My friend wants to study agriculture science after B.tech. Is it possible ?

I think that there is a fundamental difficulty, because the Natural Sciences provide the basis for the study of Agriculture, especially Botany.

I will suggest to explore & research Agrotechnology MTech courses. That may keep your hold on your degree so well earned.

He can get admission first Bachelor of Science Agri Business & Management this is 4 year degree The candidates should have passed 10+2 or equivalent having passed with Physics, Chemistry, Biology/Math or Agriculture stream from a recognized University/Board with 50% marks in 10+2 (relaxable upto 45