Extending and maintaining the in vitro collection of (inter)national hop varieties in Ukraine

Despite the decline in the national hop production, a part of hop products, made of Ukrainian aroma hop, is highly estimated in the international market and exported. Therefore, a relevant prerequisite of ensuring a suffi cient level of competitiveness of domestic hop production is the expansion of its assortment. To satisfy this need the breeders face the task of creating varieties with unique characteristics, which requires searching for new forms and strains of hop with increased content of different biologically active compounds in cones. In this regard national research program aimed to investigate genetic stab ility of hop varieties during multiple planting and storing of explants in in vitro conditions while introducing them into the collection, adapting the composition of Murashige and Skoog culture medium for specifi c varieties is discussed. Studies conducted included the analysis of plants by morphological and variety-specifi c traits, the identifi cation of varieties by biochemical criteria, improvement of hop regenerants using ELISA, molecular-genetic analysis based on PCR (polymerase chain reaction) for identifi cation of hop genotypes and determination of genetic stability, and the improvement of method of microclonal reproduction of hop. As a result of the perennial research of cultivating hop planting material using the Murashige and Skoog complex of nutrients, the foundations of creating and maintaining the in vitro collection of hop varieties were fi rst elaborated in Ukraine which allow for the possibility of decreasing the concentration of nutrients in the culture medium by 50 %, replacing expensive gel-forming preparation for the maintenance of plants in the culture medium - agar-agar, the share of whose cost in the medium composition is up to 70 %, with a cheaper substance - modifi ed starch DDKamod or agroperlite, and reducing the expenses for the maintenance of genetic pool in the in vitro collection. It was determined that the spectra of microsatellite loci of the amplifi ed DNA of the explants, cultivated in vitro, during the study period did not differ from the spectra of plant DNA prior to cloning, which demonstrated DNA stability and allowed cultivating hop varieties in the in vitro culture without any changes in the genome. The composition of media for cultivation and long- term storing of hop varieties in in vitro conditions was selected.