The Effect of Irrigation Intervals on Quantitative and Qualitative Yields of Two Savory Species (Satureja khuzestanica and S. rechingeri)

Satureja khuzestanica and satureja rechingeri are two valuable and endemic medicinal species that grow widely in southwest parts of Iran. These species are rich in phenolic compound caracole; therefore, they have considerable biological activities. In order to evaluate the quantitative and qualitative yields of two savory species (Satureja khuzestanica and S. rechingeri) in different irrigation intervals, an experiment was carried out in the west of Lorestan (Kashkan) during the growing season of 2012-2013.
The Experiment was conducted on the basis of split-plot design in completely randomized block design with three replicates. Irrigation treatments (15 and 30 days interval and rainfed) as the main-plot and species in two levels (Satureja khuzestanica and satureja rechingeri)as the sub-plot were carried out. The characteristics measured were leaf and flower yield, essential oil content, essential oil yield, essential oil compositions, leaf area index and plant height.
Results showed that the effect of irrigation treatments on all traits except for essential oil compositions was significant. The effect of species on essential oil content and essential oil yield was significant. Mean comparison of traits showed that by increasing in irrigation intervals, leaf and flower yield, essential oil content, essential oil yield, leaf area index and plant height of both summer savory species were decreased amount of by 73, 23, 78, 80 and 33%, respectively compared to control (Irrigation interval of 15 days). Between species, essential oil content (3/7%) and essential oil yield (100/2 kg.ha-1) of rechingeri species were more than essential oil content (2/03%) and essential oil yield (62/2 kg.ha-1) of khuzestanica species.
The leaf and flower yield, essential oil content, essential oil yield, leaf area index of both summer savory species were decreased by increasing irrigation intervals and rainfed cultivation. Trend of changes in essential oil yield was similar to leaf and flower yield, In other words, the essential oil yield was further affected by the herb yield (leaf and flower yield).