Transpiration efficiency: new insights into an old story

Vadez, V and Kholova, J and Medina, Susan and Kakkera, A and Anderberg, Hanna (2014) Transpiration efficiency: new insights into an old story. Journal of Experimental Botany, 65 (21). pp. 6141-6153. ISSN 0022-0957

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Abstract

Producing more food per unit of water has never been as important as it is at present, and the demand for water by economic sectors other than agriculture will necessarily put a great deal of pressure on a dwindling resource, leading to a call for increases in the productivity of water in agriculture. This topic has been given high priority in the research agenda for the last 30 years, but with the exception of a few specific cases, such as water-use-efficient wheat in Australia, breeding crops for water-use efficiency has yet to be accomplished. Here, we review the efforts to harness transpiration efficiency (TE); that is, the genetic component of water-use efficiency. As TE is difficult to measure, especially in the field, evaluations of TE have relied mostly on surrogate traits, although this has most likely resulted in over-dependence on the surrogates. A new lysimetric method for assessing TE gravimetrically throughout the entire cropping cycle has revealed high genetic variation in different cereals and legumes. Across species, water regimes, and a wide range of genotypes, this method has clearly established an absence of relationships between TE and total water use, which dismisses previous claims that high TE may lead to a lower production potential. More excitingly, a tight link has been found between these large differences in TE in several crops and attributes of plants that make them restrict water losses under high vapour-pressure deficits. This trait provides new insight into the genetics of TE, especially from the perspective of plant hydraulics, probably with close involvement of aquaporins, and opens new possibilities for achieving genetic gains via breeding focused on this trait. Last but not least, small amounts of water used in specific periods of the crop cycle, such as during grain filling, may be critical. We assessed the efficiency of water use at these critical stages.

Item Type: Article
Divisions: RP-Dryland Cereals
CRP: CGIAR Research Program on Dryland Cereals
Uncontrolled Keywords: Aquaporins, carbon-isotope discrimination, CID, drought, grain filling, hydraulics, post-anthesis water use, vapourpressure deficit, VPD, water stress
Subjects: Others > Plant Physiology
Depositing User: Siva Shankar
Date Deposited: 10 Mar 2014 04:58
Last Modified: 04 Sep 2017 08:37
URI: http://oar.icrisat.org/id/eprint/7603
Official URL: http://dx.doi.org/10.1093/jxb/eru040
Projects: UNSPECIFIED
Funders: UNSPECIFIED
Acknowledgement: The senior author wishes to acknowledge support from the Bill and Melinda Gates Foundation through a grant to the Generation Challenge Program (Tropical Legume I project), the CGIAR Research Program on Dryland Cereals (CRP-DC) and Grain Legumes (CRP-GL), and the Research Program on Climate Change, Agriculture and Food Security (CCAFS), which have supported some of the research presented in this review.
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