Please check the source of shoot taken from pedigree trees ..

Dear Iwona

To answer this question, you can provide more details such as the type of explant and the source of the explant taken from the mother plant, the number of subcultures, the duration of the adaptation ...

How often does Magnolia reach its flowering?

One possible answer could be the stressed induced on the plants whilst in vitro. Out in vivo, you would expect the plants to only flow after until they have reached a certain stage of maturity. I would suggest that a plant propgated in vivo is monitored to flowering and use that data for assessment and further experimentation.

Thank you for the suggestion, I will analyze all issues.

Try to reduce the number of subcultures