The expected rise in [CO2] concentration from 400 to 550 μmol mol⁻¹ by the middle of this century will have a significant impact on crop productivity and quality. For C3 plant species, photosynthesis, biomass, and yield will be substantially increased at elevated CO2 levels, whereas only a small increase will be observed for C4 plants. For both C4 and C3 species, stomatal conductance will
... [Show full abstract] significantly be reduced, and this will greatly improve the water use efficiency in all the functional groups. Elevated CO2 will modify many of the grain quality traits such as proteins, minerals (zinc and iron), fatty acid composition, and starch properties. However, when accompanied by rising temperatures and periodic drought, some of the positive impacts on crop yield will be reduced. Therefore, a fundamental understanding of the physiological and genetic mechanisms underlying the response of crop plants to high CO2 is important to prepare effectively for food security issues in the future. Further, understanding the genetic basis for responding to elevated CO2 and breeding new crops adapted is essential to address immediate global food security concerns.