Effect of elevated [CO2] on yield, intra-plant nutrient dynamics, and grain quality of rice cultivars in eastern India

BACKGROUND Climate models predict an increase in global temperature in response to a doubling of atmospheric [CO2]. This may affect future rice production and quality. In this study, the effect of elevated [CO2] on yield, nutrient acquisition and utilization, and grain quality of rice genotypes was investigated in the subtropical climate of eastern India (Kharagpur). Three environments (open field, ambient, and elevated [CO2]) were tested using four rice cultivars of eastern India. RESULTS CONCLUSION Under elevated [CO2] (25% higher), the yield of high-yielding cultivars (HYCs) viz IR 36, Swarna, and Swarna sub1 was significantly reduced (by 11-13%), whereas the yield increased (by 6-9%) for Badshabhog, a low-yielding aromatic cultivar. Elevated [CO2] significantly enhanced K uptake (by 14-21%), but did not influence the uptake of total N and P. The nutrient harvest index and use efficiency values in HYCs were reduced under elevated [CO2] indicating that nutrient translocation from source to sink (grain) was significantly reduced. An increase in alkali spreading value (10%) and reduction in grain protein (2-3%) and iron (5-6%) was also observed upon [CO2] elevation. The study highlights the importance of nutrient management (increasing N rate for HYCs) and selective breeding of tolerant cultivars in minimizing the adverse effects of elevated [CO2] on rice yield and quality. (c) 2018 Society of Chemical Industry