Genetic Basis of Water Use Efficiency in Drought-Resilient Crops

Water use efficiency (WUE) is a critical target for improving crop resilience under increasing drought stress. Genetically, WUE is governed by variation in traits such as stomatal conductance, photosynthetic capacity, root architecture and carbon isotope composition. Quantitative trait locus (QTL) mapping and genome-wide association studies have revealed numerous small- and large-effect loci that regulate stomatal aperture, mesophyll conductance and hormonal signalling pathways, notably those involving abscisic acid. Pleiotropic QTLs often influence multiple physiological parameters, linking WUE to growth rate, flowering time and biomass allocation. Advances in high-throughput sequencing and high-density single nucleotide polymorphism arrays have accelerated the discovery of candidate genes, including aquaporins, transcription factors and regulators of chloroplast function. Epistatic interactions between loci further modulate trait expression across developmental stages and environments. Modern breeding strategies combine marker-assisted selection with genomic prediction and, increasingly, genome editing to introduce alleles conferring superior WUE without yield penalty. Integration of physiological phenotyping with multi-omics and environmental data is paving the way for predictive models of performance. Globally, enhancing the genetic basis of WUE supports food security by ensuring stable crop yield under variable water regimes and contributes to sustainable water management in agriculture.

Research from Nature Portfolio

Dynamic QTL analysis in castor bean has elucidated the temporal genetic architecture of photosynthetic traits, including net photosynthetic rate, transpiration and WUE at distinct developmental stages. Over 20 single-locus QTLs were identified for WUE and related traits, with several stable loci detected across multiple stages. Epistatic interactions accounted for a substantial proportion of phenotypic variation, highlighting the importance of non-additive genetic effects. Co-located QTL clusters demonstrated gene pleiotropy, each influencing two to five traits simultaneously. These findings provide a refined map of genetic determinants for photosynthetic efficiency and WUE, offering a robust framework for marker-assisted breeding of drought-resilient castor varieties.

Genetic Basis of Water Use Efficiency in Drought-Resilient Crops publication trend

The graph below shows the total number of articles in genetic basis of water use efficiency in drought-resilient crops across all publications each year (not limited to Nature Index journals).

Technical terms

Quantitative trait locus (QTL): Genomic region associated with variation in a quantitative trait such as water use efficiency.

Water use efficiency (WUE): Ratio of biomass produced or carbon assimilated per unit of water consumed by the plant.

Carbon isotope discrimination (CID): Variation in the ratio of stable carbon isotopes reflecting internal CO₂ concentration and intrinsic WUE.

Candidate gene: Gene within a mapped region that is presumed to influence a specific trait based on function and expression.

Marker-assisted selection (MAS): Breeding approach that uses molecular markers linked to favourable alleles to accelerate cultivar development.

Stomatal conductance (g_s): Measure of the rate of CO₂ uptake and water vapour loss through stomata, influencing photosynthesis and transpiration.

References

1. Dynamic QTL mapping revealed primarily the genetic structure of photosynthetic traits in castor (Ricinus communis L.). Scientific Reports (2023).
2. Mapping QTLs for water-use efficiency reveals the potential candidate genes involved in regulating the trait in apple under drought stress. BMC Plant Biology (2018).
3. The genetic basis of water‐use efficiency and yield in lettuce. BMC Plant Biology (2021).