*"He constantly punishes himself psychologically. In his eyes **he is inferior in pedigree** to those very confident college graduates against whom he competes."*

The context on the story is the person who the book is talking about is from a poor family and when he grew up he tried to keep up with the rich college graduates by working hard, making big income, and buying expensive things like a $5000 watche.

I don't understand meaning of pedigree in this context.