The history of mapping the apple genome

This review summarises the research projects that have been conducted with the goal of mapping the apple (Malus × domestica) genome. The generation of apple linkage and physical maps, which was started at the end of the 20th century by many scientific teams, has resulted in rich data useful for further fundamental and applied studies. The mapping efforts mainly contained the choice of mapping populations as well as the choice of types and number of markers. Over the years, scientists have achieved major successes and faced major obstacles. Many economically important traits have been mapped in the apple genome, which has a total length of 2000 cM. The recently published integrated genetic and physical maps summarise the data and will be helpful to modern breeding programs, with a special focus on resistance to various diseases, as well as on fruit quality and other desired apple traits.