The Prague Chamber Orchestra presented a delightfully varied program to a packed house in the Kennedy Center Terrace Theater Saturday night. As an ensemble, the group certainly takes its middle name seriously, playing primarily under the leadership of the concertmaster, with other players taking over as the needs of the music dictate. The result is all one could hope for: clean, assured attacks and phrasing, steady tempos, and well-balanced sonority.

The opening J.C. Bach Sinfonia for Double Orchestra, Op. 18, No. 1, would have benefited from a warmer, more elegant string sound, but the unique wind scoring was handled well, particularly in the lush-sounding middle movement.

Mendelssohn's Piano Concerto No. 1 followed, with Boris Krajny as soloist. The classical nature of the work was apparent throughout, even in the beautifully lyric Andante; the outer movements, though occasionally bordering on the frantic, were marked by marvelously coordinated exchanges between soloist and orchestra. Krajny's encore, Schubert's Impromptu, Op. 90, No. 3, displayed well his expressive capabilities.

In the second half of the program, two serenades by Bohuslav Martinu and Dvorak's "Czech Suite" demonstrated different aspects of the confrontation of nationalistic idioms and classic compositional techniques. The Dvorak style is well known and was superbly represented in this fine performance. But the far less familiar Martinu works were a rare treat, combining French neoclassic wit and scoring innovations with the rhythmic and melodic traits of Czech folk music. Not surprisingly, the orchestra was at its best here, blending skill with native insight.