Efficient vegetative propagation of various clones of mastic tree (Pistacia lentiscus 'Chia') through rooting of shoot cuttings

Pistacia lentiscus ‘Chia’ (mastic tree), which produces the special resin known as mastic gum from the wounded trunk, is cultivated extensively on the Greek island of Chios. For new plantations, clonal propagation is desirable which, however, faces difficulties in rooting of shoot cuttings. The aim of this work was to investigate the rooting ability of shoot cuttings for mass production of young plants. From four very common cultivated clones of high productivity in resin (mastic gum), named ‘Psilofyllos’, ‘Votomos’, ‘Fardis’ and ‘Maroulitis’, semi-hardwood leafy cuttings, 10-12 cm long, were cut (in winter, spring, summer and autumn) and treated with K-IBA at concentrations of 0, 4, 8 or 16 g L^‑1 in water solutions. The cuttings were then planted on medium consisting of a mixture of perlite and peat (2:1, v/v) in boxes and transferred to the fog system for rooting. In another experiment conducted in winter, cuttings were treated with 4 g L^‑1 of K-IBA and placed for rooting in boxes with three different media consisting of perlite and peat, in ratios of 1:0, 2:1 and 1:1 (v/v), enriched with 0, 10 or 20 g L^‑1 of CaCO₃. Application of K-IBA at concentrations of 4 and 8 g L^‑1 increased cutting rooting, with maximum rooting in winter (80%) and minimum in spring (17.5%). In addition, at these concentrations more and longer roots were formed. The use of plain perlite enriched with 20 g L^‑1 CaCO₃ increased the rooting percentage but not the number and length of roots. Plant genotype influenced the rooting ability of the cuttings, with ‘Psilofyllos’ to achieve the highest rooting percentage (80%) as compared with ‘Votomos’, ‘Fardis’ and ‘Maroulitis’ (52.5, 40 and 15%, respectively).