People with any training or familiarity with horticulture will probably use the word 'cultivar' but otherwise, they will probably say 'variety'.

"Cultivar" is technical. You'd come across it in texts and discussions about horticulture, but is not part of the layperson's active vocabulary. We'd say 'variety', or more informally simply, 'type' or 'sort'.

In everyday parlance, we would say "kind" or "variety." "We are fortunate to live in an area where supermarkets offer a dozen different kinds of apple." If I wanted to ask if an orchard was selling Macintoshes, i.e. a variety whose name is familiar to everybody, I would say "Are Macintoshes in yet?" If I were using a name that might not be instantly recognized as a variety of apple, I would add the word "variety:" "Do you grow the SweeTango variety?" I know the word "cultivar" but I don't think I've ever spoken it aloud in my life.