Effects of Elevated CO2 on Rice Harvest Components

Rice (Oryza sativa L.) has long been a staple food for people across various nations, particularly in Asia. Climate change and rising atmospheric carbon dioxide (CO₂) levels now have diverse impacts on crop performance worldwide. Since CO₂ is a key factor in photosynthesis, it enhances productivity and yield. This study investigated the effects of elevated CO₂ (eCO₂) on rice yield improvement. Using a novel approach, rice seedlings were only exposed to high CO₂ levels during the early vegetative stage. The treatments included eCO₂ (600 to 800 µmol mol⁻¹), ambient CO₂ [aCO₂ (410-415 µmol mol⁻¹)], and a control under field conditions. Following treatment with eCO₂, the seedlings were transplanted into a rain shelter in a two-factorial randomized complete block design (RCBD). Results showed that tiller number per plant, panicle number per plant, and panicle length increased by 18.38%, 20.96%, and 14.15%, respectively, with eCO₂. Additionally, filled grain per panicle and grain yield increased by 15.30% and 47.48%, respectively. In conclusion, eCO₂ treatment significantly improved rice yield components during the seedling stage. Applying eCO₂ sustainably could increase rice yield, supporting Afghanistan in achieving rice self-sufficiency in the future. Temporary eCO₂ treatment on rice seedlings may enhance rice production, improving farmers' incomes and living standards.