Genomics assisted breeding for mildew resistance in cucumber: from gene discovery to future innovations

Cucumber is an economically important vegetable crop cultivated worldwide, but its productivity is severely affected by destructive foliar diseases particularly powdery mildew and downy mildew. These pathogens cause significant yield and quality losses and the continuous emergence of new races makes disease management increasingly challenging. Conventional approaches including cultural, biological and chemical control often provide limited and short-term effectiveness. Therefore, the development of host plant resistance remains the most sustainable and environmentally sound strategy for long-term disease control. Recent advances in cucumber genomics and molecular breeding have enabled the identification of resistance-associated loci through SNP genotyping, QTL mapping, genome-wide association studies and marker-assisted selection. Furthermore, multi-omics approaches such as transcriptomics, proteomics and metabolomics combined with innovative technologies like CRISPR/Cas-mediated genome editing, genomic selection and speed breeding are transforming resistance breeding. Therefore, by integrating advanced molecular tools with omics-driven insights, this review aims to accelerate genetic gains and facilitate the development of durable, broad-spectrum mildew-resistant cucumber cultivars for sustainable and resilient production systems.