Help me identify this old (1940's?) travelling circus movie with an incredibly racist scene

A long time ago, I was flipping around cable and came across a B/W movie I’d guess was from the 1940’s-50’s. It was about a circus troop traveling by train. The main people were old guy who was the head of the circus, a blond girl, and a hunky guy. At one point the train stops at a field and random groups of workers come out asking what they should do. The old guy tells a group of guys in t-shirts to start setting up the tent, another group to tend to the animals, etc. Then a group of black workers come out and ask what they should do (looking like black caricatures and talking in the stereotypical vernacular of black movie characters). The ringmaster tells them “Well, I saw a farm back there with a whole mess of watermelons. Why don’t you go back there and get you some.” The workers respond with hoots and hollars and lots of 'yassir!'s.

By today’s standards, that scene is incredibly racist. It’s hard to believe they would make movies like that, but I’m sure it was pretty common. I’ve often wondered what that movie was, but I failed to catch the name. Does that scene ring any bells?

Watermelon, mmmmmmmmm! :o

If I had been the one white guy in that group of black workers, I would go back there and get me some, too. Nothing like fresh watermelon.

I like fried chicken, too.