Coexistence and ecological biosafety of two GM crops in Europe

The three-year, EU-funded project SIGMEA combined skills from many disciplines to examine the biological, environmental, agronomic, economic and legal issues that determine whether GM and non-GM crops can feasibly be grown in the same agricultural landscape. Its conclusions differed for the two crops that have been most widely studied.

Map of field patterning in a study of cross pollination - provided by Enric Mele, SpainSIGMEA reported mainly on coexistence, but also on ecological biosafety. Coexistence refers to the need to separate, in the food production chain, different types of crop, such as those that have been developed with or without genetic modification. While zero impurity of one type of crop in another is impossible to guarantee, the EU had set a threshold of 0.9% GM content for produce that can be labelled as GM-free.

Coexistence should be considered both in time (non-GM crop grown after a GM crop in the same field) and in space, where the two types are grown in different fields in the same landscape. Ecological biosafety is about whether the GM crop and its management will harm non-target or beneficial organisms, food webs and ecological processes.

Photograph of wild beet plant on the Adriatic coast – provided by Piergiorgio Stevanato, ItalySCRI’s role was to coordinate about half the project (known as Workpackage 2 or WP2) – which brought together, audited and analysed all data in Europe from field experiments on gene movement and ecological biosafety, particularly for those two crops that had been examined extensively in the field – GM insect resistant maize (Bt, Lepidoptera) and herbicide-tolerant oilseed rape. It also examined in detail the interactions within the Beta complex, consisting of crop beets and their wild, feral, and weedy relatives.

Conclusions on coexistence and biosafety

The full, final reports on WP2 come to over 200 pages. Links to summary documents for the whole project and WP2 are given below on this page. The data and analyses led to the following main conclusions.

Insect-resistant Bt maize (resistance against Lepidopteran pests such as corn borer)

  • Photograph of maize cobs in a field sown with a landrace – provided by Roberto Papa, Italy Coexistence at a 0.9% labelling threshold should be feasible ‘in time’ and ‘in space’ given flexible measures to achieve separation of fields.
  • No consistent or systematic, negative effects on non-target organisms and other indicators compared to non-GM crop management were found in field trials (some over nine years).
  • There are advantages of growing Bt maize in those parts of Europe where corn borers are a problem pest.

Herbicide tolerant (HT) oilseed rape

  • Photograph of flowering volunteer oilseed rape in a cereal field – provided by Rikke Bagger Jorgensen, Denmark.Coexistence ‘in space’ will be possible at first after commercialisation, but would be difficult to achieve in the longer term because seed-borne impurities will become widely distributed. Coexistence ‘in time’ would be very difficult to achieve under most circumstances.
  • The type of weed management associated with GM HT oilseed rape would likely reduce already depleted food webs, while GM herbicide tolerant volunteers would increase problems of weed management in some subsequent crops.
  • There are few advantages of GM HT oilseed rape in Europe, and none that would generally outweigh these negative effects.

More generally, SIGMEA concluded that the outcome of an assessment of a GM crop depends not only on the GM trait, but on the characteristics of the crop-species, the associated management of the crop and environment in which it is grown. Each assessment is therefore unique. Generalisations for all GM crops – for example, on whether they are positive or negative for the economy or the environment - have no scientific basis.

Information, contacts and references

For an expanded text on the conclusions of WP2 for coexistence:

For SCRI’s contributions see the SIGMEA page.

For final reports on all SIGMEA workpackages (to be updated): SIGMEA website.

For a summary of the whole SIGMEA project:

Messean, A., Squire, G., Perry, J., Angevin, F., Gomez, M., Townend, P., Sausse, C., Breckling, B., Langrell, S., Dzeroski, S., Sweet, J. 2009. Sustainable introduction of GM crops into european agriculture: a summary report of the FP6 SIGMEA research project. OCL 16(1), 37-51. (doi:10.1684/ocl.2009.0241.) PDF file of this article (1089kb).

People at SCRI: Geoff Squire (coordinator). Staff: Mark Young (data manager), Gill Banks, Lawrie Brown, Linda Ford. Expertise: Pete Iannetta (detection, persistence), Graham Begg (modelling), Gavin Ramsay (genetics, cross pollination), Cathy Hawes (food webs, impacts).

(Added 27 May 2009; reference added 10 August 2009)