Effect of Elevated CO2 and Temperature on Chlorophyll Content and Growth Attributes of Rice-wheat Cropping System in Central India

Rice-wheat is a major cropping system in India and it is predicted that the productivity of both crops will decline due to climate change factors including elevated CO2 and temperature. To define the mechanisms, a field experiment was carried out to evaluate the effect of elevated CO2 and temperature on growth attributes of rice and wheat crops using a Free Air CO2 Enrichment (FACE) system. The treatments were ambient CO2+ambient temperature, elevatedCO2of 600ppm+ambient temperature, ambient CO2 + elevated temperature (+2°C), ambient CO2+elevated temperature (+3°C), elevated CO2 600 ppm +elevated temperature (+2°C) and elevated CO2 600ppm +elevated temperature (+3°C). Elevated CO2 and elevated temperature (+2°C or +3°C) strongly affected the crop growth. Elevated CO2 stimulated leaf chlorophyll content, root-shoot length and biomass yield. However, elevated temperature inhibited chlorophyll content in both the crops. Elevated CO2enhanced chlorophyll content by 12.9–19% in rice and 8.8–16.5%in wheat. Elevated temperature reduced chlorophyll content by a range of 20.5-27.3% in rice and 6.3-11.5% in wheat. Combined effect of elevated CO2and elevated temperature decreased the leaf total chlorophyll and plant biomass in both crops. Study highlights that elevated CO2 concentration and rising temperature may affect the photosynthesis and productivity of rice and wheat crop in central India.