Breeding for climate-smart vegetables: Genomic strategies for heat, drought, and salinity tolerance

Global climate change poses an urgent threat to vegetable production, as rising temperatures, frequent droughts, and increasing soil salinity disrupt crop growth, reduce yields, and compromise quality. Most vegetable species such as tomato, pepper, cucumber, lettuce, cabbage, spinach, carrot, onion, and eggplant are highly sensitive to these stresses due to their shallow root systems, high water content, and delicate physiology. Developing climate-smart vegetable varieties that can endure heat, water deficit, and salinity has thus become a key breeding priority. This article comprehensively reviews the physiological, biochemical, and molecular mechanisms underlying stress tolerance in vegetables and highlights modern genomic strategies being used to accelerate breeding progress. Core genomic tools whole-genome sequencing, marker-assisted selection (MAS), quantitative trait locus (QTL) mapping, genomic selection (GS), and genome editing (CRISPR/Cas9) are discussed in relation to their applications in identifying, tracking, and manipulating tolerance-related genes. Transcriptomics, phenomics, and multi-omics integration are also examined as transformative approaches linking genotype to phenotype. Through detailed case studies in major vegetable crops, the article summarizes progress in mapping stress-response QTLs, identifying candidate genes (e.g., heat shock proteins, ion transporters, antioxidant enzymes), and developing markers linked to improved physiological traits such as osmotic adjustment, canopy cooling, and ion homeostasis. Overall, genomic-assisted breeding offers a path toward resilient vegetable cultivars capable of maintaining productivity and quality in a changing climate, ensuring food security and sustainability for future generations.