 1 mg L-1 Gibberellic acid (GA3) allows explants to form up to 3–4 internodes when cultivated immediately after deposition. Subsequent subculturing of hop microcuttings on MS nutrient medium containing 0.5 mg L-1 of kinetin promotes the restoration of photosynthetic activity in the regenerated plants. This approach ensures high regenerative and root-forming potential of emerging shoots over four successive cloning generations. The multiplication rate reaches 8–9 microcuttings per explant.