Different grafting techniques and deployment strategies for improved genetic materials of stone pine, Pinus pinea, offer more landowners the possibility to consider the tree as a viable crop. The stone pine is an emblematic tree that produces Mediterranean pine nuts, the most expensive nuts in global markets due to their scarcity.

The event, organised by the Wild Nuts and Berries iNet of the INCREDIBLE project, was held at in the National Centre of Forest Genetic Resources in Madrid and was attended by public and private forest nursery practitioners and technicians from forest administrations, forest owners’ associations, enterprises and research centres in Spain and Portugal.

Invited speakers were specialists and technicians from the Spanish Ministry of Agriculture, the National Institute of Agricultural and Food Research and Technology, regional forest administration, and forest nurseries involved in obtaining and deploying elite clones selected for outstanding cone production, aimed as scion donors for grafted plantations.

The event transmitted advances in genetic improvement of stone pine for pine nut production. In Spain, the first 15 elite clones have been registered as basic materials after years of evaluation in common garden trials, while Portugal has a registered clone mixture.

The main issue, however, concerned grafting techniques used for this pine. While in milder oceanic climate zones like Portugal or Southwest Spain, direct in-field grafting is feasible if skilled technicians are available, for harsher climates like inner Spain, nursery-grafted treelets for outplanting are the preferred option. Another advantage for planting grafted trees is that it is a key-in-hand solution, expanding stone pine as a possible crop for landowners who are inexperienced themselves in grafted stone pine and who do not have access to skilled grafters. Other aspects analysed included nursery techniques and costs.

After establishing mother tree plantations producing graft scions, forest nurseries will be able to supply the sector with grafted trees.