Single gene heterosis refers to the phenomenon where the offspring of two genetically different parents exhibit superior traits compared to either parent. Synonyms for this term include hybrid vigor, heterogeneity, and outbreeding enhancement. Hybrid vigor refers to the same phenomenon, but is commonly associated with crossbreeding two different breeds or varieties. Heterogeneity, on the other hand, refers to the presence of diverse genetic variants or alleles. Outbreeding enhancement, meanwhile, pertains to the improvement in traits achieved by crossing unrelated individuals. Regardless of the term used, the concept of single gene heterosis is essential in breeding programs that aim to increase productivity or improve quality of crops and livestock.