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.