Paving the way for commercial somatic embryogenesis : Norway spruce in Finland

Somatic embryogenesis (SE) has been recognised to have vast potential to produce improved reforestation material. By applying SE, genetic gains achieved by breeding can be utilised fully and faster than by seed orchard approach. Yet, there are only a few commercial mass-propagation applications in conifers. Challenges include biological, economical, and regulative issues together with stakeholder and public acceptance, and these are discussed in the case of Norway spruce (Picea abies (L.) H. Karst.) SE propagation in Finland. In Norway spruce, biological issues related to SE have been mostly solved, as highlighted by recent developments such as high initiations rates, high recovery from cryopreservation, and short in vitro germination, all applicable to genetically wide materials. The current SE stock at Natural Resources Institute Finland (LUKE) exceeds 5600 genotypes, derived from the top trees of the Finnish tree breeding program. Also, development of automation to improve cost-efficiency has proceeded successfully; a robot prototype has been developed for in vitro germination phase in collaboration with South-Eastern Finland University of Applied Sciences (XAMK). LUKE registered the first Norway spruce SE basic material for forestry in 2017, as the first one in Europe, and propagation pilots have been carried out since 2018. The whole SE propagation pipeline has been developed to fit into regulative framework, being compatible with international (European Union, Organisation for Economic Co-operation and Development) and national regulations for the production and marketing of forest reproductive material. Views of forest owners and professionals on spruce SE propagation have been studied, and their wishes for desired/value-added traits in the improved material taken into account. Further, concerns related to loss of genetic diversity and lack of information are being addressed by genetically wide stock of SE materials, development of robust methodology, and information openly available. However, more effort is still needed for public discussion.