The rising global population has fueled a surge in demand for nutrient-rich vegetables, with Brassica crops being a key focus. Nevertheless, the productivity of these crops is under considerable threat from a range of biotic and abiotic stressors, posing a significant challenge to meeting the world’s increasing food needs. Biotic stresses such as bacterial, viral, fungal pathogens, nematodes, and insect infestations and abiotic factors such as extreme temperatures, drought, and soil salinity significantly reduce both crop quality and quantity. Brassica rapa, a vital species within the Brassicaceae family, holds significant economic and nutritional values but remains highly susceptible to these stresses. Traditional pest and disease management strategies like chemical pesticides and cultural practices are often inefficient and environmentally concerning. Therefore, advanced genomic approaches such as molecular breeding, genomic selection, gene mapping, and genome editing tools like RNAi and CRISPR/Cas9 have emerged as promising alternatives to improve plant resilience. These tools allow the identification and manipulation of key genes responsible for stress tolerance. Genes such as chitinase, glucanase, and cry proteins have been linked to enhanced defense mechanisms in B. rapa, strengthening plant resistance against biotic challenges. The combination of molecular breeding and NGS technologies has enabled quick identification of resistance genes, facilitating resistant cultivar development. This chapter presents a comprehensive examination of the techniques and genomic tools utilized in Brassica breeding programs.