J Van Doorsselaere, H Beeckman, M Van Montagu, W Boerjan
The genetic improvement of forest trees by classical breeding is a slow process in comparison with that of annual crops. Tree breeding however is of great importance and has led to trees with better growth characteristics and better disease resistance. An important wood characteristic which has been neglected in breeding programs is wood durability. The durability of the wood will determine for which purpose the wood can be used and this is of great economic value. Genetic engineering can accelerate tree improvement significantly. It allows the modification or addition of a given trait in any tree species. Here, some examples of genetic engineering in trees (mainly poplar species) are given. For instance, transgenic poplar trees that have a modified lignin biosynthesis to improve pulping, are examined in more detail. Furthermore, the possibilities to enhance wood durability by genetic engineering are discussed.