Prophet Adam,according to zalikal kitab was banished from the paradise because he fed from the forbidden fruit.what is this fruit that he ate?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

There is nothing, either in the Quran or in the authentic Sunnah of the Prophet that gives a specific name to the tree which Allaah forbade Aadam and his wife to eat from, and then they ate from it. However, some statements of the Taabi’is (the generation that followed the Companions ) specified what kind of tree it was; Ibn Jareer mentioned this in his Tafseer (interpretation of the Quran) as he said: “It would be correct to say: Allaah, The Almighty, prohibited Aadam and his wife from eating from a specific tree from the trees of Paradise, but they both disobeyed Allaah and ate from it as Allaah described them, but we have no knowledge which tree it was exactly as Allaah did not give us any evidence about this either in the Quran or in the Sunnah, so how can we say which tree it was? Nonetheless, it was said: “It was the wheat tree, and it was said that it was the grape-vine, and it was also said that it was the fig-tree. So, it is possible that it might be one of them. However, if someone knows this, this knowledge does not benefit him, and if he does not know it, his ignorance does not harm him.”

There is no doubt that it is more appropriate for a Muslim to ask about matters that necessitate action and be concerned about what benefits him in his worldly life and his religion.

Allaah Knows best.