Phenotypic and Genetic Variation in the Seed Maturity of Scots Pine

Abstract

Summary Scots pine (Pinus sylvestris L.) seed matures poorly in northern areas, which causes great problems for forest regeneration. Variation in anatomical seed maturity between individuals and years was studied in 2 natural northern populations (67 °N and 68 °N), one of which was a timber line population. The amount of genetic variation in anatomical seed maturity was estimated in 2 test sites at different latitudes (62 °N and 66 °N) for 2 years. The test sites had identical genotypes cloned by grafting. The variation in the seed maturity between individuals in the timber line population was consistent over the years (correlations between years 0.61 to 0.67). Genetic variation was most clearly expressed in northern conditions (broad-sense heritability, H = 0.79, SD = 0.06; H = 0.73, SD = 0.08) where problems caused by poor seed maturity are the most severe. In the southern test site, the heritabilities were lower due to almost complete seed maturity. High broadsense heritabilities suggest that seed-maturing ability should be regarded as an important character in selecting clones for seed production in northern conditions.