We are some what sure that you could the seat for your rank, we could not conform because it depends upon the number of students applied for the seats and availability of  the seats in the board it self.

But according to the structure the minimum qualification  required to apply B.Sc in agriculture is 50-60%(depends on institute to institute) in 10+2 with physics, chemistry and biology.  Admission criterion is an entrance test conducted by various institutes which differs from place to place.

So we can say that nothing goes wrong on trying , so you can try for the rank if you belong to open category , or else you can get it easily.