Comparison of multi-stress resilience in wild and domesticated Cowpea

A common hypothesis in plant science is that wild relatives of crops possess greater resilience to multiple stresses because they retain adaptive traits that have been diminished through domestication. Such reductions in resilience in cultivated crops are often attributed to trade-offs, whereby selection for agronomic performance decreases investment in stress tolerance. Alternatively, weakened multi-stress resilience may arise from relaxed natural selection in managed environments, where crops experience fewer ecological pressures. Vigna unguiculata, cowpea, is crucial for food security in arid and semi-arid regions due to its inherent stress tolerance, low input requirements, and nitrogen-fixing capacity. To test whether wild cowpea genotypes exhibit stronger multi-stress resilience than cultivated forms, we conducted a controlled full-factorial experiment using geographically and genetically diverse germplasm. Fourteen wild and cultivated genotypes spanning gradients in temperature, precipitation, and dry-season length were exposed to simulated drought and herbivory. We quantified growth responses and assessed trait variability using the coefficient of variation. Drought, herbivory, and their interaction significantly reduced productivity across all Vigna genotypes. However, wild types exhibited lower phenotypic variability and more consistent performance across stress treatments, suggesting that domestication may have reduced the stability of multi-stress responses. These findings improve our understanding of stress adaptation in cowpea and highlight the value of wild germplasm for breeding climate-resilient legumes.