Application of In Vitro Techniques for Propagation of Rosa Kazanlika Top. (Rosa Damascena Var. Trigintipetala)

ABSTRACT

Studies were conducted on in-vitro propagation of the Kazanlak oil-bearing rose cv. Iskra, with the objective of accelerating the production of vegetative planting material. The following main traits, responsible for the micropropagation efficiency, were treated: date of sterile culture establishing, explant types, disinfection methods, nutrient media suitable for multiplication and rooting, adaptation to in-vivo conditions. A comparative study was also made on the behaviour of in-vitro propagated plants under field conditions in terms of their flower yield and essential-oil quality, as compared to those of plants produced through softwood cuttings. Optimum development of microplants—good viability, fresh foliage, and possibility of longer subcultivation were achieved by using shoot tips from apical buds, established in sterile culture during the May-July period. The best disinfection of the initial planting material was obtained by the application of 0.1 % mercuric chloride for 5 mins (80–100 % sterile viable cultures). At the stage of proliferation, the best result—fresh, green, viable plants with high (for Rosa Kazanlika) multiplication rates, was achieved in MS medium, supplemented with 0.5–1.0 mg/l BAP. Comparatively most favourable conditions for rhizogenesis induction were obtained in the MS medium, containing NAA and reduced mineral element composition. The percentage of plants, suitable for adaptation, was 81.8 %. A high percentage of successfully transplanted plants (over 80 %) from rooted microplants under in-vivo conditions was also registered. The studies on the morphology, growth, development, flower yield and essential oil quality in the in-vitro propagated plants showed that the values of the traits observed were not inferior to those of conventionally propagated plants.