Dear Charan,
There are some universities/colleges in India which offers PGDM course in Agriculture business management.

1. IIM Lucknow - Indian Institute of Management (IIML)
2. National Institute of Agricultural Extension Management
3. MITCON Institute of Management, pune
4. Indian Institute of Plantation Management, Banglore
5. Vishwa Vishwani Institute of Systems and Management - VVISM

These are some colleges/ Universities has PGDM in Agriculture business management.
I would suggest you to check out MBA in Agriculture business.

i hope this information helps you

all the best