Skip to main content
ARS Home » Southeast Area » Stoneville, Mississippi » Southern Insect Management Research » Research » Publications at this Location » Publication #401096
Research Project: Insect Control and Resistance Management in Corn, Cotton, Sorghum, Soybean, and Sweet Potato, and Alternative Approaches to Tarnished Plant Bug Control in the Southern United States

Location: Southern Insect Management Research

Title: Functional transgenes in Mexican maize: benefit and risks for insect pest management in Mexico and the United States

Author
item BLANCO, CARLOS - University Of New Mexico
item HERNANDEZ, GERARDO - Guanajuato Campus Of Cinvestav
item CONOVER, KEVIN - University Of Maryland
item Portilla, Maribel
item VALENTINI, GISELI - US Department Of Agriculture (USDA)
item ALVARADO, ALEJANDRA - Universidad Nacional Autonoma De Mexico
item FOSADO, ANTONIO - Universidad Nacional Autonoma De Mexico
item Abel, Craig
item DIVELY, GALEN - University Of Maryland
item GUZMAN, HOMERO - US Department Of Agriculture (USDA)
item ISRAEL, LORENZO-FELIP - Secretariat Of Agriculture And Rural Development
item OCCELLI, LAURA - US Department Of Agriculture (USDA)
item KNOLHOFF, LISA - US Department Of Agriculture (USDA)
item CORONA, MIGUEL - US Department Of Agriculture (USDA)
item VEGA, PAULINA - Dupont Pioneer Hi-Bred
item MACIAS, PEDRO - Secretariat Of Agriculture And Rural Development
item WARD, TINE - US Department Of Agriculture (USDA)
item URBANO, NAVA - Juarez University Of The State Of Durango

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/22/2024
Publication Date: 4/9/2024
Citation: Blanco, C., Hernandez, G., Conover, K., Portilla, M., Valentini, G., Alvarado, A., Fosado, A., Abel, C.A., Dively, G., Guzman, H., Israel, L., Occelli, L., Knolhoff, L., Corona, M., Vega, P., Macias, P., Ward, T., Urbano, N. 2024. Functional transgenes in Mexican maize: benefit and risks for insect pest management in Mexico and the United States. Annals of the Entomological Society of America. https://doi.org/10.1093/aesa/saae007.

Interpretive Summary: The expression of herbicide-tolerant and insect-resistant transgenes has been detected in more than a third of Mexican maize landraces. These genes are likely to have been introgressed by planting maize imported from the United States. This fortuitous phenomenon, in the case of insect-resistant transgenes, may help to preserve and increase the productivity of these landraces. The inheritance of transgenes in four consecutive selfed generations did not reach stability, nor showed a Mendelian pattern of inheritance. This is an unexpected way that shows how transgenes may be introgressed and fixed in consecutive generations.

Technical Abstract: The 25-year moratorium on cultivating genetically engineered (GE) maize in Mexico has proven ineffective. During this period of prohibition, the country has imported 30-40% of its internally used maize from the United States, which contains transgenes, notably herbicide-tolerant, and insect-resistant genes. The imported maize has been grown in several parts of Mexico and we found that 35% of the locally obtained open pollinated varieties (OPVs) or landraces expressed a gene that makes this crop tolerant to glyphosate, and 31% tolerant to glufosinate, and some of the OPVs also express insecticidal genes from Bacillus thuringiensis (Bt), protecting them from a variety of pests, or the three of them. We experimented sowing the offspring of GE maize, the surrogate of U.S. exported seed, allowing it to self-pollinate in field plots, repeating this procedure for four consecutive generations. Herbicide-tolerant and Bt genes were carried into the next generations in higher-than-expected proportions, not following Mendelian pattern of segregation, or gene frequency stability generation after generation, despite the absence of herbicide and insecticide selection, or pest pressure in the field. This inheritance pattern indicate that these genes get firmly established in maize populations and have introgressed into commercial Mexican maize for more than two decades without adverse consequences. The untenable ban of the cultivation of GE maize in Mexico is further challenged due to the lack of evidence that the crop’s genetic diversity has decreased, or of any adverse effects of the commodity’s production, or its impact on the environment. This assessment shows that nearly a fifth of maize production in Mexico contain transgenes, because half of the production derives from planting hybrid maize, commercial cultivars that do not contain herbicide-tolerant transgenes.