How do you keep them down on the farm? In the case of Birgit Nilsson, born in rural Västra Karup in Skåne, 60 miles north of the Swedish city of Malmö, growing up on her parents’ land in the 1920s was no picnic. Her father didn’t want to lose her, but she was destined for the world’s great stages. Today, the family acres are preserved as a museum commemorating Nilsson’s life and art. This year’s program of master classes prioritizes “home-grown talent.” The grand finale, presented outdoors on the very fields where once young Birgit labored, showcases an international cast in Puccini’s Tosca, one of the diva’s calling cards. The classy Joyce El-Khoury takes the title role, opposite the impassioned Michael Fabiano as Tosca’s lover and the hulking John Lundgren as the villain who comes between them. Pier Giorgio Morandi conducts. —Matthew Gurewitsch