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Key message Molecular markers were used for paternity recovery in a maritime pine (Pinus pinasterAit.) polycross trial, facilitating forward selection. Different breeding strategies for seed orchard establishment were evaluated by comparing genetic gains and diversity. This work opens up new perspectives in maritime pine breeding.[br/] Context Polycross mating designs are widely used in forest tree breeding to evaluate parental breeding values for backward selection. Alternatively, polycross progeny trials may be used to select the best trees on the basis of individual breeding values and molecular pedigree analysis.[br/] Aims This study aimed to test such a forward selection strategy for the maritime pine breeding program.[br/] Methods In a maritime pine polycross trial, progeny with higher breeding values for growth and stem straightness was first preselected with or without relatedness constraints. After paternity recovery, the preselected trees were ranked on the basis of their breeding values, estimated from the recovered full pedigree. Finally, the best candidates were selected with three different strategies (forward, backward, mixed) and three levels of coancestry constraints to establish a virtual clonal seed orchard.[br/] Results Complete pedigrees were successfully recovered for most of the preselected trees. There was no major difference in expected genetic gains between the two preselection strategies which differed for relatedness constraints. Genetic gains were slightly higher for forward selection than for classical backward selection.[br/] Conclusion This seminal study opens up new perspectives for using forward selection within the French maritime pine breeding program. [br/]

International audience; Using our improved protocols for somatic embryogenesis in Pinus pinaster, transgenic tissues and plantlets were recovered after microprojectile bombardment (biolistic) or cocultivation of embryonal-suspensor masses (ESM) with Agrobacterium tumefaciens. Transformation experiments were carried out with selectable hpt gene (hygromycin B resistance) and reporter gus gene ($\beta$-glucuronidase activity). With both methods, hygromycin was shown to be an effective selective agent of transformed cells within 4-19 weeks. The mean number of hygromycin-resistant lines expressing gus per gram ESM subjected to DNA transfer, ranged from 7.0 to 8.5 using biolistic and 0 to 67.3 during Agrobacterium experiments. Mature somatic embryos obtained from some transformed lines were converted into plantlets and grown in the greenhouse. The whole process (from transformation to plant acclimatisation) could be completed within only 12 months. The transgenic state of ESM, somatic embryos and plants was confirmed by histochemical GUS assays and molecular methods.; Transformation génétique du pin maritime (Pinus pinaster Ait.). En appliquant nos protocoles d'embryogenèse somatique développés pour Pinus pinaster, des tissus et plantes transgéniques ont été obtenus après bombardement avec des microparticules (biolistique) ou coculture de masses embryonnaires (ESM) avec Agrobacterium tumefaciens. Les expériences de transformation ont été conduites à l'aide du gène de sélection hpt (résistance à l'hygromycine B) et du gène rapporteur gus (activité $\beta$-glucuronidase). L'hygromycine a permis de sélectionner efficacement les cellules transformées par ces deux méthodes en 4 à 19 semaines. Le nombre moyen de lignées résistantes à l'hygromycine exprimant le gène gus obtenu par gramme d'ESM varie de 7,0 à 8,5 (biolistique) ou de 0 à 67,3 (Agrobacterium). Les embryons matures obtenus à partir de certaines de ces lignées ont pu être convertis en plantules élevées en serre. Seulement 12 mois sont nécessaires de la transformation des ESM jusqu'à l'acclimatation des plantes. La nature transgénique des ESM, embryons somatiques et plantes, a été confirmée à l'aide de tests histochimiques " GUS " et de méthodes moléculaires.