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.

气候变化已经通过降低农作物的生产力和增加收成的不确定性，影响着农业生态系统并威胁着粮食安全。调动作物多样性可能是减轻其影响的有效方法。我们在撒哈拉以南非洲干旱和低肥力的土壤中种植的一种营养性主食谷物粟米中验证了这一假设。我们分析了在西非收集的173个地方品种的基因组多样性，以及由重要农业指标组成的广泛气候数据集。根据当前的基因组-气候关系，在2050年地平线上绘制珍珠粟的基因组脆弱性图，我们确定了早期和晚期开花品种当前种植区域的北部边缘最容易受到气候变化的影响。我们预测，最脆弱的地区将受益于使用已经在当今等效气候条件下生长的地方品种。但是，这种种子交换方案将需要长距离和跨边界协助的迁移。因此，利用遗传多样性作为西非的一项减缓气候变化战略将需要区域合作。