Millets at the Climate-Nutrition Interface: A Critical Narrative Review of Genetic Improvement, Stress Resilience, Nutritional Security and Sustainable Agriculture

Abstract

Millets are increasingly promoted as climate-smart superfoods, yet this combined label compresses several distinct propositions: that millet crops possess useful stress-adaptive traits, that their grains can improve dietary quality, that modern breeding can strengthen these attributes, and that greater production or consumption will improve food-system sustainability. This critical narrative review evaluates how strongly the literature supports each proposition and where extrapolation exceeds evidence. Literature published from 1 January 2010 to 20 June 2026 was selected from accessible scholarly databases and indexes, with emphasis on peer-reviewed crop genomics, physiology, breeding, food science, human nutrition and food-system studies. Evidence is strongest for the existence of valuable genetic diversity, the expansion of genomic resources in pearl, finger and foxtail millet, context-dependent mechanisms of drought and heat adaptation, and the feasibility of iron biofortification in pearl millet. Human feeding trials show that appropriately biofortified pearl millet can improve iron-related outcomes, but broader claims about glycaemic control, child growth and chronic-disease prevention remain constrained by heterogeneity in species, processing, comparator diets and intervention design. Sustainability evidence indicates that cereal diversification towards less irrigation-dependent crops can improve selected water, nutrient and resilience outcomes, particularly in modelled Indian production systems, but these gains are not automatic: yield stability, processing energy, labour, seed systems, residue value, market access and dietary substitution determine net effects. Genomic advances, including association mapping and pangenomics, have progressed faster than multi-environment validation and delivery in several minor millets. The central implication is that millets are best understood not as a uniform superfood category but as a diverse crop portfolio whose climate and nutrition value depends on genotype-by-environment-by-management-by-processing interactions. Future progress requires breeding targets that jointly measure yield stability and nutrient quality, better field validation of molecular candidates, process-aware nutrition trials, and farm-to-diet sustainability assessment.