Opera on the concert stage? It fills many a need

Opera in concert fills many needs. It is often the only way to hear unfamiliar works, or to introduce artists the city's opera houses have not signed up.

Concert operas introduced Montserrat Caballe to America, Maria Callas to New York, Joan Sutherland's Elvira in Bellini's ''I Puritani'' - the list goes on and on.

There have been several groups active in the New York area. Today the most visible is Eve Queler's Opera Orchestra of New York. Thanks to Miss Queler, many works have had an airing that otherwise would have gone unheard in this country, and several of those have been released as recordings on the CBS Masterworks label: Massenet's ''Le Cid''; Puccini's ''Edgar''; Donizetti's ''Gemma di Vergy''; Verdi's ''Aroldo'' (the latter two starring Caballe).

Verdi occupied Miss Queler in the opening performance of her new season. She appeared in ''I Due Foscari,'' Verdi's sixth opera, which is considered much more important in Europe than the United States. Based on a Byron play, it deals with Jacopo Foascari and his father, Francesco, the Doge of Venice. In this revenge tragedy, one Jacopo Loredano has sworn vengeance on the Foscaris for a fatal family feud. By opera's end, he has his revenge.

It is not the most inventive of librettos, but it gives the three major characters many moments to shine, and Verdi here shows more than echoes of his powers-to-come, unlike his even earlier works, which are unsubtle gashes of promise in comparison. It is up to the cast to give it an authentically Verdian ring, with much style, clarity of declamation, nobility of phrasing, and fullness of sung tone.

Carlo Bergonzi's was the most familiar name on the bill. There was a sentimental swell of acclaim upon his entrance, because there was newspaper speculation last spring that the Met had no plans for him in this, his 25th anniversary season there. Because Luciano Pavarotti interceded, the Met has offered to include him in a gala.

There is no one singing today with the authority, the strength and elegance of phrasing, the master's sculpting of phrases. Bergonzi runs into occasional problems, passing ones or serious, in the upper reaches of his music, but these are the things fans and admirers of any artist at this latter stage of a career forgive, particularly when the rest of the performance is so distinguished.

Margarita Castro-Alberty, the Lucrezia, is endowed with a formidable instrument, not always evenly or effectively used. She tackled the copious high notes fearlessly, thrillingly. At the same time, she smudged all her runs, which undermined the strength of her declamation with a very peculiar rubber-spined body language. But she is young and has a potential as formidable as much of the actual singing.

Renato Bruson has become a prominent Verdi baritone since he was last heard at the Met. His voice is rather nasally aggressive and somewhat colorless, giving signs of being a smallish instrument trumped up to sound larger than it actually is. But by the third act, which the baritone must dominate, Bruson sang with heart and tremendous, moving sincerity.