I am of Turkish Descent. I have Turkish Heritage. If it is a very recent relative, like your parent or grandparent, it is also very common to say "My mother is Turkish." or "I am half Turkish." or "I am one quarter Turkish." "My grandfather is Turkish."

I am of Turkish descent I am of Turkish heritage ... or ... I have Turkish heritage

I am of Turkish DESCENT

I am of Turkish descent. I have Turkish heritage. I am of Turkish heritage. Any of these are good.