Genotype by Environment Interaction and Genetic Correlation of Greenhouse and Field Performance in Pinus contorta ssp. latifolia

Summary Family by site interaction from 4 progeny test sites for 9year height and its impact on estimation of genetic correlation between greenhouse traits and 9-year height were investigated in 110 families of Pinus contorta ssp. latifolia from Alberta, Canada. Significant family by site interaction, site and family effects were observed in 9-year height among 4 progeny test sites. The estimated narrow-sense heritability was from 0.127 to 0.277 for individuals and was from 0.247 to 0.475 for family means. 25 greenhouse seedling traits (height, diameter, bud, branch and biomass) in 2 growing seasons were jointly studied with 9-year tree height at the 4 progeny test sites. The genotype by site interaction had a significant impact on greenhouse-field family-means and genetic correlations. Only 9-year tree height in the best site (site B), which had more similar growing conditions to the greenhouse, had significant familymean and genetic correlations with greenhouse seedling traits. Seedling traits of height increment at the dormancy induction period between 2 growing seasons (HG1, r g = 0.52), height at the second growing season (H3, r g = 0.36), and height (r g = 0.37) and diameter (r g = 0.42) at harvest, had the highest and significant family-mean and genetic correlation. The pattern of greenhouse-field family-mean and genetic correlations among 4 sites indicates that early testing should be conducted under simulated field conditions. The implications of genotype by site interaction on early selection were discussed for lodgepole pine.