A novel in vivo shoot regeneration system via callus in woody fruit tree Chinese jujube (Ziziphus jujuba Mill.)

• An in vivo (in planta) shoot regeneration system via callus was first established in woody plant.
• The key factors influencing callus formation and bud regeneration were optimized.
• Chimera-free polyploidy could be created and bloom in the experimental year combining this system with colchicine treatment.
• The novel system took 2–3 years less than in vitro polypoid induction approach.
• A wide range of basic and applied researches would become easier with this system.

In vitro shoot regeneration system via callus is a widely used approach in fruit tree studies. However, it has some obvious limitations, such as high expenses associated with maintaining the sterile conditions, as well as long duration from in vitro culture to field evaluation. After optimization of the key factors including growth regulator, callus induction time and branch diameter, we firstly established a high efficient in vivo callus induction and shoot regeneration system in Chinese jujube, a diploid woody fruit tree. Combining this new system with colchicine induction, pure polyploid could be easily created which could even bloom in the experimental year, at least 2 years earlier compared to the conventional in vitro polypoid induction approach. Furthermore, the new system is much simpler, less costly and more convenient. A wide range of applications in basic and applied researches, such as ploidy manipulation, genetic transformation and mutant induction, would become more efficient with this novel system.