This review constructs an explicit conceptual framework integrating cross-scale defense mechanisms—mechanistically linking molecular signal transduction and post-transcriptional regulation to cellular homeostasis and field-scale yield stability—and spotlight the emerging integration of machine learning-assisted breeding and genomic prediction for the efficient evaluation of superior germplasms.
Abstract
Climate change and the increasing frequency of extreme temperatures pose severe threats to global agricultural productivity, making the breeding of water-efficient crops a critical imperative. Originating from arid regions, foxtail millet serves as an ideal C4 model crop for elucidating plant adaptations to water deficits. Unlike previous reviews that often isolate genomic features from physiological responses, this review constructs an explicit conceptual framework integrating cross-scale defense mechanisms—mechanistically linking molecular signal transduction and post-transcriptional regulation to cellular homeostasis and field-scale yield stability. We first detail the developmental stage-specific physiological penalties of water stress and dissect proactive water-conservation strategies, including stomatal anatomical optimization, root-carbon reallocation, and dynamic rhizosphere remodeling. At the genetic level, we highlight the application of dynamic quantitative trait loci (QTL) mapping, which transcends the static limitations of conventional QTLs by capturing the spatiotemporal evolution of drought-tolerance traits across distinct developmental nodes. To bridge the gap between intrinsic genetic potential and field application, we spotlight the emerging integration of machine learning-assisted breeding and genomic prediction for the efficient evaluation of superior germplasms. Across this framework, several persistent gaps emerge: most drought-responsive genes identified in foxtail millet remain at the level of expression association without functional validation; dynamic QTL analysis remains underutilized relative to its capacity to resolve reproductive-stage drought tolerance; and ML-based genomic prediction, though demonstrated in this species, has not been integrated into operational breeding. Closing these gaps will require connecting high-throughput field phenotyping to genomic selection and deploying functionally validated editing targets in genetic backgrounds relevant to dryland production.
Drought constitutes one of the most pervasive abiotic constraints limiting global crop productivity, with its frequency and intensity projected to increase substantially under ongoing climate change. This narrative review synthesises contemporary evidence on the genetic, physiological, and agronomic dimensions of drought resilience in major food crops, drawing on peer-reviewed literature published primarily between 2000 and 2026. Physiologically, drought impairs stomatal conductance, suppresses photosynthetic carbon assimilation, disturbs osmotic equilibrium, and restricts root-mediated water acquisition, with reproductive stages being disproportionately vulnerable. At the genetic level, the deployment of quantitative trait loci (QTL) mapping, transcription-factor engineering, CRISPR-Cas9 genome editing, and the overexpression of stress-responsive functional genes has opened novel avenues for enhancing tolerance without compromising yield potential. Breeding programmes have increasingly integrated marker-assisted selection (MAS) and genomic selection to accelerate genetic gain, whilst high-throughput phenotyping platforms now enable rapid assessment of drought-adaptive traits at a population scale. Agronomic strategies, including deficit irrigation, conservation tillage, intercropping, and application of plant growth-promoting rhizobacteria (PGPR), provide complementary levers for sustaining productivity under water-limited conditions. Emerging integrative approaches that combine multi-omics, digital precision agriculture, and policy-enabled climate-smart frameworks are highlighted as critical pathways for translating laboratory and field insights into scalable solutions. The review identifies persistent knowledge gaps—including the limited translation of genomic advances to smallholder contexts and the underexplored potential of microbiome engineering—and calls for a convergence of disciplinary expertise, equitable technology transfer, and coherent policy support to achieve drought-resilient food systems globally.
B. Santhosh, V. Sanjivkumar, H. B. Gowda et al.· Journal of Advances in Biolo...· 0 citations
A unified framework that merges mechanistic discovery, microbiome-assisted breeding, soil and water management and systems-level predictive modelling is proposed, essential for developing climate-resilient crops to sustain dryland agriculture.
Muhammad Adil, Isma Gul, Siqi Lu et al.· Plant, Cell and Environment· 0 citations
The agricultural sector faces significant challenges in maintaining crop productivity under environmental stressors such as drought and low nitrogen (LN) availability. Maize (Zea mays L.), a globally important cereal crop, is particularly vulnerable to these adverse conditions. We evaluated morphological data of 21 maize varieties under drought and low nitrogen. Results showed that vegetative traits showed moderate plasticity, while reproductive synchrony was the primary driver of yield stability. Drought stress led to a ~4-fold expansion of the Anthesis-Silking Interval (ASI), increasing from 0.14 to 0.55 days, which contributed to a 27% reduction in grain yield per plant (GYP). The network analysis showed that under drought, traits became fundamentally decoupled. In well-watered conditions, growth and yield formed a highly coordinated hub, but under water deficit the network fragmented — with tip blanking (r = –0.44) and empty kernel rate (r = –0.37) emerging as the key negative regulators. Conversely, the germplasm showed resilience to low nitrogen, with grain yield per plant (GYP) showing no significant difference from control (215 ± 19.3 g vs. 218 ± 21.5 g; P > 0.05). Under low nitrogen, kernel length (−2.1%, P < 0.05) and hundred-kernel weight (−3.2%, P < 0.05) decreased significantly, but total kernels per ear increased by 7.1% (P < 0.05), fully buffering yield through a sink-protected compensation strategy. Utilizing the Stress Tolerance Index (STI), we identified Xinyu 108, Ruipu 909, and Weike 702 as elite, multi-stress resilient varieties, highlighting their potential for cultivation in resource-limited environments. This research offers valuable insights for breeding programs focused on developing resilient maize varieties.
Huaijun Tang, Lei Zhang, Yi Ren et al.· Frontiers in Plant Science· 0 citations
A comprehensive analysis of drought-induced effects across various developmental stages in legumes, detailing the signaling networks that facilitate stress perception and response and analyzing the revolutionary role that high-throughput phenotyping could play in stress assessment and precision breeding.
Andrea Fernández-Gutiérrez, Alvaro F. Rodriguez-Torres, A. Encina et al.· Frontiers in Plant Science· 0 citations
Drought increasingly constrains global wheat production, reducing photosynthetic capacity, accelerating senescence, and shortening grain-filling periods. This review analyses current knowledge on physiological responses (root architecture, reactive oxygen species dynamics, photosystem stability, and abscisic acid signaling) and evaluates agronomic, chemical, nutritional, and genetic countermeasures that aim to protect yield under water deficit. We compare evidence from controlled experiments and field trials to assess which interventions deliver consistent yield benefits, and we highlight trade-offs between water conservation and carbon assimilation. Root traits that access deeper soil moisture, robust antioxidant systems, and balanced hormonal regulation emerge as key biological targets; meanwhile, seed priming, targeted nutrient management, and selected biochemical treatments show promise as near-term, scalable practices. Genetic approaches, including marker-assisted selection and introgression of drought-adaptive alleles, offer longer-term gains but require multi-environment validation. We identify gaps in cross-scale evidence, notably a shortage of multi-location, farmer-level trials that quantify the cost-effectiveness and environmental safety of chemical agents. Finally, we propose an integrated research agenda combining trait-based breeding, optimized nutrient regimes, and pragmatic agronomy to improve wheat resilience to drought. Implementing coordinated strategies across breeding and management is essential to sustain wheat yields as climate variability intensifies.
Rei Waki, Chayara Salsabila, Kiyoka Sakamoto et al.· BIO Web of Conferences· 0 citations