NOTE: Here is the abstract of a paper on the GM contamination of non-GM maize. The paper by Pablo Galeano et al was recently published in the peer reviewed journal of Environmental Biosafety Research. It's a technical paper with a clear conclusion, coexistence is going to be very difficult to achieve.

This is in line with the conclusion of research published in the Journal of Agricultural and Environmental Ethics: "An impossible coexistence: transgenic and organic agriculture", which noted that, "The cultivation of genetically modified maize [in Spain] has caused a drastic reduction in organic cultivations of this grain and is making their coexistence practically impossible."  
Case study: Cross-fertilization between genetically modified and non-genetically modified maize crops in Uruguay

Environ. Biosafety Res. Available online at:
ISBR, EDP Sciences, 2011
DOI: 10.1051/ebr/2011100

Authors: Pablo Galeano 1,2*, Claudio Martinez Debat 3, Fabiana Ruibal 3, Laura Franco Fraguas 2 and Guillermo A. Galvan 1

1 Departamento de Produccion Vegetal, Centro Regional Sur (CRS), Facultad de Agronomía, Universidad de la Republica, Camino Folle
km 36, Progreso, Canelones, Uruguay

2 Catedra de Bioquimica, Departamento de Biociencias, Facultad de Quimica, Universidad de la República, General Flores 2124,
Montevideo, Uruguay

3 Seccion Bioquimica, Instituto de Biología, Facultad de Ciencias, Universidad de la Republica, Igua 4225, Montevideo, Uruguay


The cultivation of genetically modified (GM) Bt maize (Zea mays L.) events MON810 and Bt11 is permitted in Uruguay. Local regulations specify that 10% of the crop should be a non-GM cultivar as refuge area for biodiversity, and the distance from other non-GM maize crops should be more than 250 m in order to avoid crosspollination. However, the degree of cross-fertilization between maize crops in Uruguay is unknown.

The level of adventitious presence of GM material in non-GM crops is a relevant issue for organic farming, in situ conservation of genetic resources and seed production. In the research reported here, the occurrence and frequency of cross-fertilization between commercial GM and non-GM maize crops in Uruguay was assessed.

The methodology comprised field sampling and detection using DAS-ELISA and PCR. Five field-pair cases where GM maize crops were grown near non-GM maize crops were identified. These cases had the potential to cross-fertilize considering the distance between crops and the similarity of the sowing dates.

Adventitious presence of GM material in the offspring of non-GM crops was found in three of the five cases. Adventitious presence of event MON810 or Bt11 in non-GM maize, which were distinguished using specific primers, matched the events in the putative sources of transgenic pollen.

Percentages of transgenic seedlings in the offspring of the non-GM crops were estimated as 0.56%, 0.83% and 0.13% for three sampling sites with distances of respectively 40, 100 and 330 m from the GM crops.

This is a first indication that adventitious presence of transgenes in non-GM maize crops will occur in Uruguay if isolation by distance and/or time is not provided. These findings contribute to the evaluation of the applicability of the "regulated coexistence policy" in Uruguay.

(Received September 23 2010)

(Accepted January 11 2011)

(Online publication March 25 2011)

Key Words:
* Bt;
* Bt11;
* gene-flow;
* MON810;
* out-crossing;
* Zea mays


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