The shops, operating under the Morrisons brand, will open by the end of the year and will allow the grocer to supply branded and own-brand food to the forecourts.
Last month the supermarket sold its existing 140 M local high street convenience stores for £25 million to retail entrepreneur Mike Greene, but said it would look at other opportunities in the growing convenience market.
Chief executive David Potts said: “As we said at our recent interim results, we want to consider new opportunities to serve customers better in the convenience market where the capital commitment is low and the Morrisons resourcing is light-touch.
“This pilot in Motor Fuel Group filling stations will allow us to trial one opportunity in this growing channel.”
MFG is the second-largest independent forecourt operator in the UK, with 373 stations operating under the BP, Shell, Texaco and JET fuel brands.
Locke, who became one of Scotland’s richest men when he sold oil and gas services business Abbot seven years ago, is the chairman of MFG, which was bought by Clayton, Dubilier & Rice from fellow private equity firm Patron Capital in a £500m a deal in June.