Nutritional quality in response to elevated CO2 concentration in foxtail millet (Setaria italica)

Increasing atmospheric CO2 concentration may affect human health through its effects on crop production and nutrition. Foxtail millet, a nutritious C-4 cereal, is superior to major cereals subjected to environmental stresses. The effects of elevated CO2 concentration (eCO(2)) on foxtail millet (Setaria italica) remain unclear. In this study, the yield and nutritional quality of foxtail millet were investigated under ambient [CO2] (approximately 400 mu mol mol(-1)) or eCO(2) (approximately 600 mu mol mol(-1)) for 3 years by using open-top chambers (OTCs). The yield and biomass production of foxtail millet was significantly enhanced under eCO(2). In addition, eCO(2) significantly affected the concentration of protein and oil in grains, but it had no effect on starch concentration across the three years. Elevated [CO2] strongly decreased the Fe concentration in foxtail millet, but it did not affect the concentration of K, Ca, Cu, or Zn. Moreover, the grain mineral accumulation of K, Mn, Zn, and the grain accumulation of starch were significantly increased under eCO(2) across the three years. In particular, eCO(2) significantly increased the concentration and accumulation of P across the three years. eCO(2) had a slight effect on the nutritional quality of foxtail millet. These results suggest that the climate change-resilient C-4 model crop holds with great promise for food security and nutrition under eCO(2).