Like so many of his pals, Tucker is a character who doesn't say much for most of the novel, but—when Gaines gives him a chance to speak—he shares his own heart-breaking story.
It's all about his brother Silas, an old-time sharecropper who was convinced that he could work a field faster than any machine. So one day he challenges one of the newly arrived white Cajun folks with his fancy new machine to a race. Silas wins with nothing but his horse and plough. "But," says Tucker, "they wasn't supposed to win. So," Tucker continues "they beat him. They took stalks of cane and they beat him and beat him and beat him. I was there, and I didn't move" (9.133-4).
As you can imagine, standing there and watching his brother get severely beaten left Tucker with some intense feelings of guilt, and so his story is kind of like a confession. Like Mat's story, like Gable's story, and like so many of the other stories we've heard, Tucker's account forces us to take a good, hard look at what racism forces people to suffer through, and what it does to them.