Crop genetic erosion: understanding and responding to loss of crop diversity

• Published in: The New phytologist Vol. 233; no. 1; pp. 84 - 118
• Main Authors: Khoury, Colin K., Brush, Stephen, Costich, Denise E., Curry, Helen Anne, Haan, Stef, Engels, Johannes M. M., Guarino, Luigi, Hoban, Sean, Mercer, Kristin L., Miller, Allison J., Nabhan, Gary P., Perales, Hugo R., Richards, Chris, Riggins, Chance, Thormann, Imke
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.01.2022
• Subjects: Agriculture; agrobiodiversity; analytical methods; biodiversity conservation; Conservation; Conservation of Natural Resources; Crop diversification; crop diversity; crop landraces; crop wild relatives; Crops; Crops, Agricultural - genetics; Cultivars; diachronic diversity; Ecosystem; Farms; food security; Genetic diversity; genetic erosion; Genetic resources; landraces; plant genetic resources; Wild type; crop landraces; crop diversity; agrobiodiversity; crop wild relatives; food security; biodiversity conservation; diachronic diversity; plant genetic resources
• ISSN: 0028-646X; 1469-8137; 1469-8137
• DOI: 10.1111/nph.17733

Summary Crop diversity underpins the productivity, resilience and adaptive capacity of agriculture. Loss of this diversity, termed crop genetic erosion, is therefore concerning. While alarms regarding evident declines in crop diversity have been raised for over a century, the magnitude, trajectory, drivers and significance of these losses remain insufficiently understood. We outline the various definitions, measurements, scales and sources of information on crop genetic erosion. We then provide a synthesis of evidence regarding changes in the diversity of traditional crop landraces on farms, modern crop cultivars in agriculture, crop wild relatives in their natural habitats and crop genetic resources held in conservation repositories. This evidence indicates that marked losses, but also maintenance and increases in diversity, have occurred in all these contexts, the extent depending on species, taxonomic and geographic scale, and region, as well as analytical approach. We discuss steps needed to further advance knowledge around the agricultural and societal significance, as well as conservation implications, of crop genetic erosion. Finally, we propose actions to mitigate, stem and reverse further losses of crop diversity.