Soybean intraspecific genetic variation in response to elevated CO₂

Although elevated atmospheric CO2 concentration (elevated CO2 (eCO2)) considerably affect soybean yield, the agronomic and physiological contributors to the yield variation among cultivars in response to eCO2 have not been fully understood. Such investigation will fundamentally benefit future breeding strategies to enhance soybean adaptability to eCO2 environments. Twenty-four soybean cultivars were exposed to ambient CO2 (aCO2, 390 ppm) or eCO2 (580 ppm) throughout growth stages. The results showed the stimulation of eCO2 on soybean yield varied among cultivars, resulting in the increase from 3.3% in Yuanbaojin to 95% in Suinong 8. The yield gain under eCO2 was negatively correlated with yield under aCO2. The increases of the pod and seed number (sink) were strongly positive correlated (P2.