Climate change is expected to severely impact cultivated plants and consequently human livelihoods 1-3 , especially in Sub-Saharan Africa (SSA) 4-6. Increasing agricultural plant diversity (agrobiodiversity) could overcome this global challenge 7-9 given more information on the climatic tolerance of crops and their wild relatives. Using >200,000 worldwide occurrence records for 29 major crops and 778 of their wild relative species, we assess for each crop how future climatic conditions are expected to change in SSA and whether populations of the same 2 crop from other continents, wild relatives around the world, or other crops from SSA are better adapted to expected future climatic conditions in the region. We show that climate conditions not currently experienced by the 29 crops in SSA are predicted to become widespread, increasing production insecurity, especially for yams. However, crops such as potato, squash and finger millet may be maintained by using wild relatives or non-African crop populations with climatic niches more suited to future conditions. Crop insecurity increases over time and rising greenhouse gas emissions, but the potential for using agrobiodiversity for resilience is less altered. Climate change will therefore affect Sub-Saharan agriculture but agrobiodiversity can provide resilient solutions in the short-and medium-term. Main Text: Global climate has changed rapidly over recent decades, and temperature and precipitation regimes are predicted to shift significantly in the near future 10. Future impacts on both biodiversity and human livelihoods are significant and primarily negative 2,4,11. By affecting plant productivity, and thus industrial and food crop yield, climate change is expected to impact global human economy and subsistence 1,2. Its tropical location, socioeconomic, demographic, policy, and farming characteristics place sub-Saharan Africa (SSA) at major risk 5,6. Assessing which sub-Saharan crops, regions and populations will be most affected, as well as potential future adaptations is therefore essential. Agrobiodiversity and breeding programs represent an important adaptive strategy for agriculture in a changing world 8,12. Currently cultivated crops may exhibit reduced genetic variation compared to that found in wild relative populations, which may limit their resilience and adaptation to future environmental conditions 13. Crop improvement through selection for

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Global biodiversity hotspots are areas containing high levels of species richness, endemism and threat. Similarly, regions of agriculturally relevant diversity have been identified where many domesticated plants and animals originated, and co-occurred with their wild ancestors and relatives. The agro-biodiversity in these regions has, likewise, often been considered threatened. Biodiversity and agro-biodiversity hotspots partly overlap, but their geographic intricacies have rarely been investigated together. Here we review the history of these two concepts and explore their geographic relationship by analysing global distribution and human use data for all plants, and for major crops and associated wild relatives. We highlight a geographic continuum between agro-biodiversity hotspots that contain high richness in species that are intensively used and well known by humanity (i.e., major crops and most viewed species on Wikipedia) and biodiversity hotspots encompassing species that are less heavily used and documented (i.e., crop wild relatives and species lacking information on Wikipedia). Our contribution highlights the key considerations needed for further developing a unifying concept of agro-biodiversity hotspots that encompasses multiple facets of diversity (including genetic and phylogenetic) and the linkage with overall biodiversity. This integration will ultimately enhance our understanding of the geography of human-plant interactions and help guide the preservation of nature and its contributions to people.

Dwarf birch (Betula nana) has a widespread boreal distribution but has declined significantly in Britain where populations are now highly fragmented. We analyzed the genetic diversity of these fragmented populations using markers that differ in mutation rate: conventional microsatellites markers (PCR-SSRs), RADseq generated transition and transversion SNPs (RAD-SNPs), and microsatellite markers mined from RADseq reads (RAD-SSRs). We estimated the current population sizes by census and indirectly, from the linkage-disequilibrium found in the genetic surveys. The two types of estimate were highly correlated. Overall, we found genetic diversity to be only slightly lower in Britain than across a comparable area in Scandinavia where populations are large and continuous. While the ensemble of British fragments maintain diversity levels close to Scandinavian populations, individually they have drifted apart and lost diversity; particularly the smaller populations. An ABC analysis, based on coalescent models, favors demographic scenarios in which Britain maintained high levels of genetic diversity through post-glacial re-colonization. This diversity has subsequently been partitioned into population fragments that have recently lost diversity at a rate corresponding to the current population-size estimates. We conclude that the British population fragments retain sufficient genetic resources to be the basis of conservation and re-planting programmes. Use of markers with different mutation rates gives us greater confidence and insight than one marker set could have alone, and we suggest that RAD-SSRs are particularly useful as high mutation-rate marker set with a well-specified ascertainment bias, which are widely available yet often neglected in existing RAD datasets.

Ensete ventricosum (Musaceae, enset) is an Ethiopian food security crop. To realize the potential of enset for rural livelihoods, further knowledge of enset diversity, genetics and genomics is required to support breeding programs and conservation. This study was conducted to explore the enset genome to develop molecular markers, genomics resources, and characterize enset landraces while giving insight into the organization of the genome. We identified 233 microsatellites (simple sequence repeats, SSRs) per Mbp in the enset genome, representing 0.28% of the genome. Mono- and di-nucleotide repeats motifs were found in a higher proportion than other classes of SSR-motifs. In total, 154,586 non-redundant enset microsatellite markers (EMM) were identified and 40 selected for primer development. Marker validation by PCR and low-cost agarose gel electrophoresis revealed that 92.5% were polymorphic, showing a high PIC (Polymorphism Information Content; 0.87) and expected heterozygosity (He = 0.79–0.82). In silico analysis of genomes of closely related species showed 46.86% of the markers were transferable among enset species and 1.90% were transferable to Musa. The SSRs are robust (with basic PCR methods and agarose gel electrophoresis), informative, and applicable in measuring enset diversity, genotyping, selection and potentially breeding. Enset SSRs are available in a web-based database at https://enset-project.org/EnMom@base.html (or https://enset.aau.edu.et/index.html, downloadable from Figshare).