The climatic constrains of the historical global spread of mungbean

While the domestication process has been investigated in many crops, the detailed route of cultivar range expansion and factors governing this process received relatively little attention. Here using mungbean ( Vigna radiata var. radiata ) as a test case, we investigated the genomes of more than one thousand accessions to illustrate climatic adaptation’s role in dictating the unique cultivar spread routes in the face of continual human intervention. Despite the geographical proximity between South and Central Asia, mungbean cultivars first spread from South Asia to Southeast, East, and finally reached Central Asia. Combining evidence from demographic inference, climatic niche modeling, plant morphology, and records from ancient Chinese sources, we showed that the specific spread route was shaped by the unique combinations of climatic constraints and farmer practices across Asia, which imposed divergent selection favoring higher yield in the south but short-season and more drought-tolerant varieties in the north. Our results suggest that mungbean did not radiate from the domestication center as expected purely under human activity, but instead the spread route is highly constrained by climatic adaptation, echoing the idea that human commensals are more difficult to spread through the south-north axis of continents. ### Competing Interest Statement The authors have declared no competing interest.