Highly heritable heartwood properties of Scots pine: possibilities for selective seed harvest in seed orchards

The stilbenes pinosylvin (PS) and its monomethyl ether (PSM) provide natural decay resistance to Scots pine (Pinus sylvestris L.) heartwood timber. For growing trees, the inducible stilbene production serves as a defence against biotic and abiotic stresses. To improve the potential of reforestation material to produce stilbenes, we assessed the possibilities of selective harvesting from seed orchards. Half-sib progenies growing in a field trial and their grafted mothers in seed orchards were surveyed for several chemical and dimensional heartwood characteristics. The correlations between the clonal means of grafted mothers and the family means of their progenies were high for concentration of PS (r = 0.83, p = 0.000) and PSM (r = 0.60, p = 0.010) and for heartwood density (r = 0.72, p = 0.001). For these traits, the narrow-sense heritabilities (h(2)) estimated from the progeny trial and the broad-sense heritabilities (H-2) in seed orchards were high as well. For the concentration of PS, both h(2) (0.67) and H-2 (0.81) showed the highest values of any trait. The selective collection of Scots pine seed from seed orchards is a promising way to obtain seedlings that possess genetic potential for active defence and to produce high-quality heartwood as mature trees.