The fixture schedule and TV selections will be confirmed next week, with games due to be played on five matchdays between July 16 and 30.
The top two teams from each section and the four best runners-up will join European entrants Celtic, Aberdeen, Hearts and Hibernian in the last 16.
Group A
Dundee
Dumbarton
Peterhead
Forfar Athletic
East Fife
Group B
St Johnstone
Falkirk
Brechin City
Stirling Albion
Elgin City
Group C
Inverness Caley Thistle
Dundee United
Dunfermline Athletic
Arbroath
Cowdenbeath
Group D
Ross County
Raith Rovers
Alloa Athletic
Cove Rangers
Montrose
Group E
Partick Thistle
Queen of the South
Stenhousemuir
Queen's Park
Airdrieonians
Group F
Motherwell
Rangers
Stranraer
East Stirlingshire
Annan Athletic
Group G
Hamilton Accies
St Mirren
Edinburgh City
Livingston
Ayr United