In Northern Finland as well as in Northern Sweden there is a shortage of high-quality Scots pine (Pinus sylvestris L.) seeds, mostly due to unsuitable temperatures during the development and maturation of cones and seeds. Methods have been developed for elimination of non-productive seeds and for invigoration of seeds. In the present work, these methods were tested on poorly developed seed lot from Rovaniemi, Northern Finland (66°15’–66°30’; 180 m a.s.l.). The seeds were conditioned using the following treatments:
1. PREVAC method (5 min, 97 kPa below atmospheric pressures) for removal of mechanically damaged seeds (7%)
2. Invigoration using incubation at controlled moisture content (30% f.w) and continuous air supply, for 14 days at 5°C.
3. Additional water supply for 16 hours at 5°C.
4. Drying in dehumidified air until a near maximum difference in density between viable and dead seeds was obtained
5. Separation in a sedimentation flume to achieve a gradient of fractions of different germination rate and capacity.
The treatments resulted in an improvement of germination percentage from 33 to about 95% and a reduction in mean germination time from 8.8 days to 6 days if the control and the best fractions (32% seeds) were compared.