The San Francisco Opera’s Merola Opera Program presents its Schwabacher Summer Concert. Emerging opera performers appear in semi-staged, extended excerpts from “I Pagliacci,” “La Traviata,” “Manon” and “Don Pasquale,” accompanied by a full orchestra.

A free performance is Sunday at 2 p.m. in Yerba Buena Gardens, Mission Street between Third and Fourth streets, San Francisco. Call (415) 543-1718 or visit www.ybgf.org for details. The show will be repeated at 8 p.m. Tuesday in a ticketed event at the intimate Herbst Theatre, 401 Van Ness Ave. Tickets are $40 to $60. Call (415) 864-3330.