The interaction effect of water stress and manure on yield components, essential oil and chemical compositions of cumin (Cuminum cyminum)

Water stress enhances essential oils content in medicinal plants. Manure in soil prepares essential elements and increase quality and quantity of plant products. To study the effects of water stress and manure application on yield components, oil percentage and its main constituents on Cuminum cyminum, this experiment was conducted at the Agricultural Research Station of Zahak, Zabol, south east of Iran in a complete randomized block in factorial design with four replications. Treatments including irrigation intervals (I(1): two times irrigation, I(2): three times irrigation and I(3): four times irrigation that are irrigation in germination, seedling, flowering and seed filing stages) and manure application (F(1): without manure application, F(2): 20 t/ha manure application). The chemical composition of the essential oil was examined by GC and GC-MS and they were significantly affected by water stress and manure (P<0.05). Three irrigation times with manure treatment produced the highest number of umbrella per plant, seed and biological yield and the lowest 1000 - seed weight and number of seed per umbrella. The effect of water stress and manure were significant on essential oil and its constituents. Three irrigation times with manure treatment caused the highest amount of cumin aldehyde and rho-cymene and the lowest of beta-pinene, gamma-terpinene and alpha-pinene. Results showed that a relationship exist between the main constituents of cumin essential oil under water and manure application.