Effects of Cycocel and Irrigation Regimes on Some Physiological Parameters of Three Olive Cultivars

Problem statement: The water deficiency is one of the serious problems, in the arid zones. Cycocel by increasing the stomata resistance and decreasing transpiration can help to water use efficiency. Approach: In this research the impacts of different doses of Cycocel (0, 500 and 1000 mg L^-1) and irrigation regimes (33, 66 and 100% of available water; referred to as I₁, I₂ and I₃, respectively) on some physiological parameters of three olive cultivars (Baghmalek, Fishami and Dezfuli) were investigated. The experiment design was factorial split in completely randomize. Measured parameters included fresh and dry weight of root and stem, root length, leaf area, Relative Water Content (RWC), stomata resistance and ratio of total fresh and dry weight of shoot to root. Results: Results showed that drought stress decreased stem fresh weight from 24 g for well Irrigated (I₁) compared to 17.5 g for drought stress treatment (I₃). Fishami cultivar indicated highest fresh and dry of stem (28.15 and 16.52 g), leaf (12.97 and 9.44 g) and root (25.34 and 7.99 g respectively) compared to other two cultivars. Olive plants in I₃ treatments had higher stomata resistance (46.05 sec cm^-1) and lower RWC (54.92%). C₃ treatment resulted in highest stomata resistance (28.18 and 42.81 sec cm^-1 measured in the morning and at noon, respectively); the corresponding values for C₁ treatment were 22.26 and 28.93 sec cm^-1. Conclusion: Results suggested that I₂ and cv. Fishami were superior compared to other irrigation treatments and cultivars. Cycocel adjusted drought neutralized negative effects of drought stress.