A low-cost method to rapidly and accurately screen for transpiration efficiency in wheat

Andrew Fletcher; Jack Christopher; Mal Hunter; Greg Rebetzke; Karine Chenu

doi:10.1186/s13007-018-0339-y

A low-cost method to rapidly and accurately screen for transpiration efficiency in wheat

Plant Methods. 2018 Aug 29:14:77. doi: 10.1186/s13007-018-0339-y. eCollection 2018.

Authors

Andrew Fletcher¹, Jack Christopher², Mal Hunter³, Greg Rebetzke⁴, Karine Chenu¹

Affiliations

¹ 1Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, 203 Tor Street, Toowoomba, QLD 4350 Australia.
² 2Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, 13 Holberton Street, Toowoomba, QLD 4350 Australia.
³ 3School of Agriculture and Food Sciences, The University of Queensland, St Lucia, 4072 Australia.
⁴ 4CSIRO Plant Industry, PO Box 1600, Canberra, ACT 2601 Australia.

Abstract

Background: Wheat (Triticum aestivum L.) productivity is commonly limited by the availability of water. Increasing transpiration efficiency (biomass produced per unit of water used, TE) can potentially lead to increased grain yield in water-limited environments ('more crop per drop'). Currently, the ability to screen large populations for TE is limited by slow, low-throughput and/or expensive screening procedures. Here, we propose a low-cost, low-technology, rapid, and scalable method to screen for TE. The method uses a Pot-in-Bucket system that allows continuous watering of the pots and frequent monitoring of water use. To investigate the robustness of the method across environments, and to determine the shortest trial duration required to get accurate and repeatable TE estimates in wheat, plants from 11 genotypes varying in phenology were sown at three dates and grown for different durations in a polyhouse with partial environmental control.

Results: The method revealed significant genotypic variations in TE among the 11 studied wheat genotypes. Genotype rankings for TE were consistent when plants were harvested the same day, at the flag-leaf stage or later. For these harvests, genotype rankings were consistent across experiments despite changes in environmental conditions, such as evaporative demand.

Conclusions: These results indicate that (1) the Pot-In-Bucket system is suitable to screen TE for breeding purposes in populations with varying phenology, (2) multiple short trials can be carried out within a season to allow increased throughput of genotypes for TE screening, and (3) root biomass measurement is not required to screen for TE, as whole-plant TE and shoot-only TE are highly correlated, at least in wheat. The method is particularly relevant in developing countries where low-cost and relatively high labour input may be most applicable.

Keywords: Breeding; Cereal; Crop adaptation; Crop improvement; Drought; Phenotyping platform; Transpiration; Triticum aestivum; Water deficit; Water stress; Water use; Water use efficiency; Wheat.