Genetically Engineered Plants:
a Threat to Centres of Diversity

Greenpeace International, September 1999

Centres of diversity are places where the special interrelation between our crop plants and their wild relatives is still apparent. In such places, tens of thousands of varieties of rice, potato, maize, or other food staples are still grown and used by local people. Centres of diversity are the basis not only for food security, but also for cultural traditions.

The introduction of genetically engineered (GE) plants into agriculture poses a serious threat to our centres of diversity. In particular wild plants and local crop varieties risk acquiring the GE traits, giving rise to strains of plants with a fitness advantage over their neighbours. This could severely disrupt local ecosystems. Any release of GE plants in centres of diversity - either through seed or commodity import - poses a serious threat to our biological heritage, cultural roots, and global food security.

A centre of diversity refers both to the region in which a crop originates - and where we find the widest range of related species - and to the region of early breeding and improvement of a crop into specific varieties. It is a generic term, encompassing the diversity both of specific crop varieties and of wild relatives and related species.

Centres of diversity - a basis for food security and cultural values

Diversity represents the world's biological and cultural heritage. It is also the biological mechanism that allows us to cope with changing environmental conditions, ensuring food security in the long term. In order to overcome new epidemics of pests and diseases or to adapt a crop to changing climatic conditions, farmers and plant breeders need a broad genetic base of their crop plants. This may include varieties that are not necessarily commercially interesting or high yielding, yet confer resistance to biological stress in less than ideal conditions.

Genetically engineered plants - a new threat to centres of diversity

The Green Revolution with its uniform hybrid varieties and the associated social and economic changes has been a major cause of the decline of crop diversity. The introduction of GE plants intensifies this move toward crop uniformity. But GE crops are more than just the next generation of high-tech varieties. They feature two specific characteristics that could make them a special threat to centres of diversity, where the newly introduced genes may find the best opportunity to escape and where vital resources are at stake:

• Firstly, GE plants contain genes and traits that are completely new to the target species, its environmental context, and its genetic background. While traditional breeding can move genes only among related varieties or closely related species, genetic engineering allows for a movement of genes across radically different species. No traditional breeder is able to cross a carp with a potato, or a bacterium with a maize plant. There is no history of bacterial genes in maize. There was no evolution or selection over thousands of years that would have qualified the bacterial gene to be an integrated part of the maize population. The effect of newly introduced genes and gene fragments under real world conditions, in different climates or in reaction to different pests or diseases, is completely unpredictable, posing a threat not only to the crop, but also to related species and the ecosystem.
  
  
• Secondly, the process of genetic engineering is neither targeted nor precise but a rather crude intervention or bombardment. The newly introduced gene could end up being integrated anywhere in the plant genome. It can neither be directed to a specific site within the plant's genes, nor is the site of integration necessarily known afterwards. Because the expression of a given gene or gene fragment depends heavily on the site of integration and the genetic background, it is merely a matter of luck if the newly introduced gene works as expected and no major changes in the plant performance are induced. Several natural mechanisms are known (e.g. pleiotropy, epistasis, or position effects) to influence the specific outcome of a foreign gene transfer and these cannot be anticipated.

The risk of gene flow is greatest in the centres of diversity

Once released into the environment, GE plants cannot be contained or confined. Like all living organisms, GE plants reproduce and this is an opportunity for gene flow beyond the designated area of growth. Seeds can be picked up by birds and dropped elsewhere, potato tubers can be removed by bigger mammals, or reproducible plant parts could just be dislocated by wind. The major escape path for the newly introduced gene into the wild is via pollen transfer.

When a GE plant flowers, the pollen contains the newly introduced genetic material and can carry it to another plant, fertilise it, resulting in seeds that will also contain the engineered gene. The only precondition for this kind of gene flow is the presence of compatible plants in the vicinity. This is almost inevitable in a plant's centre of diversity where a GE crop will be surrounded by compatible plants - be they local varieties and landraces of the crop or wild species - and will facilitate the transfer of the new gene into local populations.

Genetically engineered plants' impact on local varieties and natural ecosystems

One major fear is the possibility that the newly introduced gene will confer a selective advantage and will thus enable the plant to out-compete and overrun other natural vegetation. The risk is greatest when a wild relative of a GE plant is already considered a weed. Should this weed acquire - via pollen transfer - new genetic material conferring a selective advantage, it might wreak havoc in both agriculture and natural habitats.

Greenpeace demands

Greenpeace believes that any irreversible release of genetically modified organisms (known as GMOs) into the environment is irresponsible given the present state of knowledge about their possible adverse effects on the environment and human health. There is already sufficient evidence that the release of GMOs can have irreversible effects and that their genetic pollution may lead to self-replicating and man-made destruction of the environment.

Living entities like maize kernels, potatoes, tomatoes, or cereal grains can generate new plants. Even if the intended use is processing for food or feed, there is always the risk of spill-over or use for replanting.

• Any country with a centre of diversity for one or more crop plants under its jurisdiction should take specific legislative measures to forbid the introduction and cultivation of GE varieties of these crops. As small-scale field trials also present the risk of outcrossing, these should be banned as well.
  
  
• Prior consultation with neighbouring states should be mandatory before any country can decide to grow GE crops. Measures must also be taken to prevent illegal international movement of GE crops to centres of diversity.
  
  
• Urgent national and international measures are required to stop genetic erosion and to protect the global heritage of the world's crop diversity in their regional environment and cultural context.

Download the full report "Centres of Diversity - Global Heritage of Crop Varieties Threatened by Genetic Pollution" (Adobe Acrobat format)

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