Salinity Stress in Millets: Implications for Food Security and Climate Resilience

Abstract

Salinity stress is a major abiotic constraint limiting crop productivity, particularly in arid and semi-arid regions where altered precipitation patterns and high evapotranspiration accelerate soil salinisation. Millets, including pearl millet, finger millet, and foxtail millet, are recognised as climate-resilient crops with remarkable adaptability to marginal environments. Despite their inherent tolerance, salinity adversely affects their growth, germination, physiological functions, and yield through osmotic stress, ionic toxicity, and oxidative damage. This review synthesises current knowledge on the physiological, biochemical, and molecular mechanisms underlying salinity tolerance in millets, highlighting the role of osmolyte accumulation, antioxidant defence systems, ion homeostasis, and stress-responsive signalling pathways such as the SOS pathway. Recent advances in genomics, transcriptomics, and molecular breeding have facilitated the identification of key genes and quantitative trait loci associated with salinity tolerance. Biotechnological approaches, including transgenic strategies, gene pyramiding, and CRISPR/Cas-mediated genome editing, offer promising avenues for enhancing stress tolerance in millet crops. However, challenges such as limited genomic resources and transformation efficiency, particularly in finger millet, restrict the widespread application of these technologies. In addition to genetic improvement, agronomic interventions such as efficient irrigation, nutrient management, and the application of organic amendments (e.g., biochar, compost, and manure) play a crucial role in mitigating salinity stress and improving soil health. The integration of conventional breeding, modern biotechnological tools, and sustainable agronomic practices is essential for developing salinity-resilient millet cultivars. Overall, millets hold significant potential for ensuring food and nutritional security under saline and climate-stressed environments. Future research should focus on multi-disciplinary approaches, including high-throughput phenotyping, genome sequencing, and precision breeding, to accelerate the development of stress-tolerant and high-yielding millet varieties.