Dear student, 

No, IISER doesn't offer bachelor's of science in agriculture. For more information, I'm listing the courses they offer -

1)  Integrated B. S-M. S courses in different subjects such as mathematics, biology, chemistry, physics, humanities and lastly earth and climate science. 

2)  Integrated doctoral program in different subjects like biology, chemistry, mathematics and physical science. 

3)   Doctoral programme in different subjects as biology, chemistry, earth and climate sciences, physics, humanities & social sciences and inter-disciplinary. 

And there are many colleges  offering bsc. Agriculture such as PAU, MPKV, IGKV, etc. 

For further detail visit -https://university.careers360.com/articles/top-agricultural-universities-in-india-2016

Hope this helped you. 

Good luck!