Hello...

Candidates must pass 10+2 or equivalent examination in science with atleast 50% marks in biology and in aggregate from a reputed board of the country.

So you can obviously get admission with 81%  in botany.

But some Colleges conduct entrance exam to get admission to B.sc Hons course. For this case you have to pass the test with the eligibility criteria of the colleges.

Hope this will help you.