Basic density of radiata pine in New Zealand: genetic and environmental factors

Wood basic density is among the selection criteria for many fast-grown tree species, including Pinus radiata D. Don in New Zealand. Basic density was assessed in 23,330 stem cores from 18 trials to study the heritability, the relevance of environmental effects and the magnitude of genotype-by-environment (GxE) interaction. Site differences in annual average temperature dominated variability in this dataset, with lower latitude and altitude (i.e. warmer) sites displaying higher average density. Between highest- and lowestdensity sites there was an 18% difference (302.7 vs. 358.4 kg m-3) for the linear mean for cores of rings 1–5 and a 39% difference (329.7 vs. 459.1 kg m-3) for the linear mean of rings 6–10. The estimated heritabilities fluctuated between 0.28 and 0.94 (mean, 0.6); however, basic density displayed little within-site variability (phenotypic coefficient of variation,