The effects of irrigated and rainfed conditions on vegetative yield and essential oil yield of two medicinal species, Satureja khuzistanica Jamzad and S. rechingeri Jamzad in North of Khuzestan

For comparison the growth characteristics and quantitative and qualitative yield of two summer savory species (such as Satureja khuzestanica and S. rechingeri) in response to rainfed and irrigated conditions، an experiment was carried out on the basis of split-plot design in completely randomized block design with three replicates in north of Khuzestan during growing season of 2012-2013. Irrigation treatments (15 and 30 days interval and rainfed) as main-plot and species in two levels (Satureja khuzestanica and satureja rechingeri) as sub-plot was carried out. The characteristics measured were fresh and dry yield، leaf and flower yield، essential oil content، oil yield، leaf area index and plant height. Results of variance analysis of traits showed that the effect of irrigation treatments on all traits except essential oil content and plant height was significant. Mean comparison of traits showed that in rainfed cultivation and by increasing in irrigation intervals، fresh and dry yield، leaf and flower yield، oil yield and leaf area index of both summer savory species were decreased amount of 54، 44، 55، 53 and 37%، respectively compared to control (Irrigation interval of 15 days)، but the essential oil content was increased by 6 percent. Fresh yield (3/14t/ha)، dry yield (1/82 t/ha)، leaf and flower yield (1/08 t/ha) and leaf area index (0/43) of specie of khuzestanica were higher than rechingeri specie، but essential oil content (3/7%) and essential oil yield (33/86 kg/ha) of Satureja rechingeri were more than Satureja khuzestanica.