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Yield gains larger in GM maize for human consumption than livestock feed in South Africa

Abstract

The majority of genetically modified (GM) crops are produced for livestock consumption, whereas minimal attention has been given to GM crops for direct human consumption. In South Africa, GM white maize has been grown for direct human consumption alongside GM yellow maize and conventional hybrid (CH) maize for livestock feed since 1999. Here we investigate yield differences between GM white, GM yellow and CH maize across 106 locations, 28 years, 491 cultivars, and 49,335 dryland and 9,617 irrigated observations in South Africa. GM maize increased mean yields over CH by 0.42 metric tons (Mt) ha−1 and reduced yield risk. We show that GM white maize increased yields by 0.60 Mt ha−1 and GM yellow maize by 0.27 Mt ha−1 compared with CH maize. GM yield gains were similar for dry and irrigated production. Our study highlights the potential impacts of growing GM grain crops for human consumption in African countries.

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Fig. 1: Comparison of maize yields for South African trial data for 1980–2009.

Data availability

The data that support the findings of this study were provided by the South Africa ARC and are available from the corresponding author upon request and with approval from the ARC.

Code availability

The Stata v.15 code that supports the findings of this study is available from the corresponding author upon request.

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Acknowledgements

We acknowledge and thank the South Africa Agricultural Research Council–Grain Crops Institute (ARC-GCI) for providing access to the data used in this study. All opinions expressed in this paper are the authors’ and do not necessarily reflect the policies and views of ARC-GCI.

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Authors

Contributions

A.M.S., J.B.T., L.L.N., P.C. and S.M. conceptualized the study and performed research. P.C. and S.M. collected and synthesized data. A.M.S., J.B.T. and L.L.N. designed the study. A.M.S. and J.B.T. analysed data. A.M.S., J.B.T. and L.L.N. wrote the manuscript. A.M.S., J.B.T., L.L.N., P.C. and S.M. revised the final manuscript.

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Correspondence to Aaron M. Shew.

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The authors declare no competing interests.

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Peer review information Nature Food thanks G. Slafer, S. Smyth and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary Information

Supplementary Tables 1–3 and Fig. 1.

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Shew, A.M., Tack, J.B., Nalley, L.L. et al. Yield gains larger in GM maize for human consumption than livestock feed in South Africa. Nat Food 2, 104–109 (2021). https://doi.org/10.1038/s43016-021-00231-x

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