Pearl millet genomic vulnerability to climate change in West Africa highlights the need for regional collaboration

Bénédicte Rhoné,Dimitri Defrance,Ndjido Ardo Kane,Marie Couderc,Cédric Mariac,Philippe Cubry,Aichatou Assoumanne,Yves Vigouroux,Cécile Berthouly-Salazar,Anaïs Dequincey,Benjamin Sultan,Adeline Barnaud

doi:10.1038/s41467-020-19066-4

Abstract

Climate change is already affecting agro-ecosystems and threatening food security by reducing crop productivity and increasing harvest uncertainty. Mobilizing crop diversity could be an efficient way to mitigate its impact. We test this hypothesis in pearl millet, a nutritious staple cereal cultivated in arid and low-fertility soils in sub-Saharan Africa. We analyze the genomic diversity of 173 landraces collected in West Africa together with an extensive climate dataset composed of metrics of agronomic importance. Mapping the pearl millet genomic vulnerability at the 2050 horizon based on the current genomic-climate relationships, we identify the northern edge of the current areas of cultivation of both early and late flowering varieties as being the most vulnerable to climate change. We predict that the most vulnerable areas will benefit from using landraces that already grow in equivalent climate conditions today. However, such seed-exchange scenarios will require long distance and trans-frontier assisted migrations. Leveraging genetic diversity as a climate mitigation strategy in West Africa will thus require regional collaboration.

Highlights

Climate change is already affecting agro-ecosystems and threatening food security by reducing crop productivity and increasing harvest uncertainty
Principal component analyses (PCAs) of SNP allele frequencies with complete data on landraces clearly separated according to their geographical origin (Fig. 1c, d) and landraces were found to cluster according to the country
The climate dataset consisted in 157 metrics of agronomical importance, i.e., onset of the monsoon and other metrics related to precipitation, temperature, and solar radiation (Supplementary Table 1)

Summary

Introduction

Climate change is already affecting agro-ecosystems and threatening food security by reducing crop productivity and increasing harvest uncertainty. Our analyses allow us to identify areas where pearl millet cultivation would be at greater risk under future climate conditions and to assess the agro-biodiversity potential of local varieties to mitigate the impact of climate change. These outcomes suggest that mitigating climate change for traditional African agriculture will require coordinated regional actions and long-scale migration of varieties

Methods

Results

Conclusion