The body will continue to help farmers prepare for events.
Open Farm Sunday is the latest agricultural event to be hit by the coronavirus pandemic.
Organisers Linking Environment and Farming (Leaf) say the event, which was scheduled to take place in June, has been postponed until September 20.
In a statement, Leaf said: “This decision has not been taken lightly and the organisation is fully aware of the implications and disappointment this may cause to host farmers and visitors.
“However, given the challenges that the whole country faces in the coming weeks and months, Leaf has been left with little choice but to postpone the event to later in the year.”
Chief executive Caroline Drummond said the body would continue to help farmers prepare for events.
She said: “We look forward to welcoming the public out to farms at a different and interesting time of year to take pleasure from getting outside and celebrating farming, food and nature.”
Meanwhile, Fettercairn Show, which was due to take place on July 4, has also been cancelled. It follows cancellation of the Fife and Royal Highland Shows earlier this week.
