Influence of Rising Atmospheric CO₂ Concentrations and Temperature on Morpho-Physiological Traits and Yield of Rice Genotypes in Sub Humid Climate of Eastern India

Abstract

A possible scenario for the end of the 21st century is that the atmospheric CO 2 concentration will be in the range of 510 - 760 μl · L -I and that the mean global temperature will be 1.5°C - 4.5°C higher than present day. One of the pre-eminent manifestations of climate change is the increase in atmospheric CO 2 concentration. Both CO 2 and temperature are the key variables of global climate and may cause significant changes in crop productivity. An experiment was conducted inside open top chamber (OTCs) in kharif season 2014 to evaluate the effects of CO 2 enrichment and temperature rise with condition OTC1 (ambient condition), OTC2 (25% higher CO 2 than ambient), OTC3 (25% higher CO 2 + 2°C > ambient temperature) and OTC4 (2°C > ambient temperature) on physiological traits and yield of rice genotypes to identify the suitable genotypes for changing climatic conditions. The study revealed that rice genotypes performed better under elevated CO 2 , with slight changes in development, such as growth and in yield attributing traits, depending on the genotypes. However, the beneficial direct impact of elevated (CO 2 ) on crop yield can be counteract by elevated temperatures. Rice genotype IR83376-B-B-24-2 was highly responsive while IR84895-B-127-CRA-5-1-1 was least responsive toward elevated CO 2 . Physiological traits like relative water content (RWC %), membrane stability index (MSI %), chlorophyll content, photosynthetic rate and TSS content were improved under elevated CO 2 . However, responses of these traits were negative with elevated temperature. We point out that studies related to changes in crop physiology and yield as a consequence of global climatic changes should be a priority due to their association with food security.