FROM HIS HEREDITY experiments in the 19th century, Gregor Mendel concluded that smooth, green peas are dominant over wrinkled yellow ones, implying that three peas in a pod are not necessarily alike. The Currier House Fishbowl productions of three one-act plays support that basic tenet of biology.

The wrinkled, yellow pea in this case is The Kugelmass Episode, based on a short story by Woody Allen and adapted for the stage by Richard Selden. In it, Sidney Kugelmass (Joel Levin), a professor of humanities at the City College of New York with a balding pate and a "chubby cheesecake choked body," tries to add adventure and romance to his life. He enlists help from a magician (Tom Blumenfield) with a contraption that can catapult a person into the novel of his choice and decides to have an affair with Emma Bovary (Troy Segal).

Levin is unconvincing as a middle-aged professor, although he does improve when he berates the magician. Often rushing through lines in a whining tone, Levin fails to employ vocal variety and facial expressions to add humor to his part. Neither does he work to age his voice and stage actions.

The same problems with characterization punctuate Blumenfeld's performance as the magician. His Jewish-German accent, the only distinguishing trait of his character, quickly becomes cumbersome. Although his part is well-written, Blumenfeld's caricatured accent limits his portrayal, reducing the magician to a stereotype.

Ted Wiprud as the zany Professor Marshall Cupris Guigny, on the other hand, performs well, aided by the funniest line in the show. Wiprud in his brief appearance employs a full range of comic devices to lend humor to this part.

Segal, however, is the highlight of the show. Her presence brightens the stage, and her admirable performance, bolstered by a well-sustained accent, effective comic timing and creative vocal and facial variations, adds humor to lines that are not always funny.

That is the major problem with this show--Selden's adaptation is just not all that funny. Allen's sarcastic wit and self-deprecating humor have been lost, to a large degree, in the translation.

Wiprud walks onto the set again in the second play of the evening, The Private Ear, and his tremendous stage presence and energy make the play a success. Written by Peter Shaffer (of Equus fame) to be performed in tandem with The Public Eve--the last play of the trio--Ear shows a man's failure to establish a relationship with a woman he invites to his apartment for dinner.

Wiprud portrays Tchaik, a glorified office boy" in a London import-export firm, with sensitivity and intensity. Not satisfied to play Tchaik, who is apprehensive about the date and generally inexpressive, with typical manifestations of nervousness, Wiprud gives the character depth by exploring his insecurities about relationships with women. Although he falters somewhat, allowing his intensity and energy level to drop when Tchaik is supposed to be drunk, on balance Wiprud turns in a believable, controlled and emotional performance.

Margaret Singer as Doreen plays a dumb blonde with emotional depth. Between giggles and "oohs" she presents a Doreen who is proud of her meager attributes and who is at once disturbed by and sympathetic to Tchaik's brooding introspectiveness.

In contrast to them, Selden, as Tchaik's lascivious and suave friend, does not have a complete grasp of his part. He is neither smooth nor debonnaire enough to be convincing as the sophisticated yet shallow ladies' man who serves as a foil for Tchaik's awkward naivete. Selden does have good stage presence, but his adrenalin falters too often, as does his sporadic British accent.

Peter Ginna's appearance as an eccentric, macaroon-eating detective Julian Christoforou in Eye immediately commands attention. He slinks around the stage, shoes untied, hair greasy and unkempt, slurping yogurt. His initial energy never wanes, and his loony, yet contemplative characterization provides the best humor of the evening.

Michael Kaplan maintains the high energy level and turns in an equally polished performance as Charles Sidley, a London accountant with a three-piece suit and bowler hat, who has hired Christoforou to investigate the suspicious activities of his wife, Belinda. As a man incapable of showing emotion, Charles could be one-dimensional; but Kaplan reveals Charles's inner emotions with an occasional sigh, wince, or tightening of his lips.

Kaplan and Ginna exploit the contrast between their characters for the greatest comic and dramatic effects, creating an interesting and compelling stage relationship. Ginna, however, sometimes rushes through his lines.

Eye is by far the most entertaining of the three shows, marred only by the lackluster performance of Jennifer Christian as Belinda. Many of her lines were inaudible, perhaps because of what sounded like laryngitis, combined with poor diction. Reciting dialogue with little or no emotion, she often acts too immature, pouting when she is confused or upset and picking at her fingernails, a habit that quickly becomes annoying.

Part of Christian's problem with characterization may stem from lack of direction. On the whole, though, directors Selden and Wiprud, with assistance on Ear from Cathy Lo, have done an excellent blocking job, ensuring that the staging is interesting and dynamic. Kugelmass, however, suffers from poor pacing.

THE GREATER PROBLEM with Kugelmass stems from the fact that it simply does not belong with the Shaffer plays. Including it not only makes the evening too long (more than three hours), but also emphasizes the play's own inferiority. Kugelmass appears even more withered and yellow when juxtaposed with the other, better shows. Therefore, unless Kugelmass can be sparked with the same humor, vitality and depth as the Shaffer plays, perhaps it would be best left to succumb to another of biology's theories--survival of the fittest. Ear and Eye are excellent, even with some marginal performances, and deserve to be presented alone.