Grain growth of different rice cultivars under elevated CO 2 concentrations affects yield and quality

•Grain yield and quality of rice cultivars with different panicle structures were differentially affected by elevated CO2.•Grain yield stimulation by elevated CO2were less panicle structure related, while grain quality response were rice cultivar dependent.•Differential responses of grains located at different positions within a rice panicle were found.•Key factors for a rice to gain a higher yield and maintain grain quality under elevated CO2were suggested.