Induction in vitro of adventitious morphogenesis in isolated tissues of the genus Rubus plants using cytokinins from adenine and diphenylurea groups

Abstract

The eff ect of cytokinins from the adenine and diphenylurea groups on adventitious organogenesis in vitro in isolated tissues of the genus Rubus plants was studied. Leaf explants and callus of red raspberry of the Volnitsa variety, blackberry of the Chester Thornless variety and the Rubus odoratus species were cultivated in the dark at a temperature of +25 ±2 °C on Murashige and Skoog medium. The medium contained 0.5 mg/l of gibberellic acid (HA), 0.5 mg/l of indolylacetic acid (IAA), and 6-benzylaminopurine (6-BAP) at concentrations of 0, 1, 2 and 4 mg/l or thidiazuron (TDZ) at concentrations of 0.1, 0.2 and 0.4 mg/l. The number of explants that formed adventitious shoots and the number of shoots per explant were taken into account. It has been established that for the induction of adventitious morphogenesis from leaf explants and calluses of red raspberry and blackberry the use of 6-BAP is more eff ective, thydiazuron is more eff ective for Rubus odoratus. The optimal concentration for 6-BAP is 2 mg/l and 0.2 mg/l for TDZ. Exceeding these concentrations of cytokinins can cause shoot vitrifi cation. For blackberry, it is possible to increase the content of 6-BAP in the medium for the induction of morphogenesis to 4 mg/l. The unequal ability to regenerate adventitious shoots in diff erent genotypes was revealed. In optimal variants of the experiment, the maximum frequency of their formation ranged from 13.3 % in Rubus odoratus to 40.0 % in blackberry. The use of the established optimal concentrations of growth regulators made it possible to obtain regenerated plants from callus that underwent long-term cultivation (for 10 months) on artifi cial nutrient media during tissue selection for tolerance to heavy metal salts and pesticides. Despite the reduced morphogenetic potential of tissues undergoing prolonged cultivation in vitro, 3 red raspberry regenerant plants and 1 Rubus odoratus plant were obtained from callus selected for tolerance to cobalt chloride. 9 blackberry plants and 7 red raspberry plants were regenerated from the tissues selected for pesticide tolerance.