An approach for the mass propagation of Cupressus sempervirens L. (Cupressaceae), for quality propagule production

The scenarios of climate change in Mediterranean regions bring back the need for tree species tolerant to drought and disease, for agro- and urban-forestry purposes, landscape rehabilitation, as well as for post-fire and quarry restoration plans. Therefore, forest industries focus on selecting, propagating and growing superior trees. The Cupressus sempervirens L. is such a coniferous tree species, with a fundamental ecological, financial and ornamental role in the Mediterranean region. The aim of this study was to develop an efficient macropropagation protocol, which would lead to mass-selected genotypes or phenotypes of C. sempervirens f. sempervirens. For this purpose the axillary shoot multiplication method was used, by adopting both cutting propagation and intermittent mist methods. These methods were used for the first time in the macropropagation of C. sempervirens f. sempervirens. For shoot proliferation, 24 different modified macropropagation treatments at different concentrations and combinations were tested: shoot cuttings, concentrations of K-IBA and rooting systems. The elongation and root induction was carried out in an intermittent mist system for 50 days, then the new plantlets were moved for acclimatization for 15 days in a greenhouse. The current workflow presents an effective preliminary protocol with clear steps and treatments for macropropagation of C. sempervirens f. sempervirens. The developed protocol for macropropagation of tree species ensures cost- and time-efficient propagation. Produced plantlets were developed efficiently under in vivo conditions, allowing to propagate and store genetic material for conservation and domestication. This protocol can be generated for other tree species of the Cupressus genus and the Cupressaceae family.