No, Hyderabad Karnataka Certificate (HKC) is not directly applicable for JEE Main.

There was a national-level engineering entrance test conducted by the National Testing Agency under the name JEE Main. The class 12th as well as age-related eligibility standards are presented to check one's eligibility for the entrance test of JEE Main.

HKC is a regional certificate that may bring in some gains or liabilities at the state level of Karnataka. However, it doesn't have any direct relation with eligibility to appear for a national-level examination like JEE Main.

To be eligible for JEE Main, you must:

You have to pass Class 12 : This shall be along with a minimum required percentage of marks in aggregate with Physics, Chemistry and mathematics as compulsory subjects.

Age Eligibility: The candidate should be at least 17 years old as on the date of examination.

And if these eligibility criteria are fulfilled, then there is no restriction based on regional as well as caste status for gaining JEE Main.