Stress-induced deeper rooting introgression enhances wheat yield under terminal drought

Area of Science:

• Plant science
• Agronomy
• Genetics

Background:

• Water scarcity is a major threat to wheat production and global food security, intensified by climate change.
• Current wheat breeding prioritizes above-ground traits, neglecting the significant potential of root traits for drought adaptation.
• Ancestral genetic resources, like wild emmer wheat, offer untapped variation for improving crop resilience.

Purpose of the Study:

• To investigate the impact of re-introducing ancestral alleles from wild emmer wheat (Triticum turgidum ssp. dicoccoides) on root architecture.
• To assess the effectiveness of these genetic modifications in enhancing drought tolerance and yield in wheat under terminal drought stress.

Main Methods:

• Utilized active sensing electrical resistivity tomography for non-invasive root system analysis.
• Compared a wild emmer introgression line (IL20) with its drought-sensitive recurrent parent (Svevo) under field conditions.
• Evaluated root architecture, water uptake, gas exchange, and grain yield under terminal drought stress.

Main Results:

• The IL20 line showed significantly greater root elongation under drought conditions compared to Svevo.
• Enhanced root growth in IL20 led to increased water uptake from deeper soil layers, starting from the pseudo-stem stage.
• Improved water uptake correlated with higher gas exchange rates and a substantial increase in grain yield under drought.

Conclusions:

• Re-introducing ancestral alleles from wild emmer wheat can restore a 'lost' mechanism for deeper rooting.
• Deeper rooting profiles are a viable breeding target for enhancing wheat productivity and resilience in water-limited environments.
• This approach holds promise for developing climate-resilient wheat varieties crucial for future food security.