Somatic plant regeneration from selected common cypress (Cupressus sempervirens L.) clones resistant to the bark canker disease

The effectiveness of a protocol for somatic embryogenesis in conifers requires both the proliferation of embryonal masses and their conversion into somatic plants. Despite several successful protocols developed for Pinaceae, species belonging to Cuperessaceae family are often characterized by a problematic and unsatisfactory maturation of somatic embryos. Hence, the main goal of this study was to overcome the problem of embryo maturation and plant regeneration in Cupressus sempervirens, a Mediterranean species widely used for its ornamental value, timber production and interest in reforestation programmes. Embryogenic lines were produced from selected canker-resistant genotypes of common cypress; the effect of polyethylene glycol (PEG), desiccation period, medium composition and culturing period on the somatic embryo maturation and conversion, were evaluated. Despite significant variations observed among genotypes, the PEG based medium was the most effective for somatic embryo maturation. Germination and conversion of mature somatic embryos took place after three months of culture in a low-sucrose LP medium with activated charcoal. A short desiccation period failed to improve the germination rate of the mature somatic embryos. To our knowledge this is the first protocol reporting on somatic plant regeneration from somatic embryos of C. sempervirens.