Atmospheric CO2 enrichment affects potatoes: 1. Aboveground biomass production and tuber yield

Despite its economic and environmental importance, information about effects of future atmospheric carbon dioxide (CO2) enrichment on aboveground biomass production and tuber yield of potato is still rare. Responses of potato (Solanum tuberosum L. cv. Bintje) were thus investigated in two full growing seasons under 380, 550 or 680 μmol mol−1 CO2 in open-top chambers (OTCs). When averaged over both years, aboveground stem biomass at canopy maturity was negatively related to CO2 enrichment. Aboveground-to-belowground biomass ratio was negatively related to CO2 enrichment as there was a positive relationship between CO2 and total dry yield of potato tubers. The stimulation was mainly related to an increase in the tuber size fraction for commercial yield (tubers > 35 mm). For the largest size class (tubers > 50 mm), which is important for industrial processing, large CO2-induced impacts were observed too, although these effects were not significant. Elevated CO2 concentrations will thus affect biomass allocation of potato plants and result in improvements concerning the market value of the commercial tuber yield.