Effect of drought stress on the yield and composition of volatile oils of drought-tolerant and non-drought-tolerant clones of Tagetes minuta

A drought-tolerant clone of Tagetes minuta L. (Asteraceae) was selected in vitro on a medium containing 60 mM mannitol. In the greenhouse, a decrease in soil field capacity (FC) from 100 to 40% reduced oil yield by 49, 71 and 71% for drought-tolerant, nondrought tolerant cloned and seed-grown plants, respectively. in soil at 40% FC, the drought-tolerant clone had the highest leaf dry weight and oil yield. At 100% FC, there was no significant difference in leaf dry weight, but the drought-tolerant clone had a significantly higher percentage oil content and yield than seed-grown plants. The main components of the oil were monoterpenes of which trans- and cis-tagetone together were 52.3%-64.2%. Drought significantly altered the content of some oil components.