B.Sc

If you have bio- math combination in 12th, you can explore courses like
B.Sc Biotech from top colleges would be a topmost choice. We can divide the courses option into three type -
1) medical ( pharma, MBBS various paramedical courses)
2) Engineering ( B.Tech traditional courses and B.Tech new type of courses, B.Arch)
3) other courses ( with bio + maths you can do even law). Actually the subject combination give you vast range of courses BBA B.Sc. B.Tech. And many more. You can also go for apptitute test from website like Shortlist. As your subject combination is of vast range. You can do many things but try to do what is demanding in future ( course like data Science would be in great demand) from the top college.

Few reputed college to study B.Sc. Agri. Are -
Punjab Agri. University
ICAR Delhi
GB. Pant University
CCS Ag. University. Hisar
University of Agri. , Bangalore
Tamil Nadu Agri. University
Jayshankar Agri. University, Hyderabad
Jawahar Krisha Vidhalya, Jabalpur
Indra Gandhi Krishi Vidhalya, Raipur
University of Agri. , Dharawad
Acharya Nagarjun Agri University, Guntur
Anand Agri. University, Anand
Raj. Agri University, Bikaner
Kerala Agri. University
Bihar Agri. University
Sardar Patel Agri. University, Meerut
LPU ( private). For detail you can refer ICAR Agri University ranking. Round 1 Cut off rank for University of Agri. Bangalore - 4685. GP PAU - 390-400 ( Closing rank)
Most of the top Agri. University has closing rank within 1000 for B.Sc. Agri. If you can get rank withing 500 -700 it would be more easy to get seat in top agri University. It is different for different category and round, gender, state quota, reserved seats. Best wishes.

Please write about the college name for better response. However the eligibility criteria of M.Sc. Food Science & Nutrition are given below of few Universities for an idea.
1. Eligibility criteria of JD Birla Institute Kolkata : A student seeking admission to the different M.Sc courses must have passed the B.Sc (Hons. ) in anyone from the following with minimum 55% of marks. a) Home Science with specialisation in Food & Nutrition
b) Food & Nutrition
c) Food Science & Nutrition Management
d) Food Science & Processing
e) Clinical Nutrition & Dietetics either
2. Eligibility criteria of Sharda University Noida : Graduation with minimum 55% marks in Home Science/ Nutrition & Dietetics/ Food Science/ Microbiology/ Biochemistry/ Life Science/ BNYS (Naturopathy)/ BAMS (Ayurveda).
3. Eligibility criteria of LPU for M.Sc. (Nutrition and Dietetics) : Pass with 60% aggregate marks in Bachelors of Science Degree (Home Science or Medical or Non-Medical or Bio sciences or Medical Science and Allied Medical or Nutrition and Dietetics or Food Technology or Veterinary Microbiology and Parasitology or Genetic Engineering and Biotechnology or Clinical Chemistry or Public Health and Allied Sciences) or equivalent, subject to qualifying LPUNEST. So from above B.Sc. Hotel management and Food Science students are not eligible for the asked course.