Effect of water deficit stress on yield, essential oil and some of physiological traits in different ecotypes of Thymus daenensis subsp. daenensis in Karaj region

In order to study the effect of water deficit stress on yield, essential oil and some of physiological traits in different ecotypes of Thymus daenensis subsp. daenensis, an experiment was performed as split plot design based on RCBD with three replicates, in Karaj (2013). In this experiment, eight ecotypes of this plant were studied under three water deficit treatments including normal irrigation, stop irrigation at the start of flowering and stop irrigation at the vegetative stage. Result indicated that ecotypes under the different level of irrigation showed different responses for essential oil percentage, dry matter yield, chlorophyll, carotenes, proline and activity of catalase, glutathione peroxidase, and polyphenol oxidase enzymes. Close correlation was not observed between essential oil percentage and dry matter yield with chlorophyll, carotene, proline, and enzymes activity. The highest dry matter yield (17.27 gr per plant) was obtained in Malayer Bala ecotype under normal irrigation and the highest essential oil percentage (6.2 %) was obtained in ecotype of Malayer2 under stop irrigation at the vegetative stage. The highest essential oil yield as the most economical important was found in ecotype of Arak under the both stress treatments.