Intergenerational above- and belowground responses of spring wheat (Triticum aestivum L.) to elevated CO2

We quantified intergenerational above- and belowground responses of two genotypes of semi-dwarf, hard red, spring wheats (Triticum aestivum L.) to elevated (700 mumol mol(-1)) CO2. These plants were progeny of seeds produced from previous generation plants grown at elevated CO2 under well-watered and high nutrient conditions. Because neither genotype in the first generation exhibited enhanced performance with CO2 enrichment, our objective in this investigation was to assess if exposure to CO2 enrichment in subsequent generations resulted in temporal changes in the relative enhancement (elevated/ambient) of above- and belowground plant growth. Relative enhancement occurred in both the second and third generations for both above- and belowground variables. Above- and belowground variables were enhanced by similar relative amounts at elevated CO2 within a generation at each harvest date. Relative enhancement of measured variables was gen-erally greater in the third than second generation when plants were in the seedling or vegetative stage, but not when plants were reproductive. Additional research is needed to investigate physiological or other limitations of translating above- and belowground responses to CO2 in vegetative growth stages to reproductive performance. Intergenerational above- and belowground responses of this C-3 annual plant to CO2 enrichment are not driven by genetic change (selection) that occurred between generations, but rather CO2-induced changes in seeds that affected seedling responses to CO2 enrichment.