Abstract
Artemisia annua plants were selected from seed-grown plants in the season 1990/1991 according to the morphological characters previously identified as markers for high artemisinin production. These were micropropagated by in vitro techniques as previously described. The performance of these micropropagated clones and those of the seasons 1989-1991 was followed up after transfer to the field for two seasons. They were compared to the mother plants in terms of morphological characters and their content of artemisinin and related sesquiterpenes, as determined by reversed-phase HPLC. It was found that the identified morphological characters are suitable for selection of high artemisinin-producing clones of A. annua. Several micropropagated clones with relatively high contents of artemisinin and/or artemisinic acid are reported. The optimum time for the transfer of the micropropagated plants to the field in Riyadh was identified to be late October to early November. One to two years of maintenance in culture during micropropagation was consistant with the preservation of the plant's characters and sesquiterpenes contents. The parasite, Orobanche cernua Loefl. was identified as a root parasite of A. annua that may cause heavy losses in the biomass yield.