Harnessing Genetic Innovation to Build Climate-Resilient Maize

Fahad Raza

Department of Plant Breeding and Genetics, University of Agriculture Faisalabad, Pakistan

Abstract

Maize (Zea mays L.) is a cornerstone of global food, feed, and industrial systems, yet its productivity is increasingly threatened by climate change, particularly through recurrent heat and drought stresses. These abiotic constraints severely impair photosynthesis, reproductive development, grain filling, and ultimately yield stability, especially in rain-fed agro-ecosystems of the tropics and subtropics. The simultaneous occurrence of heat and drought further exacerbates physiological damage, leading to oxidative stress, pollen sterility, kernel abortion, and deterioration of grain quality. Addressing these challenges requires an integrated, genetics-driven approach to develop climate-resilient maize cultivars. This review synthesizes recent advances (2020–2025) in understanding the physiological, biochemical, genetic, and molecular mechanisms underlying maize tolerance to heat and drought stresses. Key adaptive traits, including stay-green phenotype, deep root architecture, optimized transpiration efficiency, osmotic adjustment, antioxidant defense, heat shock proteins, and membrane stability, are discussed in relation to yield resilience. At the molecular level, the roles of quantitative trait loci, transcription factors, hormonal signaling pathways, epigenetic regulation, and multi-omics approaches are highlighted as critical components of stress adaptation. Furthermore, the review critically evaluates modern breeding innovations such as marker-assisted selection, genomic selection, genome-wide association studies, pan-genomics, and CRISPR/Cas-based genome editing as transformative tools for accelerating the development of climate-smart maize hybrids. The integration of physiological trait phenotyping with genomic prediction models is emphasized as a key strategy to enhance selection accuracy under complex stress environments.