Sammendrag
Genetic variation and phenotypic stability in Norway spruce were studied based on
provenances, families, and clones planted in trials at 12 sites in four Nordic countries. The families
were generated in a factorial cross between 10 parents of Norwegian origin and 10 parents of Eastern
European origin, and the clones were propagated from seedlings within 20 of the same families. Traits
analyzed were survival, proportion of trees with stem defects, and tree heights. Stability was analyzed
by regression analyses with the genetic entries’ annual shoot increment as the dependent variable
and the total site mean as an environmental index. Information about growth and phenology traits
were available from short-term tests. For tree heights, significant variance components were present
both among female and male parents, but not for their interactions, indicating that non-additive
genetic effects are small. Genotype × environment interactions were significant at all three genetic
levels, but their variance components had considerably lower values than the variance components
estimated for the effects of families and clones. For the set of families of Norwegian origin, strong
relationships were observed between the timing of annual shot elongation, mortality, and height
growth. Large variation was found at all three genetic levels for phenotypic stability measured by
regression coefficients. A positive relationship was present between the regression coefficient and the
timing of annual shoot growth for families, indicating that later flushing families responded more to
a high site index. The regression coefficient can be a useful supplement to the breeding value when
selecting for superior and stable genotypes.
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