There are many colleges for M.Sc in Botany. Each college has different criteria for the admission some of the colleges take the admission through its own entrance test & some of the colleges take the admission on the merit list.

Some of the colleges you can prefer:

Delhi University

Banaras Hindu University

LPU jalandhar

Savitribai Phule Pune University 

All above given colleges take the admission through its own entrance. Or you wish to take admission in any particular college then let me know.

Good Luck!