Hello aspirant

Horanadu kannadiga means the candidate and either of his/ her parents mother tongue should be kannada, Tulu or kodava.and either of parents's was Domiciled in the state of Karnataka, such candidate ,should have passed his qualifying examination from an University or board or any other Institute located outside Karnataka.

You will be eligible for seat in Karnataka even if you haven't studied for seven years in Karnataka

1) if either of your parents should have studied in Karnataka for at least 7 years or more. You need to prove this by concerned documents like marksheet.

2) You should clear a basic kannada test which will be conducted by KEA . ( Karnataka examination authority) and you should secure Minimum 12 marks out of 50 in this test.

Hence if you have your mother's previous domicile showing that she  was resident of Karnataka for more than 7 years. ( You will have to produce proof  like her  pan card with photo as before marriage she must have different  name ) . So your Horanadu certificate will work.