Hey!

Yes, you can join M.Sc. Botany in Mahatma Gandhi university, Kerala after three gap years after your undergraduate in Botany.

You will be required to give reason for your gap years, though. For that, you need to get a declaration given on Rs. 100 non-judicial stamp paper from Tehsildar at the time of admission.This GAP certificate should mention the reason for gap in between your education. If you have been working/interning in some firm, etc. do mention all that clearly.

This certificate need to be mentioned at the time of admission.

Hope it helps!