Water scarcity is the primary environmental constraint affecting wheat growth and production and is increasingly exacerbated due to climatic fluctuation, which jeopardizes future food security. Most breeding efforts to improve wheat yields under drought have focused on above-ground traits. Root traits are closely associated with various drought adaptability mechanisms, but the genetic variation underlying these traits remains untapped, even though it holds tremendous potential for improving crop resilience. Here, we examined this potential by re-introducing ancestral alleles from wild emmer wheat (Triticum turgidum ssp. dicoccoides) and studied their impact on root architecture diversity under terminal drought stress. We applied an active sensing electrical resistivity tomography approach to compare a wild emmer introgression line (IL20) and its drought-sensitive recurrent parent (Svevo) under field conditions. IL20 exhibited greater root elongation under drought, which resulted in higher root water uptake from deeper soil layers. This advantage initiated at the pseudo-stem stage and increased during the transition to the reproductive stage. The increased water uptake promoted higher gas exchange rates and enhanced grain yield under drought. Overall, we show that this presumably 'lost' drought-induced mechanism of deeper rooting profile can serve as a breeding target to improve wheat productiveness under changing climate.
Bibliographical noteFunding Information:
This research was supported by the U.S. Agency for International Development Middle East Research and Cooperation (grant no. M34-037) and the Chief Scientist of the Israeli Ministry of Agriculture and Rural Development (grant no. 12-01-0056).
© 2023 The Author(s). Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved.
- Active sensing
- deeper rooting
- electrical resistivity tomography (ERT)
- gas exchange
- root architecture tradeoff
- root water uptake
- terminal drought