Finlay–Wilkinson's regression coefficient as a pre‐screening criterion for yield responsiveness to elevated atmospheric CO2 concentration in crops

The rising atmospheric CO₂ concentration (CO₂]) can increase crop productivity, but there are likely to be intraspecific variations in the response. To meet future world food demand, screening for genotypes with high CO₂] responsiveness will be a useful option, but there is no criterion for high CO₂] responsiveness. We hypothesized that the Finlay–Wilkinson regression coefficient (RC) (for the relationship between a genotype's yield versus the mean yield of all genotypes in a specific environment) could serve as a pre‐screening criterion for identifying genotypes that respond strongly to elevated CO₂]. We collected datasets on the yield of 6 rice and 10 soybean genotypes along environmental gradients and compared their responsiveness to elevated CO₂] based on the regression coefficients (i.e. the increases of yield per 100 µmol mol^?1 CO₂]) identified in previous reports. We found significant positive correlations between the RCs and the responsiveness of yield to elevated CO₂] in both rice and soybean. This result raises the possibility that the coefficient of the Finlay–Wilkinson relationship could be used as a pre‐screening criterion for CO₂] responsiveness.