create list for dropdown with value from relationed table

My model Product return something like this

• id = 1
• name = Product Name
• category_id = 101
• category = array
  • id = 101
  • name = electronics

and I need to use lists() to create something like this:

lists("category.name", "id")

but it looks that this is impossible. How to create list for dropdown like this:

1 = electronics
2 = furniture
3 = cars
...

thanks a lot

via Chebli Mohamed