The pepper, belonging to the genus Capsicum, is one of the oldest and most widely utilized vegetables, condiments, and spices worldwide. Originating from Central and South America, Mexico, and Southwest Asia, it has served diverse purposes, including use as a vegetable, natural colorant, and traditional medicine. As one of the earliest domesticated plants in the Mesoamerican subcontinent, archaeological evidence indicates its consumption dates back to approximately 7500 B.C. Over time, Capsicum has evolved into numerous cultivated varieties exhibiting a spectrum of flavors ranging from mild to hot. Currently, sweet and pungent peppers are primarily employed as vegetables and spices. Genetic resources within the Capsicum genus have been effectively harnessed in modern breeding programs, resulting in the development and commercialization of various sweet and hot pepper cultivars with diverse market applications. These cultivars are bred to express resistance to both biotic and abiotic stresses, often incorporating genes derived from landraces and cultivated species within the genus. This breeding strategy not only aligns with market demands but also enhances crop resilience to environmental challenges. The introgression of genetic material from landraces and cultivated species imparts valuable traits such as resistance to pests, diseases, and adverse environmental conditions. Quantitative trait loci (QTL) represent genomic regions associated with complex traits, including yield, heat tolerance, fruit quality, and disease resistance in pepper. QTL mapping involves identifying associations between measurable phenotypes and genetic markers linked to these traits. In Capsicum breeding, molecular markers are utilized to detect QTLs that influence trait expression. Numerous QTL mapping studies have identified significant loci accounting for a substantial proportion of phenotypic variance within the genus, underscoring the potential of marker-assisted selection to accelerate genetic improvement in pepper breeding programs.