It's exciting news when any young conductor makes a debut with a major ensemble. How generous, then, for the National Symphony Orchestra to place not one but four gifted, hungry artists on the podium of the Kennedy Center Concert Hall Saturday evening.

"Here are four people that you will hear for the first -- but not the last -- time," Leonard Slatkin, the NSO's music director, said in his welcoming remarks. The musicians -- Damon Gupton, Kelly Corcoran, Carolyn Chi-An Kuan and Jordan Brown -- are all participants in the NSO's venturesome National Conducting Institute, a three-week program designed, in Slatkin's words, "to assist conductors with the crucial transition from leading academic, community or part-time orchestras to directing major professional groups."

The chosen conductors spend three weeks attending workshops and rehearsals, meeting with staff members from both the NSO and the American Symphony Orchestra League, and then -- in what Slatkin, with pardonable pride, referred to as a "graduation" -- each lead the orchestra in approximately 20 minutes of music.

If nature abhors a vacuum, then artistic endeavor despises a horse race. I will make no effort to "rank" the four conductors on the basis of a single performance. All had different challenges to face, and all came through what must have been one of the most nerve-racking tests of their lives in pretty good shape. What happens now to these artists depends on them -- their vision, their determination and, of course, the luck of the draw. But there can be no doubt about their talent.

Gupton drew perhaps the toughest assignment of the day, conducting what was not only the first piece on the program (no warmup, for musicians or audience) but also, in many ways, the most challenging, and certainly the greatest. Johannes Brahms's so-called Variations on a Theme by Haydn (the melody is actually taken from an older chorale) is a marvelous motley of musical moods -- simple, songful, fierce, graceful, melancholy, agreeably pompous and exuberantly affirmative by turns.

I admired Gupton's interpretation moment by moment, variation by variation, more than I did as a unified statement. He led the work as an unusually diverse suite of short, disparate movements, after each of which he turned on a dime and headed off in a new direction. Still, many of those directions were fresh and exciting ones, and a second performance will doubtless be more linear.

Corcoran's challenge could hardly have been more different. She led two of Claude Debussy's Three Nocturnes for Orchestra, and especially in the first of these, "Nuages" ("Clouds"), she was called upon to create and sustain a steady, dreamlike mood without lapsing into diffusion or monotony. The Brahms work is all melody and form -- one can imagine it sounding just fine in a piano transcription, for example; whereas the Debussy, with its emphasis on color and nuance, would be rendered meaningless by such an arrangement. Corcoran's exploration of Debussy's soundscapes was sure and sensitive, and the NSO played for her with unusual delicacy.

It was left to Kuan to lead the least familiar music of the evening -- two "Essays for Orchestra" by Samuel Barber, both Slatkin specialties -- and it is to her credit that she not only reconciled the composer's mixture of slightly swoony romanticism with his patrician (yet nevertheless genuine) modernism, but also left the audience cheering. This is music that demands persuasive emotional argument from anybody who would take it on (in blase hands, it sounds merely derivative); Kuan won her case.

Brown then took the stage to conduct what was, in effect, the evening's "encore" -- the "Capriccio Italien" by Peter Ilyich Tchaikovsky, the only "light" music on the program. Problem is, it's really too long for an encore, and it's padded unusually thickly with recitative passages that can seem thuddingly redundant. (The spirit of Rossini, which is always promising to break through, never quite does.) Still, the best tunes in the "Capriccio" are juicy indeed. Brown conducted with vigor and authority; the orchestra played brilliantly for him, and the afternoon closed with a warm ovation.

The concert was dedicated to the memory of Geraldine Clift Ford, a generous and perceptive mentor to many young conductors, who died Feb. 28 at her home in Palm Springs, Calif. Ford was a leading supporter of the National Conducting Institute, and her work will live on.