ASYMPTOTIC RATES OF RESPONSE FROM FOREST TREE BREEDING STRATEGIES USING BEST LINEAR UNBIASED PREDICTION

Genetic gain equations are developed for selection on multiple traits using either multi- or univariate best linear unbiased predictors (BLU P) and for selection under controlled and open pollination and polymix mating schemes, The equations assume an infinite population and accou nt for the effects of selection. A comparison with simulated populatio ns under the same mating schemes show that the rr;ain equations predic t selection response well, with the predictions having some upward bia s. The gain equations are used to compare across mating schemes, to co mpare univariate to multivariate analyses, and to measure the reductio n in the rate of genetic gain due to selection disequilibrium. Results show controlled pollination schemes can offer as much as a 56% advant age in genetic gain relative to open pollination. The reduction in the rate of genetic gain due to selection disequilibrium is approximately 27% under controlled pollination for the breeding goals studied. The results show a limited benefit in using multivariate analyses for pred icting breeding values.