Intraspecific responses of plant productivity and crop yield to experimental warming: A global synthesis

Maintaining plant productivity and crop yield in a warming world requires local adaptation to new environment and selection of high-yield cultivars, which both depend on the genetically-based intraspecific differences in the plant response to warming (referred to as "genetically-based intraspecific responses"). However, how the genetically-based intraspecific responses mediate warming effects on plants remains unclear, especially at the global scale. Here, a dataset was compiled from 118 common-garden experiments to examine the responses of plant growth, productivity, and crop yield to warming among different ecotypes/genotypes/cultivars. Our results showed that the genetically-based intraspecific responses on average accounted for 34.7 % of the total variance in the warming responses across all the studies but with large variability (2 %-77 %). The intraspecific responses of plant productivity and crop yield were larger than those of organ level traits and biomass allocation, suggesting that plant growth was mainly achieved by iterating the relatively invariant terminal modules (e.g., leaves). The warming-induced changes in intraspecific variability of aboveground biomass were larger in woody plants, non-leguminous herbs, perennial herbs and noncrops than those in nonwoody, leguminous, annual and crop ones, respectively, indicating the potential important role of plant longevity in mediating the change in intraspecific variability. Moreover, larger intraspecific responses reduced the consistence of relative performance between control and warming treatments for both plant productivity and crop yield. These results highlight the unneglectable role of genetically-based intraspecific differences in plant responses to warming, indicating the difficulty of maintaining high crop yield and tree productivity under global climate change, and posing a grave threat to the food security and wood supply in the near future.