Effect of Carbon Dioxide Levels on Virulence and Physiological Parameters in Association with Stem Rot Disease of Groundnut

Background: Stem rot of groundnut (Arachis hypogaea L.) caused by Scelrotium rolfsii is the main threat to groundnut production, causing significant economic losses both in India and globally. Despite the economic losses attributed to this pathogen, there are limited reports concerning the virulence and physiological alterations in groundnut in response to increased carbon dioxide levels and pathogen interactions. Methods: A pot culture experiment was carried out at ICRISAT during the rabi season of 2022-23 in Open Top Chambers (OTC) to assess the virulence and physiological parameters of groundnut to climate change and pathogen interactions. The study was carried out at three different carbon dioxide levels (400 ppm, 550 ppm and 700 ppm) using the susceptible cultivar TMV 2 and the moderately resistant cultivar ICGV-14082. Result: Virulence of the Sclerotium rolfsii and physiological responses of groundnut plants were studied. Groundnut plants were grown in open top chambers (OTC) under three different simulated carbon dioxide levels, 400 ppm, 550 ppm and 700 ppm. Virulence of Sclerotium rolfsii decreased at increased levels of carbon dioxide levels in both TMV-2 and ICGV-14082 cultivars. Stomatal density and guard cell length in groundnut leaves were decreased as carbon dioxide levels increased.