Genotypic parameters and clone x site interaction in clone tests of Norway spruce (Picea abies (L.) Karst.)

Abstract

Genotypic parameters for growth and qualitative traits were estimated in an 1 I -year-old series of five field tests containing 3 1 1 cutting propagated clones selected from 5 diSSerent provenance groups. Significant differences among provenance groups and rather high broad sense heritabilities ( H z = 0.08 -0.34) for clones were found for growth traits. For most qualitative traits no significant differences were found between provenance groups, while heritabilities for such traits varied more than for growth traits. Significant clone x site interaction components of variation were found for most traits. Bud flush was the most stable trait over sites with a low interaction component of variance compared with the clone variance. Since height increment during the last 5 years showed higher interaction with site than total height, it is concluded that clone x site interaction may be increasing with agc in Norway spruce and ought to be studied more carefully. Despite the significant interaction, the results are not considcrcd to be a problem for efficient use of genetically improved material of Norway spruce in Sweden since the legislation requires rather large numbers of genetic entries for reforestation.