effect of water stress and harvesting stages on quantitative and qualitative yields of coriander (coriandrum sativum l.)

in order to study the effect of drought stress and harvesting stages on quantitative and qualitative yields of coriander (coriandrum sativum l.) this experiment was conducted on split plot based on a randomized completely block design with 3 replications in torbat-e heydariyeh university, iran, during growing season of 2010-2011. treatments were drought stress (in three levels no stress: control and irrigation in 60 and 30 percentage of fc) as main plots and harvesting times (in 3 levels consist of: before flowering, flowering and after flowering) as sub plots. results showed that drought stress and harvesting stages had significant affected on leaf number, height, number of stem, wet and dry weight of plant, spad, proline content, carbohydrate content, essential oil yield and percentage and components of essential oil of coriander. increasing water stress decreased yield and its components while enhanced proline and carbohydrate contents. maximum of essential oil and its main components (linalool, alpha pentene, gamma terpinene, geranial acetate and camphor) were in low stress that had significant difference with other stress treatments. delaying in harvest enhanced yield and its components and essential oil percentage. proline content had no significant difference between flowering and after flowering stages. therefore, we can suggest low stress of water and harvest at after flowering stage to get maximum of yield.