Using FACE Systems to Screen Wheat Cultivars for Yield Increases at Elevated CO2

James Bunce

doi:10.3390/agronomy7010020

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.

Highlights

The CO2 concentration in the atmosphere continues to increase rapidly, and may increase yields of C3 crops, helping to meet the expected increased demand for agricultural products
In the first experiment, which compared responses of four cultivars in two different years, significant differences among cultivars occurred for seed yield both at ambient and elevated CO2, at p = 0.05 in both years (Table 1)
The ranking of the yields Pioneer 25 R32 and Jamestown responded to the CO2 treatment in the same way as in the first year, that is, the ranking of Jamestown increased at elevated CO2, and the ranking of Pioneer 25 R32 deceased at elevated CO2 (Table 1)

Summary

Introduction

The CO2 concentration in the atmosphere continues to increase rapidly, and may increase yields of C3 crops, helping to meet the expected increased demand for agricultural products. Intraspecific variation in the responsiveness of yield has been reported in many C3 crops species: barley [1], common bean [2], cow pea [3], oat [4], rape [5], rice [6,7], soybean [8,9], and wheat [10,11]. Such variation could allow the achievement of larger field yield increases as CO2 rises, if new cultivars could be developed to better exploit the rising CO2 [12]. The FACE rings were 20 m in diameter for soybean (but only one-half of the plot was used for the 18 cultivars), and 17 m diameter for rice

Methods

Results

Conclusion