To the Editor:

A letter of correspondence by Dany Morisset and his colleagues1 in the August 2009 issue cites two recent publications2,3 in which “two commercial seed varieties of the MON810 maize genetically modified event (ARISTIS BT and CGS4540) present genetic variation thus hampering the detection by several methods for MON810 (Monsanto, St. Louis).” As representatives of Monsanto Europe (Brussels), Syngenta Crop Protection (Basel) and Limagrain Services Holding (Chappes, France), we would like to correct the scientific record concerning the claimed “variation” of the transgenic insertion in these transgenic hybrids.

Upon request for further information, Margarita Aguilera and her colleagues at the European Commission, Directorate General Joint Research Center (JRC) in Ispra, Italy, informed us that the seeds tested were among 26 MON810 varieties provided by the Spanish Instituto Nacional de Investigación y Technología Agraria y Alimentaria (INIA; Madrid). The Spanish agency did not provide the JRC with details of the respective batch numbers for each variety.

Our investigation has revealed that the two deviating results were not in fact related to variation of the transgenic insertion, as reported by Aguilera et al.2,3. Instead, our conclusions are that the two varieties (reported as entry 2 and entry 5) were not MON810 maize hybrids at all.

Variety CGS4540 (entry 5) is a Bt176 maize hybrid and we do not understand why the seed was provided by INIA as MON810. Entry 2, which was designated as Aristis Bt, is most likely Aristis, the conventional counterpart of Aristis Bt (MON810). When we requested INIA to send a sample of Aristis Bt to its official Spanish laboratory CSIC (Consejo Superior de Investigaciones Científicas) for testing, the results were positive for MON810, as expected.

Aguilera and her colleagues were not able to provide a correct chain of custody for the samples used in their analyses, which would have allowed resolution of the origin of these deviating results.

The seed industry has invested significantly to provide quality products to the market place, which includes selling compliant and stable products. Traits are tested for presence and stability for many generations before release to the market place. We are therefore convinced that there is no scientific evidence of instability in MON810 hybrids.