A diallel cross in Sitka spruce assessment of first year characters in an early glasshouse test.

The successful pollination of a complete diallel cross among six Sitka spruce (Picea sitchensis (Bong.) Carr.) trees is described, together with the assessment of a range of characters in the first growing-season of an early progeny-test in a glasshouse. Those characters chiefly concerned with tree form were found to be inherited in a predominantly additive fashion, whilst those characters reflecting various aspects of tree vigour were found to be under additive, dominance and maternal control. The results are discussed in the light of selection criteria and current techniques in Sitka spruce breeding.