Yes you can apply for Indian administrative examination after passing graduation from open university. for IAS exam you have to pass graduation level degree course.

IAS exam Eligibility Criteria:
Minimum You must complete graduation in any discipline from a well recognized university.

Age limit :
OBC candidate age limit maximum : 33 years.
The candidate must be between 21-30 years of age.
SC/ST have 5 years of age relaxation.

Important dates :
Civil Services Preliminary Exam 2014
Notification Date : 17th May 2014
Last dates for Applications : 16th June 2014
Examination will be held on : 24th August 2014

Civil Services Main Exam 2014
Examination will be held on : 14th December 2014