Adaptation of Humulus Lupulus L. Regenerants to Ex Vitro Conditions

The purpose of the study is to develop a scheme for two-stage adaptation of regenerated plants of common hop (Humulus lupulus L.) to ex vitro conditions using a hydroponic installation. Objectives: to study the influence of the method of fixing hop regenerants in a hydroponic system; to determine the duration of the adaptation stage in hydroponics; to select the substrate composition at the second stage of adaptation. The object was a sterile culture of common hop of three varieties: Tsivilsky, Flagman and Taurus, after completion of the in vitro rooting stage on a nutrient medium according to the Murashige-Skoog recipe (MS) containing glucose (20 g/l) and IBA (0.5 mg/l). The duration of the adaptation stage of hops rooted in vitro in a tidal-type hydroponic system was determined, identified by the stable maintenance of turgor by leaves and active growth of shoots – 18–21 days. The influence of the method of fixing hop regenerants in a hydroponic system was studied: the use of seedling cassettes with a substrate of perlite and vermiculite (1 : 1) showed a 25 % higher survival rate of plants compared to substrate-free cuvettes with liners made of polyethylene film. It was shown that under hydroponic installation conditions, regardless of the fixation method, the height of the shoots increased by 36.0–48.3 %. The root system of the samples adapted in cassettes with substrate was better developed and was characterized by a large number of 2nd order roots with a length of at least 4 cm. The subsequent stage of adaptation in most peat-containing substrates ensures 100 % survival and the production of high-quality planting material. Recommendations for growing hop planting material after two-stage adaptation are presented.