On-farm genetic diversity of maize: Data and defining the blanks

Abstract

Maize (Zea mays) monoculture in the U.S. is causing an environmental crisis from insecticide-treated seeds leaching into groundwater to a hypoxic zone in the Gulf of Mexico to the degradation of soils. Researchers are concerned the crisis may be even more severe – a narrowing genetic base of commercially available maize seed in the U.S. (Mikel, 2008; Van Heerwaarden et al., 2012; Smith et al., 2022). Narrowed genetic diversity on farms puts farmers and consumers at risk to crop failure. However, the data needed to conduct quantitative genetic vulnerability assessments are made confidential through intellectual property restrictions. U.S. federal intellectual property policies that have helped create the most consolidated seed industry in recent history also allow private companies to control the management of genetic resources (McCluskey & Tracy, 2021; Smith et al., 2022). This model is being exported internationally, most concerningly to the center of domestication and diversity in Mexico through the United States - Mexico - Canada free trade agreement (Hernandez-Lopez, 2020; 2022).

Given concerns about a narrowing of the genetic base and the U.S. Department of Agriculture calling for vulnerability assessments on the maize landscape, my research initially set out to describe the on-farm genetic diversity of maize in the U.S. Genetic testing is the ideal quantitative method but companies holding the patent control who are allowed to do so. We explored using market data to conduct a surface level assessment and describe the number of unique hybrids grown across the landscape. But in the U.S. one maize hybrid can be sold under different variety names by companies who license genetics to one another (McCluskey & Tracy, 2021). This proved the market data unusable. We explored a quantitative survey of farmers about what hybrids they grow on their hectares, but farmers do not have access to the genetic background of their maize seed (McCluskey & Tracy, 2021) and we determined this method was unlikely to produce the richness of genetic background data needed. We were awash in “blanks” and concluded that intellectual property used on maize seed in the U.S. obfuscates our ability to measure on-farm genetic diversity.

Instead we developed a qualitative study to describe the contours of these “blanks.” We conducted semi-structured interviews with maize genetic diversity experts in both the public and private sectors (n=45) about their perceptions and analysis of on-farm genetic diversity. Our analysis provides insights into the genetic base of U.S. maize and how intellectual property restrictions on seed create “blanks” about resources that humankind relies on for survival.