Dear aspirant,

                    IISc takes admission on basis of your kvpy score or your jee mains rakings . So if youhave opted for the jee mains option while filling the form for iisc you will be able to get admission if you clear the cut off. As for IISER they also take admission on the basis of your mains ranking . they also confuct there own entrance test you can select which option suits you the best . 

So if you meet the cut off for IIsc and iiser then you will get admission on basis of your jee mains score.

All the best