L.A. Opera’s ‘Oklahoma!’ Won’t Be Operatic : Stage: The Rodgers and Hammerstein landmark opens Friday at the Chandler Pavilion. ‘The key phrase here is “musical theater,” ’ says its director.

With its simple story line and unlikely opening--a woman churning butter on stage while an offstage voice sings about the beautiful mornin’--it’s hard to think of “Oklahoma!” as a revolutionary stage work.

But when it premiered on Broadway in 1943, this maiden effort of composer Richard Rodgers and lyricist-librettist Oscar Hammerstein II was hailed as the first musical to seamlessly integrate book, songs and dance to tell its story. The songs and Agnes de Mille’s stylish choreography broke custom by defining and advancing the plot rather than serving as diversions. The show ran for more than five years and 2,200 Broadway performances--a record unsurpassed until “My Fair Lady” in 1961--and set the standard for musicals for decades.

Why, then, is this quintessential slice of musical theater being staged by an opera company?

“Because the key phrase here is ‘musical theater,’ ” said Charles Abbott, director of the Los Angeles Music Center Opera production, which opens Friday at the Dorothy Chandler Pavilion for 12 performances, through July 1.

“This is a part of our theater heritage, the only stage form America has contributed. Why shouldn’t opera companies have it in their libraries? For economic reasons, most Broadway shows today don’t have casts this big--44 people and a horse--and certainly touring shows don’t. So only an opera company can have a cast that size.

“ ‘Oklahoma!’ is simple, sophisticated and quietly classy,” he added. “It’s not a step back for opera companies to do it. They’re keeping our heritage alive, and at the same time, it’s good business.”

Starring in this classic about young love in the expanding American West are Jean Stapleton as Aunt Eller and Rodney Gilfrey and Rebecca Eichenberger as the on-again-off-again couple, Curly and Laurey. Also featured are Lara Teeter as Will Parker, Jodi Benson--the voice of Disney’s animated “Little Mermaid”--as Ado Annie, Larry Storch as comic peddler Ali Hakim and Michael Gallup as menacing farmhand Jud Fry.

The L.A. Opera production was initially designed two years ago by Abbott, choreographer Mary Jane Houdina and set designer John Lee Beatty for the Minnesota Opera, with a subsequent staging by Opera Omaha.

“Our approach to staging this hasn’t been different because it’s an opera company,” Abbott noted. “What is different is the casting--we have an interesting marriage of opera singers, musical-theater singers and celebrities with musical-theater and acting backgrounds.

“My task is to lead the opera singers to mute their performances, while also trying to have the musical-theater performers sing as finely as they can. We’ve found that everyone’s nurturing each other--it’s a very enriching experience.”

Stapleton is perhaps best known for her TV work: her eight-year, three-time Emmy-winning run as Edith Bunker on “All in the Family,” and this season’s “Bagdad Cafe” (which has been renewed). But her early career was on the stage and she has appeared in four Broadway musicals, including “Damn Yankees” and “Bells Are Ringing” in the mid-’50s.

Her role in “Oklahoma!” as the strong, independent farm woman has only solo lines rather than songs, but Stapleton quickly dismissed the notion that she was cast because of her celebrity status and audience drawing power.

“Fame is something that’s imposed. It has its advantages, of course, but it’s not reality when it comes to the work,” she said after a rehearsal last week. “That’s not in the script. You’re an ensemble, and you always will be.”

Having performed “Oklahoma!” twice before (the last time in the early ‘80s), Stapleton said, “The only real difference in doing this show with an opera company is that they take the day off before we open. That’s an opera necessity. Otherwise, we’re doing a musical.”

While Stapleton has made minimal performance adjustments, it has been a vastly different story for castmate Gallup, who plays the brooding, dangerous Jud Fry. An L.A. Opera veteran particularly known for his comic buffo roles, the bass-baritone said that his first musical-theater role is “quite a stretch for me, a dramatic, physical and vocal challenge. I can’t get ‘opera,’ ever. I can’t do (big) gestures. In rehearsal, Charles might say, ‘That turn is too operatic. Make it real.’ I have to modulate my voice to sound more like I’m speaking, and since I’m wearing a body mike, I can’t let my voice go because it would fry the system.”

Though Gallup’s song of romantic frustration, “Lonely Room,” is often likened to an aria, he still must adapt to the musical-theater style. “In opera,” he explained, “a lot of questions of tempo, dynamics and emotion will be answered by the music, what the composer has written. In musical theater, you’re freer--you can vary the tempo because you don’t have musical constraints. I may have a whole bunch of eighth-notes”--he sings an excerpt from “Lonely Room”--”but it’s all conversational. There’s no way you could notate exactly what I sang, and I probably wouldn’t do it again in exactly the same way.”

In this new medium, Gallup is also contending with dialogue--in Oklahoma vernacular, no less--dancing and stunts. And, he said, “All the musical-theater people are so much more in shape--they sing, dance, act, even mime. Even though I lost 25 pounds for this role, I still feel chunky.”

While this “Oklahoma!”is very much in the musical-theater tradition, Abbott notes that some elements do differ from the original production. “It was always my intention to cut into the length of the dances,” he said. “In 1943 there was no such thing as television, so entertainment lasted longer. Now, audiences are used to their entertainment happening in a much shorter time span. Mary Jane Houdina and I did our research and knew what each dance had to be about, but she did original choreography, with a nod in style to Agnes de Mille.

“The design is not as lightly balletic,” he added. “They used backdrops, as you would for ballet. John Lee Beatty has used the paintings of Grant Wood as an influence. The colors are brighter and deeper, and the forms are more sumptuous and earthy. Because of that, I think the choreography is earthier.”

Musical theater--not to mention the world in general--has changed a lot in the near half-century since “Oklahoma!” debuted. What does a show about cowboys and farmers, whose major issue was whom to take to a “box” social, have to offer 1990 audiences?

Said Stapleton, “It’s a human story, one of your few basic plots--instead of an evening of marvelous theatrical wizardry--which is rare in musical theater today. You can’t beat the lyricism and the melody. And the dream ballet--what a wonderful way to introduce children to ballet.”

Director Abbott is more succinct. “It’s a damn good score and a damn good book,” he said.