Genetic and Molecular Basis of Processing Traits and Genetic Improvement Progress in Major Fruit Crops

ABSTRACT Fruit processing plays a critical role in reducing postharvest losses, enhancing value addition, and improving the utilization efficiency of horticultural produce. However, most fruit breeding programs have historically prioritized fresh‐market traits such as yield, appearance, shelf life, and disease resistance, whereas traits directly influencing industrial processing performance have received comparatively limited attention. Processing quality is determined by a complex set of physicochemical, biochemical, and genetic factors, including fruit firmness, soluble solids content, sugar–acid balance, color stability, enzymatic browning resistance, flavor retention, and nutritional quality. Recent advances in molecular genetics, genomics, transcriptomics, metabolomics, genomic selection, and genome‐editing technologies have substantially improved understanding of the biological mechanisms governing these traits and have created new opportunities for targeted genetic improvement. This review synthesizes current knowledge on the genetic and molecular basis of processing‐related traits in major fruit crops. Major genes, quantitative trait loci (QTLs), transcription factors, and regulatory networks associated with texture, sugar accumulation, pigment biosynthesis, enzymatic browning, aroma formation, and nutritional quality are discussed. The integration of molecular breeding tools with industrial quality requirements is essential for developing cultivars with enhanced processing suitability, improved product quality, and greater postharvest stability.