Direct organogenesis from internodal segments of in vitro grown shoots of apple cv. Golden delicious.

A protocol for direct organogenesis from internodal segments of in vitro grown shoots obtained from mature apple cv. Golden delicious trees is presented. Adventitious buds were initiated on Murashige and Skoog medium (1962) containing various combinations of benzylaminopurine (BAP) and 2,3,5-triiodobenzoic acid (TIBA). Low concentration of BAP (4.4 μM) in combination with TIBA (1 μM) gave the best percentage of regeneration. Three repeated cycles of culture and regeneration produced an increase of adventitious budding up to 23%. Although no auxin was used in the organogenic medium, callus was always obtained. The regenerated shoots were micropropagated and rooted. Cytological studies revealed that proliferating buds originated directly from the superficial layers of the internodal explants without an intermediate callus phase.