When American Ballet Theatre makes its Wolf Trap debut this week, the John Taras touch will be much in the foreground. Taras, appointed last year as ABT's associate director, has inserted new details in the staging of two of the company's major offerings for the week-long engagement -- George Balanchine's "Theme and Variations" and the perennially popular "Giselle."

In a recent phone conversation, Taras, now part of a ruling triumvirate along with artistic director Mikhail Baryshnikov and artistic associate Sir Kenneth MacMillan, talked about his role within the artistic management of ABT, as well as the Wolf Trap programs.

"My role is certainly more defined than when I started. But it's still shifting around quite a bit. One reason has been that I've been with the company more often than anyone else this past year. Misha Baryshnikov was away more than he will be this coming year, and Sir Kenneth of course has a large commitment to the Royal Ballet. The result was that I was more constantly around the dancers. Misha intends to be running things more steadily for the '85-'86 season; even if he isn't dancing -- he's recuperating from this recent knee surgery, you know -- he'll be there. And that's very important for the company. The dancers look up to him and value his presence.

"The fact is when decisions are to be made, the three of us discuss things with each other. I don't want to give a wrong impression -- Misha is definitely the head of the company, the last word is his. But he's very good about consulting with us. He doesn't just go off on his own and decree something, and then we learn about it through the newspapers."

Taras, 66, is no newcomer to this kind of job. "I've run companies before, it's something I feel I can do," as he puts it. Among the companies he's served as director or ballet master in the past have been the Paris Opera Ballet, the Ballet of the Deutsches Opera in West Berlin, and, from 1948 to 1959, The Grand Ballet du Marquis de Cuevas in Monte Carlo. More recently, he spent about two decades as ballet master and close associate of Balanchine at the New York City Ballet, a position ended only by his ABT appointment. His Balanchine association goes back even further; Taras began his career as a dancer with Balanchine's American Ballet Caravan in 1940.

Taras also goes way back with ABT, having danced with the company from 1942 through 1946. It was during this period that he launched a prolific career as a choreographer, creating his first ballet, "Graziana," for Ballet Theatre (as ABT was then known) in 1945. Among his many other works are "The Minotaur," to an Elliott Carter score, for Ballet Society, 1947; "Designs With Strings," to Tchaikovsky, created for the Metropolitan Opera Ballet in 1948 but staged by numerous troupes internationally since then; and "Piege de Lumie re," for the Cuevas company in 1952, revived in 1964 by NYCB. Today's public is probably most familiar with the colorful "Firebird" Taras mounted for the Dance Theatre of Harlem several years ago, seen on national telecasts in the "Kennedy Center Tonight" series.

Taras' long experience with both of the leading classical ballet troupes of this country -- ABT and NYCB -- gives him a unique perspective on the differences and similarities between the companies.

"The differences in training of the dancers," he says, "aren't as great as people tend to think. If you take a close look at NYCB, you find a lot of the dancers were not trained at the company's school, the School of American Ballet, though it's true most of them have had a similar kind of training. If the training of ABT dancers is less uniform -- they come from all over -- many still were either products of SAB, or studied with teachers who came from City Ballet.

"The main difference in working with dancers from the two companies stems from the fact that ABT is a touring company that spends most of its time on the road. NYCB is fortunate enough to have a permanent home where it performs 22 to 24 weeks a year . . . ABT, on the other hand, is traveling more often than not.

"But as a result, ABT is a much closer company than NYCB, much more a 'family' company, it seems to me. Mainly this is because people live together so much of the time. With a company like NYCB, you do your performance and go home, more or less. On the road, the ABT dancers eat at the same restaurants, sleep in the same hotels.

"The same is true even in the matter of taking class. In New York, dancers tend to go off to their different gurus, to get the personal 'therapy' they like -- they take classes in many different studios, with different teachers. When you're on the road touring, as in the case of ABT, you take company class. In this sense, ABT is a more unified company."

Company atmosphere is also a factor, Taras thinks. "Dancers are dancers," he says, "working with those from this company or that is really not all that different. But I have the sense that ABT dancers try a little bit harder, perhaps, because there's more competition. In NYCB one sometimes felt that once a dancer made it from the school into the company, that was it -- they were very talented in school, but once they got into the company they settled into a 'job,' or stopped really working at it. That's not true at ABT, where people are constantly having to prove themselves anew."

The "Giselle," which returns to the ABT repertoire in five performances Wednesday through Saturday evenings, with a matinee on Friday, is not a "new production," as announced in early Wolf Trap publicity. Some changes have been introduced -- mainly by Taras -- since the company last performed the ballet, but the sets and costumes remain the same.

Before Baryshnikov became ABT's artistic director, the company's version of the classic was one originally staged by England's David Blair in 1968 -- the premiere took place in Washington at the Carter Barron Amphitheatre on the Fourth of July. In recent seasons, Baryshnikov has somewhat reshaped the choreography in accord with his own heritage from Russia's Kirov Ballet, with its links to Marius Petipa, whose revisions of the 1841 Paris original became the basis of most western productions.

Taras, though, had grown up with an earlier ABT "Giselle," the company's first version, staged by Anton Dolin in 1940. Dolin, in turn, had learned "Giselle" in England in 1934 from Nicholas Sergeyev, who had based his production on choreographic notations he'd taken with him when he emigrated from Russia. Such is the complex background of Taras' recent emendations.

"The 'Giselle' the company has now," Taras says, "is basically the version from the Kirov, and it's very different from the one by Dolin I knew from early Ballet Theatre days. In particular, there's very little dancing for the male ensemble; in the version I knew the men were all over the place, and I've tried to bring them back a little. Now the men will have a big dance during the celebration before Giselle is crowned queen of the harvest in Act I. I've also redone the 'Peasant Pas de Deux' as a pas de quatre for two couples, and we're doing it at the beginning of the act, even before Giselle's first variation, on the theory that once you've started your story, and got Bathilde and everyone else on stage, you don't want to interrupt the narrative. I may change my mind once it's all put together, but for now that's how it goes."

Taras has also made minor changes in "Theme and Variations," which opens the mixed repertory bill Monday and Tuesday evenings -- a work Balanchine originally choreographed for Ballet Theatre in 1947. It wasn't until 1970 that it was staged for NYCB (by Michael Lland, an ABT ballet master), at which time Balanchine altered it to suit his own dancers of the era, including principals Gelsey Kirkland and Edward Villella. "In some places," Taras says, "I've made the ABT version more like the NYCB, where I felt it was a more natural, more logical way to do things. But I also think some parts are more beautiful in the ABT version, which was, after all, the first one -- for example, the adagio for the eight women and the ballerina, which is much more interesting in the ABT version."

Taras is also presently working on a new original ballet, a "Francesca da Rimini" using the Tchaikovsky score and the story of doomed lovers drawn from Dante. "I'm doing this as a ballet for Cynthia Gregory and Fernando Bujones," he says. "It will certainly be completed by the time the company returns to Washington next spring."

Also on the repertory program with "Theme and Variations" are Fokine's "Les Sylphides," and the "Raymonda Divertissements" staged by Baryshnikov. Additionally, Monday evening's program will include Jerome Robbins' "Other Dances"; the "Don Quixote" pas de deux will replace it Tuesday evening. Friday and Saturday nights, "Giselle" will be preceded by the "Kingdom of the Shades" scene from "La Bayadere."