Abstract

Because of continuing increases in atmospheric CO₂, identifying cultivars of crops with larger yield increases at elevated CO₂ may provide an avenue to increase crop yield potential in future climates. Free-air CO₂ enrichment (FACE) systems have most often been used with multiple replications of each CO₂ treatment in order to increase confidence in the effect of elevated CO₂. For screening of cultivars for yield increases at elevated CO₂, less precision about the CO₂ effect, but more precision about cultivar ranking within CO₂ treatments is appropriate. As a small-scale test of this approach, three plots, each of four cultivars of wheat, were grown in single FACE and control plots over two years, and the cultivar rankings of yield at elevated and ambient CO₂ were compared. Each replicate plot was the size used in traditional cultivar comparisons. An additional test using four smaller replicate plots per cultivar within one FACE and one ambient plot was used to compare nine cultivars in another year. In all cases, elevated CO₂ altered the ranking of cultivars for yield. This approach may provide a more efficient way to utilize FACE systems for the screening of CO₂ responsiveness. View Full-Text