13 - Will gene-edited and other GM crops fail sustainable food systems?

Abstract

The role of genetically modified (GM) crops in supporting sustainable food systems is an ongoing controversy. Underlying this controversy, I will argue, are radically different definitions of agricultural sustainability. One is a narrow definition, based on amelioration of current unsustainable practices, such as the use of synthetic pesticides in agriculture. The other is a broad definition, based on the long-term promotion of human and ecosystem health. To assess the sustainability impacts of GM crops, this review first provides (1) a brief summary of the sustainability impacts of herbicide-tolerant and Bacillus thuringiensis pesticidal GM crops and (2) an overview of GM plant breeding, with a focus on the problem of unintended traits (UTs) in commercial GM crops. These UTs, I argue, are a major yet underappreciated contributor to their lack of sustainability. The review asks next whether new and complex GM traits such as biofortification, or the subset of new GM techniques called gene editing, can benefit sustainable agriculture. Golden Rice provides a case study of UTs in GM crops carrying complex traits. Given the failings of Golden Rice, caused in part by UTs, a key question is whether gene editing techniques are more precise and their outcomes more predictable. To address this, the review summarizes the known unintended effects of gene editing and their potential for introducing UTs. I conclude that, despite the promise of new traits and techniques, GM crops, including gene-edited crops, are unlikely to meet either the narrow agronomic or broader social and environmental requirements of sustainable agriculture. The review ends with a discussion of how plant breeders can best support and promote sustainable agriculture, and thus help create sustainable food systems.