What is it about?

Agriculture is seen as both a key cause of the global “biodiversity crisis” and a principal means of addressing it. Unlike natural landscapes, agriculture is a highly managed system in which the genetic diversity of crops has both a spatial and temporal dimension. Using a century of wheat varietal use data for the US, we show that the increasingly intensive use of scientifically-selected crop varieties has led to more, not less, biodiverse cropping practices, at least regarding diversity in the U.S. wheat crop. This substantial increase in varietal diversity over the past century has been achieved in tandem with a fourfold increase in U.S. average wheat yields.

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Why is it important?

Agriculture is being asked to address an increasingly large number of sustainable development challenges. Key to addressing these challenges is the genetic diversity of the world’s staple food crops, wheat being the crop that occupies the largest acreage on the planet. Our results show that intelligently intensifying the use of scientifically selected varieties increased the genetic diversity of the cropping landscape throughout the US. However, public investment in crop breeding research is now on the decline in the US, and falls chronically short in many other, especially low-income, countries. To meaningfully build climate and pest resilience into the world's food crops in ways that also achieve global food security goals requires doubling down on crop improvement research that enhances not undermines crop biodiversity.


This paper uses 100-year long-run data for US wheat crop to demonstrate that scientifically intensive cropping system can be part of the solution to sustainable agricultural productivity growth. We hope the findings of our paper can have policy impacts on investments in modern science to address challenges posed by climate change, land and water scarcity, and new pest and disease threats.

Yuan Chai
University of Minnesota Twin Cities

Read the Original

This page is a summary of: Scientific selection: A century of increasing crop varietal diversity in US wheat, Proceedings of the National Academy of Sciences, December 2022, Proceedings of the National Academy of Sciences,
DOI: 10.1073/pnas.2210773119.
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