Clonal Micropropagation of Wild Berry Plants of the Genus Rubus

Cloudberry (Rubus chamaemorus L.) and arctic raspberry (Rubus arcticus L.) are highly nutritional and medicinal but lowyield berries, with some populations being on the verge of extinction. Micropropagation biotechnologies are cost-effective and may provide healthy and plentiful planting material for these valuable berries. Clonal micropropagation of cloudberry and arctic raspberry requires new methods adapted for Russian varieties. This research featured the effect of sterilizing agents on the survival rate of explants of R. chamaemorus and R. arcticus, as well as the effect of growth regulators in the nutrient medium on their organogenesis in vitro. Berries obtained from regenerant plants of R. chamaemorus (Arkhangelsk and Vologda varieties) and R. arcticus (Sofia and Galina varieties) underwent a biochemical analysis. Further research involved the effect of sterilizing agents and exposure time on the viability of explants, as well as the effect of the nutrient medium composition and the concentration of growth regulators on the development of microshoots and roots in vitro. In case of lateral buds, the highest survival rate of both types of explants (80–96%) belonged to the samples sterilized with 0.2% silver nitrate and 5% Lysoformin 3000 for 15 min. In case of etiolated shoots (79–100%), it was the samples treated with 0.2% silver nitrate, 0.01% Nika 2, and 5% Lysoformin 3000 for 10 min. The maximal total length of microshoots in R. chamaemorus (19.4–22.7 cm) was registered at 0.1 mg/L Cytodef in the Murashige and Skoog medium. The maximal total length of roots (46.0–56.6 cm) was obtained when the medium contained 0.5 mL/L indolylacetic acid. As for R. arcticus, the maximal total lengths of microshoots (22.4–22.8 cm) and roots (86.6–89.3 cm) occurred at the same concentrations of growth regulators on 1/2 Murashige and Skoog medium. In this research, Cytodef and indolylacetic acid applied in the process of clonal micropropagation of R. chamaemorus and R. arcticus made it possible to increase the yield of high-quality planting material for commercial plantations.