Cultivation and Characteristics of Licorice F1 (Glycyrrhiza glabra x G. uralensis) Lines

Abstract

Licorice, a traditional Korean medicinal plant, is recognized for its main active ingredient, glycyrrhizin. The level of glycyrrhizin in Chinese licorice (Glycyrrhiza uralensis ) is lower than the reference level (2.5%) set by the Korean Pharmacopoeia, reducing its value as a medicinal herb. In this study, we aimed to overcome this problem by generating an interspecific licorice hybrid by crossing European licorice (G. glabra ) with Chinese licorice, resulting in the production of 32 F1 lines. A comparison of genetic traits revealed variations in glycyrrhizin content among lines, ranging from 1.5 to 5.6%, with a mean value of 3.2%; these values are higher than that of the parental plants. Additionally, 25 lines (78.1%) had a glycyrrhizin content greater than 2.5%, which is higher than the reference level set by the Korean Pharmacopoeia. Four of these lines had glycyrrhizin levels higher than the WHO recommended level of 4.0%. A comparison of phenotypic characteristics showed that the leaves of the hybrids possessed all of the characteristics of European and Chinese licorice; however, the stems of most hybrids had characteristics of European licorice. Finally, we determined the genetic distances of 34 samples of Glycyrrhiza plants (parents, 32 F₁ lines) by random amplified polymorphic DNA (RAPD); the F₁ lines showed a close genetic distance. We plan to develop to a cultivar using five of these lines (glycyrrhizin content < 4.0%).