Solo violists are rare birds, and their repertoire is not extensive. Neither is it, by and large, familiar, but there is something about that deep mellow instrument that brings out the best in composers.

For his recital at the Jewish Community Center Saturday, Toby Appel found lovely, seldom-played works by Laderman, Shulman and Kodaly to go along with a couple of old favorites by Bach and Brahms.

Appel, who performs under the auspices of the Young Concert Artists organization, has, in a career that began at the age of 18, made a name for himself in the twin areas of solo and chamber performance. He is a circumspect and careful artist who seems to hold himself at a distance from the emotional heart of the music while exploring, with intense musicality, the nuances of each phrase.

Laderman's "Elegy," written in 1975, was played with great concentration and the sort of technical assurance that made the portamentos and rhythmic configurations sound easy. There was no particular effort here to emphasize the music's lyrical qualities, but they showed through anyway.

Shulman's "Theme and Variations" is an attractive setting, in a rather baroque mold, of a nice modal tune. The music had a cheery, upbeat aura that was welcome in the company of the other somber pieces.

For an adagio by Kodaly, Appel found a new level of warmth, a wider vibrato and a broader bow stroke. The lovely little piece glowed under Appel's understanding touch.

Both the opening Bach G Major Sonata for Viola da Gamba and the concluding sonata by Brahms, more familiar in the guise of a clarinet sonata, were understated--nice, but cool.

Pianist Walter Ponce was marvelous throughout. He tempered his playing to Appel's modest propotions until the Brahms, where he gave himself a little more space.