effect of different concentrations of iba (indulebutyric acid) hormone and cutting season on the rooting of the cuttings of olive (olea europaea var manzanilla)

objective: in order to study the effect of different concentrations of iba hormone on rooting of olive cuttings in spring and winter of 2012-2013 in a greenhouse in jiroft, iran. methods: a split-plot experiment was conducted on the basis of a randomized complete block design in which hardwood cuttings of one-year-old olive plants cv. manzanilla with the diameter of 0.7-1 cm were used. the main plot was devoted to cutting seasons at two levels of spring (late-may) and winter (late-january) and the sub-plot was devoted to iba (indulebutyric acid) hormone treatment at five levels of 0, 1000, 2000, 3000 and 4000 ppm. results: it was found that 3000 ppm iba increased the number of roots, the percentage of rooted cuttings, branch length, and root:shoot fresh weight. in traits such as root length and root dry weight, the highest effect was observed under the treatment with 4000 ppm iba. but, control treatment had the lowest effect on the traits of rooting in olive cuttings. cuttings planted in spring showed the highest effect on their evaluated traits (by 10-15%) with a significant difference with those planted in winter. the interaction between hormone and planting time was significant only for root fresh weight.