Champion jockey Glen Boss has made a habit of winning the Doncaster Mile on lightly weighted three-year-olds and will be out to do so again when he takes the ride on promising colt Brandenburg.

Boss has won a record seven Doncasters at Randwick with the past five of those on three-year-old colts or geldings.

The jockey locked in Brandenburg as his ride for Saturday's Group One 1600m feature at Randwick after partnering the colt to fourth in the weight-for-age George Ryder Stakes (1500m) at Rosehill eight days ago.

Brandenburg, who earlier this autumn won the Hobartville Stakes and was a close third in the Randwick Guineas, will drop 6kg from the Ryder to 50kg in the Doncaster.

"Glen had his choice of a few and he got off him after the Ryder and said he wouldn't be on anything else," trainer John Sargent said.

"He'll run well because he can run on the speed or off the speed, it doesn't worry him. He handles the wet as well."

Boss's most recent Doncaster win came last year on Brutal who was coming off a second to Winx in the George Ryder.

His first Doncaster win was on Sprint By in 1996 and he added his second eight years later on star mare Private Steer.

His others have all been three-year-olds - Racing To Win (2006), Haradasun (2007), Triple Honour (2008), Kermadec (2015) and Brutal (2019).

Racing NSW announced on Sunday prize money for this year's Championships had been slashed with the Doncaster reduced from $3 million to $1.5 million in response to the current challenges given the coronavirus crisis.

Champion trainer Chris Waller has won six Doncasters since 2008 and is set to have a host of runners chasing a record equalling seventh win.

New Zealand champion Melody Belle, who was third in the All-Star Mile at Caulfield at her most recent start, was the $6 favourite on Monday ahead of the Waller-trained Shared Ambition at $8 while Brandenburg was at $9.