Carbon dioxide fertilization effect on rice yield is not sustained over multiple generations

Global crop production needs to increase to meet the growing demand for food. Rising atmospheric CO 2 concentration offers opportunities to increase global productivity via the CO 2 fertilization effect on C 3 crops (including rice, Oryza sativa L.). However, whether the CO 2 fertilization effect can be sustained over generations remains unclear. Here, we show that the CO 2 fertilization effects on aboveground biomass, aboveground nitrogen uptake, and yield strongly depends on the number of generations in maternal elevated CO 2 (eCO 2 ) for rice cultivars Yangdao 6 (Y6; indica subspecies) and Wuyungeng 23 (W23; japonica subspecies) in free-air CO 2 enrichment (FACE) experiments. DNA methylation and transcriptome changes provided epigenetic evidence on the multigenerational effects of maternal eCO 2 on aboveground biomass, aboveground nitrogen uptake, and yield in both cultivars/subspecies. Our results highlight that data from multigenerational exposure to FACE experiments are needed to accurately predict crop production and food security in a future high-CO 2 world.