A somatic mutation arising in a bud and producing a genetically different shoot. Bud sports includes changes due to gene mutation, somatic reduction, chromosome deletion or polyploidy.
A bud sport is a part of a plant or tree, for example, a leaf, shoot or flower, which due to a genetic mutation clearly differs from the rest of the plant, and which can also be grafted to grow new plants which retain this genetic difference as a new cultivar.