Technical Abstract: Exotic germplasm refers to crop varieties unadapted to a breeder's target environment, and is an important resource for crop improvement. Because genetic diversity within elite cultivars of a crop is limited compared to the variability within the species and its relatives worldwide, genes from exotic germplasm can protect the crop against new biotic and abiotic stresses, and may represent unique alleles for productivity that are absent from elite crop gene pools. Introducing substantial amounts of genetic material from exotic sources into elite crop gene pools while maintaining their productivity is difficult, however. Exotic germplasm incorporation programs require long-term commitments and appropriate breeding strategies, and may be assisted by DNA marker technologies.