On a recent afternoon, in a brightly lit studio above Times Square, the cast of the opera “Margaret Garner,” which will open New York City Opera’s season on September 11, was rehearsing a slave auction. To the sound of a whip cracking — represented in rehearsal by a hand clap — a line of men opened their mouths to be inspected and twisted their bodies around to show their muscles. The “slave owners” wandered around them, singing, “How much? How much? For pick’nies and mammies and breeders and bucks?”

“Can you believe we did this in this country?” the composer, Richard Danielpour, whispered over the singers. “Isn’t this horrifying?”

“Margaret Garner” is full of equally and more horrifying scenes. The opera, which Mr. Danielpour wrote with the novelist Toni Morrison, is based on the life of a real slave named Margaret Garner, whose story was also the inspiration for Ms. Morrison’s Pulitzer Prize-winning novel, “Beloved.” In 1856 Garner, her husband, and her children escaped from a plantation in Kentucky. When, from their hiding place in a former slave’s house in Ohio, they heard the slave catchers approaching, Garner decided to kill her children rather than see them taken back into slavery. She succeeded in killing her two-year-old daughter before the slave catchers arrived. Garner was subsequently put on trial and convicted — not of murder, but of destruction of property.

There are relatively few operas that explore the African-American experience: among them, George Gershwin’s “Porgy and Bess,” Scott Joplin’s “Treemonisha,” and Anthony Davis’s “X (The Life and Times of Malcolm X)” and “Amistad.” Perhaps partly as a result, opera is not a common entertainment choice among African-Americans. Even at City Opera, known as “the people’s opera” because of its relatively low prices and focus on contemporary work, the audience is overwhelmingly white.

City Opera, however, is making a three-pronged effort to change that. One prong is their Operafor-All festival, now in its third year, which offers $25 tickets for all seats in the theater on three evenings. This year’s festival includes a concert on September 6, showcasing the 2007-2008 season, and performances on September 7 and 8 of “La Bohème” and “Don Giovanni.” City Opera’s executive director, Jane Gullong, said the company has surveyed its Opera-for-All audience, and 20% are people of color, a segment that breaks down to 10% Asian and 10% African-American, Hispanic, and everything else.

The second prong of the effort includes productions such as “Margaret Garner” that address the cultural heritage of groups who aren’t well-represented in the audience. The third prong, which City Opera’s new artistic director, Gérard Mortier, has spoken about in his plans for the company, will be to take productions — most likely not of African-American-themed operas, but of European ones — to venues such as the Apollo Theater in Harlem.

For “Margaret Garner,” City Opera is making a substantial effort to connect with the potential African-American audience. Several months ago, the company hired Donna Walker-Kuhne, an arts marketing specialist with an expertise in building diverse audiences, to handle the marketing push. Ms. Walker-Kuhne has worked for the Public Theater, Dance Theatre of Harlem, and Alvin Ailey American Dance Theater; she did marketing for the Signature Theatre’s season of August Wilson plays and the Broadway productions of “Radio Golf” and “Gem of the Ocean.”

Ms. Walker-Kuhne began the campaign for “Margaret Garner” with a “cultivation event” at the Apollo in June, to which 25 media representatives and leaders of African-American social and professional organizations were invited. The group saw excerpts from the opera and heard members of the cast speak. Afterward, Ms. Walker-Kuhne followed up with the attendees by e-mail, in the hope that they would spread the word to their communities.

Ms. Walker-Kuhne and her staff organized promotional tables for “Margaret Garner” at events such as Black Expo, the Harlem Book Fair, Harlem Week, the African Street Festival, and the Dance Theatre of Harlem Street Fair. She solicited help from the head of the Greater Harlem Chamber of Commerce, Lloyd Williams, and reached out to groups such as the Panhellenics, the New York Coalition of 100 Black Women, and the Urban League. She took out ads in seven newspapers directed at the African-American community, bought two weeks worth of radio spots on the “smooth jazz” station WQCD 101.9 FM, and hired teams to, as she said, “saturate” areas of Harlem, Park Slope, Fort Greene, and Flatbush with promotional materials, leaving a total of 30,000 postcards at bodegas, churches, and colleges.

The sponsor of the production, JPMorgan, is also doing outreach. JPMorgan has invited around 100 music ministers of congregations in the tristate area to a brunch and dress rehearsal in early September, and is organizing other, similar events for nonprofit groups it supports, such as the Executive Leadership Foundation. The president of the JP Morgan Chase Foundation, Kimberly Davis, said that in the last year the foundation has focused on increasing access to arts and culture, in particular opera. Neither Ms. Davis nor Ms. Gullong would specify the amount of JPMorgan’s support for the production, but Ms. Gullong said that JPMorgan will be listed in the program as a “Champion,” a category that refers to donors to City Opera who give more than $250,000.

Ms. Walker-Kuhne said the cost of tickets is not the major barrier keeping African-Americans from the opera or the theater. Rather, she said, “It’s being invited. It’s like anything else: You want to make sure it’s appropriate for you to be there. And the invitation is not an ad in the New York Times.”

African-Americans make their cultural choices, she said, not based on ads or reviews in mainstream papers, but on information from within their communities. “If I see [something about a production] in my local church bulletin, if I see it at my dry cleaner’s, if my girlfriend tells me about it, that translates into an invitation,” Ms. Walker-Kuhne said.

The director of “Margaret Garner,” Tazewell Thompson, said: “The money in the black community goes to the church, to family, to education, and then it goes to concerts.” He said it was largely a matter of people knowing what to expect from their outlay. “If you’re going to hear Stevie Wonder, or Ray Charles, or Patti LaBelle, or Louis Armstrong, or Ella Fitzgerald, you know what you’re getting, [whereas] you’re taking a real gamble with your $100 for ‘The Color Purple.'”

Ms. Gullong said it was too soon to give a report on ticket sales, since single-ticket sales, which she expects to constitute a large portion of sales for this production, have just started.

“Margaret Garner” was a cocommission of the Michigan Opera Theatre, the Cincinnati Opera Company, and the Opera Company of Philadelphia. It began its artistic life in workshops at Princeton University during Toni Morrison’s Atelier — an annual seminar that Ms. Morrison organizes with students and visiting artists — at the Atlantic Center for the Arts in Florida, and at the Michigan Opera Theatre in Detroit. Both Mr. Thompson and the mezzo-soprano who is playing Margaret at City Opera, Tracie Luck, participated in those workshops, although because of scheduling conflicts, Mr. Thompson did not end up directing the premiere production that went to Detroit, Cincinnati, and Philadelphia in 2005 and early 2006.

Mr. Danielpour, the composer, is currently working on a companion opera to “Margaret Garner,” set in the 1960s and about the civil rights movement. “It comes out of my belief that we had two civil wars in this country, rather than just one,” he said.