Comparison of growth characteristics and quality of Korean ginseng (Panax ginseng C.A. Meyer) using different shade materials

Abstract

Production methods for high-quality ginsengs for various advanced medical applications of today and the future are developing continuously. This research project aimed at exploring the growth of Panax ginseng at different microclimate-changes induced by using different shading materials and by analyzing the ginsenosides produced in P. ginseng grown under different shading material. The temperatures under the shading materials from June to October was high in order of Blue polyethylene sheet (BPS) > Aluminium-coated polyethylene sheet (ACPS) > Three-layered blue and one-layered black polyethylene net (TBOBPN). Particularly BPS showed the highest light transmission of 381.7µmol/s/m2 in August, which generated high temperature in the ginseng field. The growth of aerial parts from the 2 – 3 year old ginsengs were vigorous in order of TBOBPN > ACPS > BPS, whereas BPS with high light transmission rate also allowed strong growth of 4 year old ginsengs. Root growth in terms of root length and root diameter by different shading materials was satisfactory, regardless of root age, in the order of ACPS > BPS > TBOBPN. More specifically, root length was 23.2 cm longer for 2 year-old roots, 28.3 cm longer for 3 year-old roots, and 29.3 cm longer for 4 year-old roots in the plots treated with ACPS compared to TBOBPN and BPS plots – and root diameter showed the same results as root length. However, the root weight was essentially identical for the three shading materials for all age groups, except for the 4-year old root of ACPS-shaded ginseng that showed 2.96 kg dry material per 1.62 m2 field, i.e., about 8% increase in yield compared to the plot shaded with TBOBPN. The content of ginsenosides Rg2, Rf, Re and Rd in the plot treated with ACPS was higher than in both BPS and TBOBPN plots. Thus, the total ginsenoside content of 4-years-old roots was 20.92 mg/g dry material for ACPS-shaded ginseng and 20.38 and 15.89 mg/g dry material for BPS-shaded and TBOBPN-shaded ginseng, respectively.