Turpentine composition of Pinus contorta × Pinus banksiana hybrids and hybrid derivatives

Abstract

Inheritance of turpentine composition in Pinus contorta × pinus banksiana hybrids has been studied on the basis of 7 pure Pinus banksiana trees, 17 pure Pinus contorta trees, 18 backcrosses to P. banksiana, 32 F1, 6 F2, 41 F3, and 9 natural hybrids. Although it was impossible from the data obtained to formulate an appropriate inheritance model, the results suggested that the differences in turpentine composition are controlled primarily by a limited number of genes with major effects. The major difficulty in working out the inheritance model was the failure to recover, in the F2 and F3 generations, the original levels of β-phellandrene, the quantitatively most important terpene of P. contorta. It is suggested that this might be due to the introduction of competing enzymatic systems, which, by producing independently large amounts of pinenes, would lower the β-phellandrene level.