Peas, as legumes that fix atmospheric nitrogen, play a crucial role in supporting low-input agricultural systems and maintaining healthy soil. They can yield vegetables and grains with less fertilizer when grown as a rotation crop. Darwin and Mendel laid the scientific foundation for contemporary plant breeding, and advancements in genetics, molecular biology, and biotechnology have transformed this multidisciplinary area. Peas are ideally suited to function as a leguminous break crop in a variety of agricultural systems and to satisfy the growing need for high-protein feed for humans and animals worldwide. Crop improvement and the security of the world’s food supply depend on genetic diversity. It is impacted by gene pool diversity and aids in identifying the optimum crop attributes. Molecular markers, morphological trait evaluation, and pedigree data can all be used as the basis for studies on genetic diversity. For more accurate diversity detection, molecular markers are desired, but multimodal approaches are also desirable. Phenotypic diversity within the genus Pisum is promoted by wide hybridization with wild relatives. Studies on genetic diversity in peas have progressed from using restriction-based markers to using PCR-based markers and, more recently, gene sequencing-based research. Genetic diversity has been studied using a variety of marker systems, such as RAPD, AFLP, ISSR, SSR, and SNP markers. These markers can be used to characterize pea accessions for breeding and conservation, as well as to help reconcile discrepancies in taxonomic rank. Consensus maps with improved genome coverage and mapping resolution were produced by combining molecular data from various populations. Desire genes that regulate seed and plant properties have been inserted to create varieties of pea. It has been possible to identify loci linked to agronomic, seed shape, and seed quality variables using genome-wide association studies (GWAS) and SNPs. Farmers and scientists are particularly concerned about the quantity and quality of crop production. Crop productivity is limited by elements such as disease resistance, location-specific cultivars, climatic change, soil properties, drought, water logging, frost, heat, bacteria, and insects. It is critical to assess pea germplasm, choose high-yielding genotypes for enhanced production, and implement breeding programs in order to ensure food security. This will assist in overcoming production limitations and supply mankind with excess food. In this chapter, we have compiled the latest information on genetic resources and their characterization in peas.