Investigating the Effect of Physical and Chemical Treatments on the Rate of Rooting of Iranian and Imported Olive Cultivars Cuttings under Bottom-Heat and without Bottom-Heat Conditions

Introduction: Olive (Olea europaea L.) encompasses numerous species and cultivars widely distributed as wild, naturalized, or cultivated trees and shrubs across vast regions of the world.Possessing a millennium-long history in Iran, this plant has been a crucial agricultural commodity and consistently holds substantial economic importance.Olive trees grow and develop well in Mediterranean climates, which feature temperate weather and mild winters.In recent years, the consumption of olives and their products has significantly increased in Iran, a trend expected to continue in the coming years.This rising demand necessitates expanding cultivation areas, developing horticultural programs, and establishing a source for producing new saplings to create new orchards and rejuvenate older ones.Propagating olive trees can be tricky, especially when it comes to rooting certain imported cultivars.This challenge has made it difficult for growers to expand production and meet demand for these popular plants.Rooting success is influenced by a mix of factors: the physical treatments applied to cuttings, the use of rooting chemicals like indole butyric acid (IBA), and environmental conditions, such as temperature.This study takes a closer look at how combining these approaches can improve rooting in four olive cultivars (Koroneiki, Koncervolia, Picual, and Zard) to make propagation easier and more reliable. Materials and Methods:This study was conducted as two separate experiments one with bottom heat and one without at the Tarom Olive Research Station (4905 E longitude, 3647 N latitude, 350 meters above sea level).Each experiment was arranged as a factorial design within a randomized complete block design (RCBD) with three replications.The factors included cultivar (Koroneiki, Konservolia, Picual, and Zard), plant growth regulator (indole-3butyric acid IBA at 0, 2000, and 4000 mg L), and physical treatment of cuttings (control, basal scratching, and basal splitting).Ten cuttings were used as a sample for each replication.Semi-hardwood cuttings, 18 to 20 cm in length, were collected from the selected cultivars between early and mid-December.Each cutting retained four leaves, and the remaining leaves were removed.To prevent fungal diseases in the rooting medium, carbendazim fungicide at a concentration of 1.5 g/L was applied.The basal ends of the cuttings were disinfected by immersing them in the same carbendazim solution for 10 to 15 minutes before planting.After treatment, cuttings were rinsed thoroughly with clean