Response of tow olive cultivars (Mary and Mission) to exogenous cycocel treatments under drought stress

In order to investigate the effect of cycocel on different growth aspects of two olive cultivars (Mary and Mission), a greenhouse experiment was conducted taking into account three factors of: cycocel at three levels (0, 500 and 1000 mg L-1), drought stress of three levels (irrigated at 5, 10 and 15 days intervals) and two olive cultivars (Mary and Mission) in a factorial experiment based on randomized complete block design of three replicates during four months. The results showed that both cycocel treatments decreased leaf area, increased leaf thickness, chlorophyll content and soluble sugars, but no significant difference in leaf temperature was observed compared with the control. High cycocel treatments (1000 mg L-1) increased proline and relative water content (RWC) compared with the other treatments. Also, results showed that increased periods of drought reduced leaf area, RWC, but increased leaf thickness, leaf temperature, chlorophyll content, proline and soluble sugars in both cultivars. In above-mentioned parameters, 'Mission' showed higher resistance to drought stress than 'Mary'. Results suggested that cycocel treatment can neutralize some negative effects of drought stress in 'Mary' and 'Mission' of olive trees.