Cross-fertilization between genetically modified and non-genetically modified maize crops in Uruguay

Abstract

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.

Geostatistical Analysis of Quality Protein Maize Outcrossing with Pollen from Adjacent Normal Endosperm Maize Varieties

“…The variation in outcrossing from site to site and season to season, prevailing wind direction effects, and effects of synchrony of flowering and distance from the yellow source were previously reported by Haegele and Peterson (2007), Langhof et al (2010b), and Viljoen and Chetty (2011). In general and as expected, the level of outcrossing decreased as the distance from the NM pollen source increased and this trend is consistent with earlier studies by Bateman (1947), Paterniani and Stort (1974), Garcia et al (1998), Sears and Stanley‐Horn (2000), Luna et al (2001), Burris (2001), Halsey et al (2005), Brookes et al (2004), Haegele and Peterson (2007), Popescu et al (2010), Langhof et al (2010b), Galeano et al (2011), and Viljoen and Chetty (2011).…”

Scientific Opinion updating the risk assessment conclusions and risk management recommendations on the genetically modified insect resistant maize MON 810

“…- Galeano et al (2011) investigated the level of cross-pollination between Bt-maize (Cry1Abexpressing maize events MON 810 and Bt11) and conventional maize in Uruguay. The authors followed five pairs of fields in their study, each of which consisted of a GM maize field located nearby a field cropped to non-GM maize.…”

Los cultivos transgénicos y los paradigmas científicos de los que emergen a la luz de los derechos de la naturaleza

“…[19] Contaminación genética de parientes silvestres y variedades tradicionales de maíz ha sido reportado desde 2001 en México (Chapela y Quist, 2001), Perú (Gutiérrez, 2007), Uruguay (Galeano et al, 2010).…”