Then is jain potato allowed to eat which grows iverground?
In Jainism, eating root vegetables that grow underground is generally avoided. Potatoes are a tuber and are considered a root vegetable, so they are typically not allowed for strict Jain practice. This applies to both Digambar and Shwetambar traditions, though individual communities may have slight local variations.
If you want a precise ruling for your community, check with your local Jain monk or community leader.