Changes in the Growth and Fruit Yield of Hot Peppers Grown under Elevated CO2 and Temperature Conditions

Climate change affects the growth of plants, and elevated CO2 concentrations and temperatures can cause leaf senescence and poor flower bud differentiation, which can reduce pepper production. Here, we undertook a quantitative evaluation of how elevated CO2 concentrations and temperatures compared to ambient conditions affect the growth and yield of peppers. Four CO2 concentration and temperature treatments were applied to the cultivation of the 'Hongchowang' variety pepper. The first treatment involved an ambient CO2 concentration and temperature, the second used an elevated CO2 concentration and an ambient temperature, the third used an ambient CO2 concentration and an elevated temperature, and the fourth used both an elevated CO2 concentration and elevated temperature. An elevated CO2 concentration caused decreases in the height, leaf area, and fruit yield, while an elevated temperature led to increases in the plant height, leaf area, and fruit yield. An elevated CO2 concentration increased the numbers of leaves and fruit as well as the leaf photosynthetic rate in peppers but also increased the IAA concentration, resulting in a large number of small leaves. On the other hand, an increase in the temperature caused an increase in the C/N ratio, increasing both the yield and number of fruit. In order to secure similar levels of pepper production under future climate change, a combination of measures against CO2 concentration and temperature increases will be required.