S2Genetic and environmental components of variance for 2-year heights of offspring from inter- and intra-provenance matings in Scotch pine (Pinus sylvestris L.) were studied to determine which provenances and selection methods should be used in a program to improve ornamental and Christmas trees. The study represents 11 experiments (parental groups), consisting of families from 7 diallel matings minus selfs in 5 different provenances, 3 factorial matings between provenances, and 1 from open pollination. The seedlings for the 11 experiments were grown in pots and in a nursery for 2 years. Heritability estimates of 2-year height from inter- and intra-provenance matings tended to be larger on a family basis than on an individual basis, with the larger estimates being from nursery evaluations. In general, additive genetic variance was larger than dominance variance, although dominance variance increased in provenance hybrids. Nursery evaluation was preferred to pot evaluation of 2-year height because heritability estimates were larger and error variances were smaller for the experiments evaluated. Individual selection in the nursery within the German provenance seems to be the best method for improvement of 2-year height of the provenances evaluated in this study, although the rate of improvement in the Spanish provenance may be greater. Simple recurrent selection would be a good method for improvement of traits important to the Christmas tree producing industry. S3.

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