The novelty of last night's American Ballet Theatre program at Kennedy Center was "The Rendezvous," a neo-romatic pas de deux by Stephen-Jan Hoff given its company premier on this occasion. It turned out, however, to me by far the least memorable portion of the evening.

Hoff is a Dutch-born dancer who was formerly with ABT. This mildly wistful duet of his is set to a salon piece by Henryk Wieniawski, featuring a plaintive violin solo in a minor key with orchestral backing. Hoff's choreographic treatment, using classroom step combinations, promenades and lifts without the slightest suggestion of individuality, is so utterly conventional that it fades into oblivion as you watch it.

It was danced securely and prettily by Marianna Tcherkassky and Fernando Bujones, but they did far more for the choregraphy than it did for them. Even if one concedes that the idea was merely to give Tcherkassky and Bujones a "vehicle," it's depressing to think that ABT couldn't locate a choreographer with more flair and motivation than this. Composers can't get away with making bad imitations of Rachmaninoff anymore, even in the movies. It's about time similar standards of discrimination began to apply to ballet.

The rest of the program consisted of three ABT repertory staples, all of them splendidly accounted for in the main. The same cast from last week's opening night (except for Richard Schafer replacing Kevin McKenzie), much improved technically and stylistically, gave "Interplay" its rightful quotient of youthful gusto. Lise Houlton was more touching this time in a repeat performance of Tudor's "Lilac Garden," partly through her own reinforced presence, and partly because Marie Johansson, as the groom's old flame, wasn't as overpowering as Martine van Hamel had been.

Best of all was the revived production of De Mille's "Rodeo," looking handsomely spruced up since its last appearance. The square-dance section, as an example, now has lustier, more audible calls and rhythmically sharper stepping and clapping. Jolinda Menendez used her coltish appearance to fine comical advantage in her generally winsome characterization of the Cowgirl. Also on the mark were Kevin McKenzie, Victor Barbee and Michaela Hughes.