Comparative evaluation of rooting cuttings of five Mediterranean sage species (Salvia sp.) native to Greece

In the present study, we examined the effect of application method and concentration of indole-3-butyric acid (IBA) on the rooting of stem cuttings of five wild species of sage from Greece: Salvia fruticosa, S. officinalis, S. pomifera ssp. pomifera, S. ringens and S. tomentosa. The aim was to find an effective rooting method, along with obtaining mother plants and plant-clones with desirable characteristics for future crosses to improve wild species for potential horticultural use. Shoot-tip cuttings, 12-15 cm long, collected from native plants in April to May 2019, were treated either with dusting powder Rhizopon (0.5% w/w ΙΒΑ) or their bases were dipped for 1 min in solutions of IBA (50% ethanol) at 0 (control) or 500 or 1000 or 2000 or 3000 (mg L^‑1). The cuttings were then placed for rooting on peat-perlite (1:1 v/v) in a mist for 2 weeks, and then remained on the greenhouse bench in a semi-shaded location for another 4 weeks. In all species, with the exception of S. officinalis, higher rooting (over 80%) of cuttings were observed after treatment with dusting powder or immersion in a 2000 or 3000 mg L^‑1 IBA solution compared to immersion in lower concentrations of IBA or the control. In S. officinalis, lower rooting percentages were generally observed compared to other species, probably because cuttings were in bloom and not sufficiently lignified. The best treatments for this species were immersion in a solution of 2000 or 3000 mg L^‑1 IBA, providing about 50% rooting.