Impact of elevated temperature and carbon dioxide-varietal differences in response of biomass, seed yield and oil quality of groundnut (Arachis hypogaea L.)

The major impacts of climate change on productivity of crops are increased atmospheric temperature and enhanced concentration of carbon dioxide. The present field study under Free Air Temperature Elevation (FATE) facility dealt with impact of elevated temperature of +3°C (eT) and in combination with elevated CO₂ of 550 ppm (eT + eCO₂) on biomass, seed yield and oil quality of four groundnut (Arachis hypogaea L.) varieties - Narayani, Dharani, K-6 and K-9. The experiment was conducted during summer season of 2022 when ambient temperature was higher than crop threshold temperature. The elevated temperature (eT) impacted the biomass and yield components of groundnut varieties and the presence of elevated CO₂ ameliorated the impacts of eT to some extent. The varieties K-6 and Narayani are sensitive to high temperature and responsive to eCO₂ as reduction of their yield components was highest with eT as well as amelioration with eCO₂ was also high. The variety K-9 with improved pod number and seed weight at eT showed better tolerance to higher temperature, however its response to eCO₂ was minimum. The eT and eT+eCO₂ conditions significantly altered the seed oil content, saturated and unsaturated fatty acid levels of groundnut varieties. The eT condition improved the oil content in K-6 and K-9, while eT+eCO₂ condition improved it in Dharani, K-6 and K-9_. The improved O/L ratio of the oil in the presence of eCO₂ was due to increased proportion of oleic acid (18:1) (omega-9) and decrease in linoleic acid (18:2) level and this aspect is important in human nutritional point of view under future predicted changed climatic conditions.