Zygotic embryo culture is an efficient way to optimize in vitro growth in Panax ginseng

Abstract

Despite many studies on tissue culture of Panax ginseng, the propagation of cultivars is still dependent on seeds due to low survival rate of plants produced in vitro. Healthy in vitro grown plants guarantee high survival rates after they are transferred to soil, but limited information exists on the optimum medium for the in vitro growth of P. ginseng. In this study, zygotic embryo culture was used to develop an optimum medium suitable for in vitro cultivation of P. ginseng. After 4–6 months of culture, the aged aerial parts turned yellow, and the in vitro grown roots (IGRs) had thickened taproots with dormant rhizomes. The seedling growth was evaluated using various concentrations of sucrose and basal media at various strengths. Of the tested media, 2% sucrose and 1/3 strength SH medium showed superior results. Subsequently, IGRs were transferred to soil and evaluated for their morpho-anatomical characteristics. Furthermore, their plants were analyzed for genetic fidelity using molecular markers. IGRs showed outstanding morphological differences compared with conventionally grown 1-year-old ginseng roots; however, there was no difference in the sprouting and survival rate after soil transfer. 2-year-old IGRs deprived from the IGRs have intermediate properties between 1-year-old and 2-year-old root. Unlike the 2-year-old roots, the morphology of 2-year-old IGRs had shorter primary roots with several lateral roots. Despite the morpho-anatomical differences, molecular marker analysis also confirmed that the IGRs had genetic fidelity.