Performance of Pinus pinaster provenances in Spain Interpretation of the genotype by environment interaction

The objective of this study was the interpretation of the genotype-environment interaction of 46 maritime pine (Pinus pinaster Ait.) provenances tested at five sites in central Spain. Statistical relationship of the interactions of survival, volume, and polycyclism with several climatic features from the places of origin and the trial sites were analyzed. Factorial regression models and (or) biadditive or multiplicative models were used. Simple factorial regression models were adequate to explain the interaction of the two yield-related variates. Precipitation at places of seed origin and altitude of trial locations as covariates were sufficient to explain the interaction of survival. Altitude of the site of origin and the estimate of the location main effect were sufficient to explain the interaction of wood volume. No simple factorial regression model could be found for polycyclism, a trait related to the form of the tree and wood quality. The interaction was complex enough to require a biadditive model with two terms. The agreement between the estimated value for each trait and their rank according to the means at each location is good enough to allow the selection of provenances based on these models. Breeding for specific adaptation should bring substantial genetic gains.