Geographic variation in growth, carbon isotope discrimination, and monoterpene composition in Pinus pinaster Ait. provenances

The geographic variation in monoterpene composition, growth, and carbon isotope discrimination (Δ) was assessed for trees of maritime pine, Pinus pinaster Ait., from five provenances (one Portuguese, Corsican, and Tuscan and two Sardinian: Telti and Limbara) grown on four different field sites in Sardinia island, Italy. Analysis of monoterpenes as biochemical markers revealed differentiation among the provenances and suggest four groupings, corresponding to the pooled Sardinian provenances (Telti and Limbara) and the other individually separated provenances. The five provenances exhibited statistically significant variation for height and diameter. Significant variation for growth parameters were also observed among the locations studied. The five provenances showed weak variations for Δ (range 17.1-17.5‰), while highly significant differences were observed amongst the four sites. A strong negative correlation was observed between mean tree height and mean Δ for the five provenances only at one site (the coolest and highest); the relationship was weak for the five seed sources at the other three locations. The Portuguese provenance that showed the highest potential for growth amongst the seed sources studied had a distinct terpene pattern and a tendency for lower Δ (higher WUE) than the other populations.