George Gershwin, always a staple of summer music festicals in this country, is in more demand than ever this year. To mark the centennial of the composer's birth in 1898, the Cleveland Orchestra presented an all-Gershwin program at Blossom on Saturday (and was slated to repeat it yesterday). Steven Smith, the orchestra's assistant conductor, led the concert.

from his Tin Pan Alley roots, Gershwin found his way into the world of symphonic music, but his orchestral compositions show pride, not embarrassment, in his beginnings. Saturday night's singers made the stylistic crossover with varying degrees of success.

The first set of the three-part program consisted of songs performed by the orchestra, Blossom Festival Chorus and soloists Kishna Davis and Doug LaBrecque.

It was an auspicious Cleveland Orchestra debut for LaBrecque, a tenor who is completely at home in the musical theater genre. Crystalline diction and an easy stage manner added to the effect of his supple voice. Good phrasing helped create a knockout They Can't Take That Away From Me.

LaBrecque sounded simple and charming on Nice Work If You Can Get It too, even though the choral part was nearly unintelligible. Balance was a problem off and on all evening, with the orchestra often overpowering the soloists (despite their use of microphones) and the chorus coming across as utilitarian filler.

Kishna Davis' performance was dominated by a mannered approach that laid on operatic vibrato too thickly. She lacked the clear diction needed to put across a song like By Strauss and here, in particular, she could have used gestures to help deliver the point.

Getting back to fundamentals, including studying the lyrics, would have served her better in these songs and her portion of the third section of the program, excerpts from Porgy and Bess.

In Porgy, the bariton Alvy Powell brought suave tone production and an intelligent, distilled approach to his interpretations.

The young Canadian pianist Stewart Goodyear made his Cleveland Orchestra debut with a performance of the Concerto in F. Tenderness dominated the more obvious technical showmanship in the piece, which Goodyear also easily managed. He allowed himself to sink into the ruminative qualities of the world, with poignant results.

The orchestra accompanied Goodyear attractively, but it was the Cuban Overture that allowed it to be heard in all its glory of blazing brasses and sinuous strings.