Genetic parameters and clone by environment interactions for growth and foliar nutrient concentrations in radiata pine on 14 widely diverse New Zealand sites

Abstract

Genetic variations and genotype by environment (G × E) interactions in growth and foliar traits were studied with 40 clones of radiata pine in a trial series on 14 sites across a range of environments in New Zealand. Total height was assessed at ages 1, 3, 5, 6 and 8 years from planting. Stem diameter was assessed as ground-level diameter at ages 1 and 3 years and diameter at breast height (DBH) at ages 5, 6 and 8 years. Fascicle weight, foliar nutrient concentrations, foliar carbon isotope composition and nitrogen isotope composition were assessed at age 5 years at seven sites. Significant genetic variation in these traits existed at most of the sites but with variable and incomplete consistency from site to site, indicating G × E interactions. Individual-tree clonal repeatability (cf. broad-sense heritability) of total height and stem diameter tended to increase with age. Furthermore, across-sites estimates of clonal repeatability of total height and stem diameter were lower than single-site estimates. Marked G × E interactions were observed in growth and foliar traits. The interaction levels for growth traits were significantly associated with site differences in soil nutrient levels of nitrogen and total phosphorus and annual mean temperature. The G × E interaction levels for two foliar traits calcium content and fascicle weight were significantly associated with the site difference of soil nutrient levels of magnesium and potassium, respectively. Foliar carbon isotope composition and carbon/nitrogen ratio showed moderate clonal repeatability and high genetic correlations with growth, suggesting that they could be used as selection traits for improving radiata pine growth rate.