Context : While the name has been used for all NHL broadcasts on CBC Television (regardless of the time of day), Hockey Night in Canada is primarily associated with its Saturday night NHL broadcasts, a practice originating from Saturday NHL broadcasts that began in 1931 on the CNR Radio network and continued on its successors, and debuting on television beginning in 1952. 
Subject : Hockey Night in Canada 
Relation : production company
The production company responsible for Hockey Night in Canada is what?