Micropropagation of apple--a review.

Micropropagation of apple has played an important role in the production of healthy, disease-free plants and in the rapid multiplication of scions and rootstocks with desirable traits. During the last few decades, in apple, many reliable methods have been developed for both rootstocks and scions from a practical, commercial point of view. Successful micropropagation of apple using pre-existing meristems (culture of apical buds or nodal segments) is influenced by several internal and external factors including ex vitro (e.g. genotype and physiological state) and in vitro conditions (e.g., media constituents and light). Specific requirements during stages of micropropagation, such as the establishment of in vitro cultures, shoot multiplication, rooting of microshoots and acclimatization are summarized in this review. New approaches for increasing shoot multiplication and rooting for apple and current use of micropropagated plantlets as tools in basic and applied research are also discussed.