Rapid transgenerational adaptation in response to intercropping increases facilitation and reduces competition

By capitalising on positive biodiversity-productivity relationships, intercropping provides opportunities to improve agricultural sustainability¹. However, intercropping is generally implemented using commercial seeds that were bred for maximal productivity in monocultures, which might limit the benefits of crop diversity on yield^2,3. Plants can adapt over generations to the level of surrounding plant diversity, notably through increases in niche differentiation⁴. However, this adaptation potential and the corresponding yield benefit potential have not been explored in annual crop systems. Here we show that plant–plant interactions among annual crops evolved towards increased facilitation and reduced competition when the plants’ coexistence history matched their current diversity setting, which led to an increase in overyielding of up to 58%. These higher yield benefits were linked to character convergence between species sharing the same coexistence history for two generations. Notably, the six crop species tested converged towards taller phenotypes with lower leaf dry matter content when grown in mixtures. This study provides the first empirical evidence for the importance of parental diversity affecting plant–plant interactions and ecosystem functioning of the following generations in annual cropping systems. These results have important implications for diversified agriculture as they demonstrate the yield potential of targeted cultivars for intercropping, which can be achieved through specific breeding for mixtures.