Aim for production of Glycyrrhizae Radix in Japan (3): development of a new licorice cultivar.

The development of cultivars is indispensable for the establishment of a method aimed at producing licorice in Japan. The cultivar should have the following attributes: (1) the underground parts should grow vigorously; (2) the glycyrrhizin (GL) content must be 2.5 % or greater; and (3) the architecture of the aerial parts should be erect. A new cultivar suitable for the domestic production of licorice was developed by crossbreeding between strain A-19 (with a high GL content) as the mother and strain G-6 (with vigorous growth) as the father. After 2 years of cultivation, strain C-2 exhibited vigorous growth; the fresh weight and stem diameter were 148.8 g and 0.89 mm, respectively. Moreover, the dry-weight GL and total flavonoid contents of the new cultivar (strain C-2) from cultured plants were 3.61 and 1.365 %, respectively.