Effect of Paclobutrazol on Adventitious Root Formation of IBA-Treated Cuttings of ‘Zard’ and ‘Dakal’ Olive ( Olea europaea L.) Cultivars

Abstract

Olive cuttings are difficult to propagate. They root well using synthetic auxin, indole-3-butyric acid (IBA). To evaluate the rooting and viability of olive semi-hardwood cuttings of ‘Dakal’ and ‘Zard’ cultivars in response to application of growth retardant, paclobutrazol (PBZ), and interaction of IBA and PBZ, a greenhouse experiment was conducted in 2012. Cuttings were dipped for 30 minutes in PBZ (0, 1000, 2000, and 4000 mg.L -1 ) and for 50 seconds inIBA (2000 mg.L -1 ) solutions, respectively and then planted in a sandy bed of propagation under automatic mist system with 95% humidity and 20±5 o C base temperature. Results showed that cutting viability, percentages of rooted, callused and rooted plus callused cuttings and root growth parameters were higher in ‘Dakal’ cultivar than ‘Zard’ cultivar. The 2000 mg.L -1 PBZ treated cuttings had a higher cutting viability, rooting percentage, number of branches per cutting, shoot length, number of roots per cutting, root length and root fresh and dry weights than the control. It appears that the rooting of ‘Dakal’ cultivar can be substantially improved by the treatment of PBZ (included IBA).