Improving water use efficiency through drought stress and using salicylic acid for proper production of Rosmarinus officinalis L.

Drought stress often reduces plant growth. Therefore, in order to decrease the negative effect of drought stress on rosemary growth and prevent its severe reduction, an experiment was carried out through drought stress treatments along with increasing tolerance and quality of plant using salicylic acid in 2014 at the Research Institute of Forests and Rangelands (Iran) under field conditions. The experiment was conducted as split-plot in a randomized complete block design with three replications. The main factor included drought stress at three levels of 30 % (severe stress), 60 % (mild stress) and 90 % (control) of field capacity, and the subfactor was the salicylic acid foliar application at four levels of 0, 1, 2, and 3 mM. According to the results, the most suitable levels of stress and salicylic acid treatments for the production of essential oil was 60 % FC and 1 as well as 2 mM salicylic acid, respectively. Rosemary is one of the most drought tolerant plants with an annual consumption of 4500 to 5500 m3 of water per hectare in a growth period. Also, a mild stress – 60 % of the field capacity- would be produced the optimum production of this plant.