The genetics of artemisinin content in Artemisia annua L. and the breeding of high yielding cultivars.

Artemisinin, the endoperoxide sesquiterpene lactone produced by the Chinese medicinal herb Artemisia annua, is very difficult to synthesise. Moreover, its production by mean of cell, tissue or organ cultures is very low. Presently, only its extraction from cultivated plants is viable. A large variation in artemisinin content has been observed in the leaves of plants from different origins. The genetic basis of this variation has been assessed and evidence for a quantitative inheritance of the artemisinin concentration presented. Additive genetic components were predominant, resulting in a high narrow-sense heritability estimate. Thus, goods results can be expected from mass selection for the breeding of lines of Artemisia annua rich in artemisinin. Yet, dominance variance is also present in the total genetic variability, indicating that crosses between selected genotypes should generate progenies with particularly high artemisinin content. As a matter of fact, selection and crossing, in wild populations, of genotypes with high artemisinin concentration resulted in hybrid lines containing up to 1.4 % artemisinin (on dry leaves basis).