Clonal Micropropagation of the Essential Oil Rose Cultivar “Festivalnaya”: Morphology, Anatomy, and Microshoots’ Ploidy Level

The genus Rosa includes more than 200 species and 18 000 cultivars, which are used in floriculture, and they are also economically important due to the presence of essential oil, a source of natural aromatic components. Products (essential oil, rose oil, rose water, etc.) obtained from essential-bearing oil roses are used in the food, perfume, cosmetic, and medical industries. Traditional rose propagation is carried out by cuttings, grafting, or budding, which are complex and time-consuming processes. Biotechnological methods have become an alternative to the vegetative method of rose propagation. The main studies are aimed at selecting the mineral composition of culture media and concentrations of growth regulators, while the issues of structural and genetic stability of the material in vitro are still discussed. Therefore, the object of our work was to determine the optimal conditions for in vitro cultivation, structure, ploidy, and relative DNA content of essential oil rose “Festivalnaya” microshoots. It was shown that the Murashige and Skoog culture medium containing 1.0 mg/L 6-benzylaminopurine and 1.0 mg/L kinetin was effective for the propagation of the material. Structural analysis of microshoots after cultivation for 12 months showed qualitative and quantitative changes caused by specific in vitro conditions and rejuvenation of the material. The ploidy of nuclei in leaf cells in vitro did not differ from that of shoots ex situ as did the relative DNA content (2.21 and 2.24 pg, respectively), indicating a certain stability of the material in vitro.