Relationship of artemisinin content of tissue-cultured, greenhouse-grown, and field-grown plants of Artemisia annua.

Artemisinin content of Artemisia annua L. plants grown under long days in a greenhouse was highly correlated (r = 0.931** and 0.954**, P = 0.01) with the same clones grown under long days in the field. The correlation of artemisinin content of clones grown in long days in tissue culture and in the greenhouse was r = 0.502*. Correlation of artemisinin content of tissue-cultured clones obtained two years apart was r = 0.61**. Broad-sense heritability estimates for artemisinin production based on vegetatively propagated clones derived from a random-mating population and grown in the greenhouse and field varied from 0.91 (greenhouse, individual basis) to 0.98 (combined greenhouse and field, family basis). These results indicate that genetic progress can be expected from intercrossing high artemisinin clones selected in the greenhouse under long days.