Modification of genotypes: genetic engineering and genetically modified trees

The improvement of genetic quality starts with the natural variability provided by species, provenances, and individuals. This is then used as a basis for breeding to actively combine and improve desirable traits. Subsequent generations of breeding bring further improvement. Such improvement has been practiced for centuries in agriculture, but is more recent in forestry. All such selection and breeding involves using the natural variability of genes on chromosomes that are found in genotypes / genomes. Genetic engineering takes a step further, in that the chromosomes and their genes are added, moved or modified. Modification may entail transferring genes from one individual, or one species, to another, by physical or chemical means, The result is a genetically modified or transgenic tree (known generically as a genetically modified organism (GMO)). Genetic engineering is just one advanced technique of biotechnology, a term that can encompass traditional plant breeding, but tends to be used for a range of new micro-techniques which range from quantifying genetic diversity (using molecular markers), or improving vegetative propagation in order to support breeding and multiplication, through to genetic engineering. Note that one use of the term bio-engineering is different - seeRegenaration in the field).

For more information see the following Web pages:

Genetic engineering is being used extensively in some important crops in agriculture. It is causing concern because of the potential unknown effects of interfering with the genes. These effects can be either to the organism itself as it develops and reproduces; or to other organisms where cross breeding of the modified organism occurs (such as through natural pollination), or (possibly) to the people if they use or consume the organism. FAO notes that genetic modification is not a good in itself, but a tool which must be integrated into a wider research agenda. Developing transgenic crops implies massive investments, and the need for massive returns; strategies for improvement and breeding must be balanced to meet objectives in a balanced and optimized manner.

For general information on GMOs in agriculture, see the following articles on the FAO Web site on genetically modifed crops and their future: Genetically modified crops athttp://www.fao.org/ag/magazine/0111sp.htmand Genetically Modified Organisms in Food and Agriculture: Where are we? Where are we going? athttp://www.fao.org/ag/magazine/GMOs.pdf.

In forestry, genetic modification is being tested using techniques such as recombinant DNA and asexual gene transfer, to introduce herbicide and pest resistance, or to reduce or modify the lignin content of wood. Experiments have been carried out on several species, but are most advanced for poplar, pine and eucalyptus. No commercial plantations of GM trees have yet been established.

The problems associated with GM trees are potentially more serious than for agricultural crops. There are several reasons for this, one being that because trees are relatively undomesticated, and have a long life cycle, there is an increased risk of contaminating natural populations. However, the characteristics most likely to be selected for are simply-inherited traits found within the natural variation of the species, which should reduce potential problems. One way that may avoid these problems is to engineer the tree so that it is sterile.

GMOs are a concern for some institutions wishing to grow and certify organically or sustainably managed products. The Forestry Stewardship Council (seeRegulating and applying standards) will not certify genetically modified plantations, because of the unknown effects and potential costs which could not be certified as "sustainable". However, some certifying schemes do allow use of GM trees.

Problems of invasiveness, introduction of pests and diseases, and uncontrolled changes following genetic engineering etc, all carry enviromental, social and economic risk of adverse effects on people. The measures taken to manage these risks via policy, law, technology etc. are now collectively referred to by the term bioprotection, which encompasses terms previously used of biosecurity and biosafety.

last updated:  Wednesday, April 18, 2007