Plant diseases pose a significant threat to global food security and sustainability, leading to substantial yield losses in various crop species. Plants employ two primary defense mechanisms to combat pathogen invasion: qualitative resistance, mediated by disease resistance (R) genes, and quantitative resistance, governed by multiple genes known as quantitative disease resistance (QDR) genes. Enhancing crop resistance to pathogens through conventional breeding, marker-assisted breeding (MAB), and transgenic development offers promising strategies to manage disease incidence and minimize yield losses. The identification of genes responsible for both qualitative and quantitative disease resistance plays a crucial role in developing effective disease management strategies.Qualitative resistance is often conferred by major resistance genes encoding cytoplasmic proteins with nucleotide-binding and leucine-rich repeat domains (NLR proteins), which detect pathogen-derived molecules called effectors. Activation of NLR protein-mediated defense responses includes a hypertensive response, rapid localized programmed cell death, ion flux, oxidative burst, lipid peroxidation, and reinforcement of cell walls. On the other hand, quantitative resistance is controlled by multiple quantitative trait loci (QTLs)/genes, providing broad-spectrum resistance that is typically more durable than race-specific resistance. Recent advancements in gene identification have facilitated the successful cloning and validation of genes responsible for quantitative disease resistance in various crop plants. Understanding the plant immune system is crucial, as it involves pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and effector-triggered immunity (ETI). PTI is characterized by the activation of mitogen-activated protein kinases (MAPKs), induction of reactive oxygen species (ROS), callose deposition, and upregulation of pathogenesis-related (PR) genes. Pathogens counteract PTI by delivering effector molecules into plant cells to suppress the host response and create a favorable environment for their survival. ETI, triggered by resistance (R) genes, provides strong resistance against specific pathogens but is often limited in durability due to rapid pathogen evolution. Non-host resistance (NHR) offers a more durable form of resistance and contributes to quantitative resistance. Combining known pattern recognition receptors (PRRs) and NLR R genes in cultivars holds promise for enhancing resistance. Overall, improving crop disease resistance is crucial for ensuring global food security, and a comprehensive understanding of the mechanisms underlying qualitative and quantitative resistance is essential for developing effective strategies.