Cultivated licorice plants (Glycyrrhiza uralensis FISCH.) contain smaller amounts of the triterpene saponin glycyrrhizin than wild licorice plants. To resolve this problem and to breed strains with high-glycyrrhizin content we determined the glycyrrhizin content of 100 samples of G. uralensis that were propagated from seed and grown under the same conditions in the field for 5 years. There was a 10.2-fold variation in glycyrrhizin content among these plants, ranging from 0.46 to 4.67% (average 2.11±0.90%). There was also a wide variation in liquiritin content, ranging from 0.11 to 2.65% (average 1.00±0.49%). The glycyrrhizin content was positively correlated with that of liquiritin in the taproots (r(2)=0.5525). Our results indicate that there are various genetic strains for glycyrrhizin and liquiritin synthesis within a population of plants propagated from seed. The selected high-glycyrrhizin and liquiritin strains will be useful for licorice production and studies on biosynthetic analysis of glycyrrhizin and liquiritin.