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Benefits of increasing transpiration efficiency in wheat under elevated CO2 for rainfed regions

journal contribution
posted on 07.05.2019, 00:00 by B Christy, Sabine Tausz-Posch, Michael Tausz, R Richards, G Rebetzke, A Condon, T McLean, G Fitzgerald, M Bourgault, G O'Leary
Higher transpiration efficiency (TE) has been proposed as a mechanism to increase crop yields in dry environments where water availability usually limits yield. The application of a coupled radiation and TE simulation model shows wheat yield advantage of a high-TE cultivar (cv. Drysdale) over its almost identical low-TE parent line (Hartog), from about −7 to 558 kg/ha (mean 187 kg/ha) over the rainfed cropping region in Australia (221–1,351 mm annual rainfall), under the present-day climate. The smallest absolute yield response occurred in the more extreme drier and wetter areas of the wheat belt. However, under elevated CO2 conditions, the response of Drysdale was much greater overall, ranging from 51 to 886 kg/ha (mean 284 kg/ha) with the greatest response in the higher rainfall areas. Changes in simulated TE under elevated CO2 conditions are seen across Australia with notable increased areas of higher TE under a drier climate in Western Australia, Queensland and parts of New South Wales and Victoria. This improved efficiency is subtly deceptive, with highest yields not necessarily directly correlated with highest TE. Nevertheless, the advantage of Drysdale over Hartog is clear with the benefit of the trait advantage attributed to TE ranging from 102% to 118% (mean 109%). The potential annual cost-benefits of this increased genetic TE trait across the wheat growing areas of Australia (5 year average of area planted to wheat) totaled AUD 631 MIL (5-year average wheat price of AUD/260 t) with an average of 187 kg/ha under the present climate. The benefit to an individual farmer will depend on location but elevated CO2 raises this nation-wide benefit to AUD 796 MIL in a 2°C warmer climate, slightly lower (AUD 715 MIL) if rainfall is also reduced by 20%. © 2018 The Authors. Global Change Biology Published by John Wiley & Sons Ltd

Funding

Category 1 - Australian Competitive Grants (this includes ARC, NHMRC)

History

Volume

24

Issue

5

Start Page

1965

End Page

1977

Number of Pages

13

eISSN

1365-2486

ISSN

1354-1013

Publisher

Wiley-Blackwell Publishing, UK

Additional Rights

CC BY 4.0

Peer Reviewed

Yes

Open Access

Yes

Acceptance Date

22/12/2017

External Author Affiliations

University of Melbourne; CSIRO; Department of Economic Development,Jobs, Transport and Resources, Agriculture Victoria Research

Era Eligible

Yes

Journal

Global Change Biology