It was a long and wonderful afternoon at the Filene Center yesterday, as the Wolf Trap Opera Training Program came to a close with a show billed as "Future Stars in Concert." If this show is any indication, the future of opera here does not look bad at all.

Not all the singers were ready for the demands of the masterpieces of opera. But ready or not, most showed off that quality that has become the trademark of the American singing actor: presence and commitment on stage, the feeling that there is much more to opera than putting notes together. These young artists entertained as they sang, and some emerged as audience favorites.

Soprano Beverly Hoch got the loudest ovation for her daring "Bell Song" from "Lakme." There were silver chimes in the final runs of this treacherous aria, her perfectly focused light voice creating the illusion of size while maintaining its youthful sound.

There were some outstanding baritones, beginning with Peter Lightfoot, whose "Largo al factotum" from "The Barber of Seville" demonstrated that it is possible for a man to execute coloratura passages at breakneck speed without cheating. Roger Wangerin is a true Verdi baritone with a voice as rich as chocolate; his "Eri tu" soared. With a smaller instrument, Stephen Owen brought pathos and rage to Verdi's "Ella giammai m'amo!" from Don Carlo.

Two of the singers chose execrable English translations for their moments in the spotlight, and their talents were hard to judge as a result. Those who chose to sing numbers from opera originally written in English, however, gave a beautiful bit of variety to the program. Baritone Paul Milkie was warm, if somewhat covered, in an aria from Moore's "The Ballad of Baby Doe." Sandra Ruggles, a soprano to watch, sang plaintively Menotti's lovely "Steal Me, Sweet Theif" from "The Old Maid and the Thief." Even that most awful of kitsch bombs, Floyd's "The Trees and the Mountains," from "Susannah," emerged as a beautiful scene as sung by Kathryn Karassik.

The fun at Wolf Trap began before the show, when Michael Hume and Mary Ann Rayment gave a "History of Musical Theater" through song and talk. Hume's patter as he transformed himself from Curly the cowboy from "Oklahoma" to Motti the taylor from "Fiddler on the Roof" and others, created an entertaining gem, to be repeated in the Meadow Tent on Sept. 4.