No one would argue that Scott Joplin’s opera “Treemonisha” packs the dramatic punch of an opera byVerdi, who truly understood theater. The plot about former slaves who run a plantation abandoned by its white owners is slight, and the opera’s message, that education is the key to black advancement, seems disconcertingly naive for an opera dating from 1911.

As flawed masterpieces go, however, “Treemonisha” ranks right up there with the best. Joplin’s piano rags, as the program book for the Collegiate Chorale’s concert performance at Alice Tully Hall on Thursday night observed, “continue to exhilarate and thrill players, listeners, and dancers worldwide.” But Joplin, who died at 49 in 1917, considered “Treemonisha” to be his masterpiece, and hoped the work would make him famous as a “serious” composer. Alas, that never happened, and “Treemonisha” never had a proper performance in Joplin’s lifetime.

Only in the 1970s did audiences wake up to the opera, thanks to several stagings, including a pioneering effort in Atlanta led by a former conductor of the Collegiate Chorale, Robert Shaw. “Treemonisha” is essentially a string of musical numbers, some short, some more extended. What little drama the piece has stems from the brief kidnapping of the eponymous heroine, who is exposed to forest animals and almost thrown into a large wasp’s nest before being rescued by a tenor named Remus.

The simplicity of the plot means that the libretto (by Joplin himself) doesn’t have a lot of plot-advancing text calling for recitative-like passages; what little there is, Joplin treats to a melodically appealing arioso style. Some of the numbers really get under your skin, and for a composer identified with only one type of music – ragtime – there is a fascinating mix of styles.

Part of the genius of “Treemonisha” is that, while its three great ragtime numbers are probably the most infectious of the score, they are cast in special relief by the material around them. For instance, the “real slow drag” in rag style that concludes the opera comes directly after an imposing number in which the chorus members beseech Treemonisha – who has had the advantage of an education under white tutelage – to be their leader. The full-bodied choral writing is spiced with interesting harmonies befitting a Victorian hymn composer. When the “slow drag” follows this grand piece, it supplies release like a big cabaletta.

The other two ragtime pieces, the square dance “We’re Goin’ Around” and the chorus of cotton pickers “Aunt Dinah Has Blowed de Horn,” besides being irresistibly toe-tapping, are typical of the opera’s rich element of local color. So is the church number for the local preacher and chorus, “Good Advice,” which draws on the black spiritual tradition. Some moments recall Stephen Foster and the European musical tradition. More than once, Schubertian triplets support melodies of a Romantic lyrical cut. And Remus’s big number, “Wrong Is Never Right,” which would almost sound at home in a Viennese operetta, reminds us that Joplin wrote waltzes as well as rags. Yes,”Treemonisha” may be a little amateurish, but it is amateurism fired by true inspiration.

The Chorale’s all-black cast was strong. Anita Johnson sang Treemonisha with a bright, robust, slightly tart lyric soprano and showed a takecharge attitude that justified the people’s faith in her as a leader. Robert Mack’s focused, appealingly brassy tenor enlivened “Wrong Is Never Right,” and another tenor, Barron Coleman, more mellow of tone, put across “We’re Goin’ Around” with swagger. Marietta Simpson’s ample mezzo sounded unsteady in the music of Treemonisha’s mother Monisha, but Arthur Woodley sang solidly as her father Ned. James Martin’s crisp diction and colorful characterization were welcome as the “conjuror” Zodzetrick, who encourages the kind of superstition among the people that Treemonisha is determined to root out, and the veteran Terry Cook was an authoritative preacher.

Under Robert Bass’s baton, the performance flowed smoothly with plenty of rhythmic verve. The chorus members, like the soloists in colorful dress, were active and sonorous participants. Captions akin to those in a silent movie were projected on a screen at the back of the stage, although not much of the sung text was included (which might have been useful). Toward the end of the opera, the screen showed pictures of a black doctor and a black astronaut as if to confirm Joplin’s faith in education – although the benefits have come a little late for the people in the opera.