Effect of Different Inbreeding Levels on Filled Seed Production in Douglas-fir

1989

S. 54-59

4 Abb., 3 Tab., 26 Lit. Ang.

Unselbständiges Werk

200038929

Matings of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) were performed to develop inbreeding levels with inbreeding coefficient (F) values from 0.0 to 0.75. A strong inverse linear relationship was found between filled seed per cone and F at values (Formel). The following mean filled seed per cone values were obtained: outcross (F=0.0), 31.6; half-sib cross (F=0.125), 21.3; full-sib cross (F=0.25), 16.7; parent-offspring backcross (F=0.25), 15.5; self (F=0.5), 1.2; second generation self (F=0.75), 0.03. Parental effects on filled seed per cone were large, accounting for about 50% of the total variation. The use of related clones in a seed orchard will result in less inbred seed than expected under total panmixia, owing to decreased filled seed production at all inbred levels. Also, breeding programs will require increased effort to obtain seed when mating designs include crosses between related trees.