• Open Access

Pollen-mediated gene flow in maize in real situations of coexistence

Authors

  • Joaquima Messeguer,

    Corresponding author
    1. Consorci Laboratori CSIC-IRTA de Genètica Molecular Vegetal, Departament de Genètica Vegetal, Centre de Cabrils, Carretera de Cabrils s/n, Cabrils 08348 (Barcelona), Spain
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  • Gisela Peñas,

    1. Consorci Laboratori CSIC-IRTA de Genètica Molecular Vegetal, Departament de Genètica Vegetal, Centre de Cabrils, Carretera de Cabrils s/n, Cabrils 08348 (Barcelona), Spain
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  • Jordi Ballester,

    1. Applus + Agroalimentario Análisis Genéticos, Ctra. d’Accés a la Facultat de Medicina s/n, Campus UAB, Bellaterra 08193 (Barcelona), Spain
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  • Marta Bas,

    1. Applus + Agroalimentario Análisis Genéticos, Ctra. d’Accés a la Facultat de Medicina s/n, Campus UAB, Bellaterra 08193 (Barcelona), Spain
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  • Joan Serra,

    1. IRTA-Estació Experimental Agrícola Mas Badia, Mas Badia la Tallada d’Empordà, 17134 (Girona), Spain
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  • Jordi Salvia,

    1. IRTA-Estació Experimental Agrícola Mas Badia, Mas Badia la Tallada d’Empordà, 17134 (Girona), Spain
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  • Montserrat Palaudelmàs,

    1. Consorci Laboratori CSIC-IRTA de Genètica Molecular Vegetal, Departament de Genètica Vegetal, Centre de Cabrils, Carretera de Cabrils s/n, Cabrils 08348 (Barcelona), Spain
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  • Enric Melé

    1. Consorci Laboratori CSIC-IRTA de Genètica Molecular Vegetal, Departament de Genètica Vegetal, Centre de Cabrils, Carretera de Cabrils s/n, Cabrils 08348 (Barcelona), Spain
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* Correspondence (fax 34 93 753 39 54; e-mail joaquima.messeguer@irta.es)

Summary

We present the first study on cross-fertilization between Bt and conventional maize in real situations of coexistence in two regions in which Bt and conventional maize were cultivated. A map was designed and the different crops were identified, as were the sowing and flowering dates, in Bt and conventional maize fields. These data were used to choose the non-transgenic fields for sampling and analysis by the real-time quantification system-polymerase chain reaction (RTQ-PCR) technique. In general, the rate of cross-fertilization was higher in the borders and, in most of the fields, decreased towards the centre of the field. Nine fields had values of genetically modified organism DNA to total DNA of much lower than 0.9%, whereas in three the rate was higher. Some differences were found when comparing our results with those of common field trials. In real conditions of coexistence and in cropping areas with smaller fields, the main factors that determined cross-pollination were the synchronicity of flowering and the distances between the donor and receptor fields. By establishing an index based on these two variables, the rate of the adventitious presence of genetically modified maize could be predicted, as well as the influence of other factors. By applying this index, and in the case of a fully synchronous flowering time, a security distance between transgenic and conventional fields of about 20 m should be sufficient to maintain the adventitious presence of genetically modified organisms as a result of pollen flow below the 0.9% threshold in the total yield of the field.

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