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Elevated atmospheric [CO2] can dramatically increase wheat yields in semi-arid environments and buffer against heat waves

journal contribution
posted on 06.08.2019, 00:00 authored by GJ Fitzgerald, Michael Tausz, G O'Leary, MR Mollah, Sabine Tausz-Posch, S Seneweera, I Mock, M Löw, DL Partington, D McNeil
Wheat production will be impacted by increasing concentration of atmospheric CO2 [CO2], which is expected to rise from about 400 μmol mol-1 in 2015 to 550 μmol mol-1 by 2050. Changes to plant physiology and crop responses from elevated [CO2] (e[CO2]) are well documented for some environments, but field-level responses in dryland Mediterranean environments with terminal drought and heat waves are scarce. The Australian Grains Free Air CO2 Enrichment facility was established to compare wheat (Triticum aestivum) growth and yield under ambient (~370 μmol-1 in 2007) and e[CO2] (550 μmol-1) in semi-arid environments. Experiments were undertaken at two dryland sites (Horsham and Walpeup) across three years with two cultivars, two sowing times and two irrigation treatments. Mean yield stimulation due to e[CO2] was 24% at Horsham and 53% at Walpeup, with some treatment responses greater than 70%, depending on environment. Under supplemental irrigation, e[CO2] stimulated yields at Horsham by 37% compared to 13% under rainfed conditions, showing that water limited growth and yield response to e[CO2]. Heat wave effects were ameliorated under e[CO2] as shown by reductions of 31% and 54% in screenings and 10% and 12% larger kernels (Horsham and Walpeup). Greatest yield stimulations occurred in the e[CO2] late sowing and heat stressed treatments, when supplied with more water. There were no clear differences in cultivar response due to e[CO2]. Multiple regression showed that yield response to e[CO2] depended on temperatures and water availability before and after anthesis. Thus, timing of temperature and water and the crop's ability to translocate carbohydrates to the grain postanthesis were all important in determining the e[CO2] response. The large responses to e[CO2] under dryland conditions have not been previously reported and underscore the need for field level research to provide mechanistic understanding for adapting crops to a changing climate. © 2016 John Wiley & Sons Ltd.

Funding

Category 3 - Industry and Other Research Income

History

Volume

22

Issue

6

Start Page

2269

End Page

2284

Number of Pages

16

eISSN

1365-2486

ISSN

1354-1013

Publisher

Wiley-Blackwell Publishing, UK

Additional Rights

CC BY-NC-ND 4.0

Peer Reviewed

Yes

Open Access

Yes

Acceptance Date

10/02/2016

External Author Affiliations

University of Melbourne; Tasmanian Institute of Agriculture; International Plant Nutrition Institute, Dodgshun Medlin Agricultural Management, Victoria; University of Southern Queensland; Victorian Department of Economic Development, Jobs, Transport and Resources

Era Eligible

Yes

Journal

Global Change Biology