What form of discrimination most directly affected mexican americans?

Highly demanding physical labor for 13+ hours. They were payed the dirt they stood on, children were forced to miss school most of the time because they had to work to support the family. They were also highly expendable, so no medical care was offered, and they were ignored from any complaints. They were basically ignored, and couldn't do anything about it in fear of deportation of their families.

Also, racism and all that affects how they were treated.

But things like the Mexican Repatriation is something to look into. So i definitely suggest it!