Globally powdery mildew (PM) is one of the major diseases of the pea caused by Besides, two other species . and have also been identified to infect the pea plant. To date, three resistant genes, namely , and located on linkage groups VI, III and IV respectively were identified. Studies have shown the gene to be a ' ' homologue and subsequent analysis has identified eleven alleles namely to . Despite reports mentioning the breakdown of gene-mediated PM resistance by and it is still the most widely deployed gene in PM resistance breeding programmes across the world. Several linked DNA markers have been reported in different mapping populations with varying linkage distances and effectiveness, which were used by breeders to develop PM-resistant pea cultivars through marker assisted selection. This review summarizes the genetics of PM resistance and its mechanism, allelic variations of the gene, marker linkage and future strategies to exploit this information for targeted PM resistance breeding in .