Jackie Robinson's breakthrough

The First. Musical comedy by Joel Siegel, with Martin Charnin, music by Bob Brush, lyrics by Mr. Charnin. Directed by Mr. Charnin. Choreography by Alan Johnson.

Considering the indispensability of black athletes to American sports today, it seems difficult to realize that there were no black players in major league baseball before 1947. Two men were responsible for the historic racial breakthrough whose eventual results extended far beyond the national pastime. One of them was Branch Rickey, the shrewd and innovative president of the Brooklyn Dodgers. The other was the legendary Jackie Robinson. ''The First,'' at the Martin Beck Theater, celebrates that audacious new departure in a winning and imaginative new musical.

With Mrs. Rachel Robinson, the player's widow, as story consultant and technical adviser, it is safe to assume that librettists Joel Siegel and Martin Charnin have been true to the spirit of the Jackie Robinson saga while documenting the salient facts. According to a Playbill note, ''Some characters have been invented and some chronology and situations have been altered.'' But this remains the inspiring account of a baseball owner with the vision to integrate the sport and a player with the prowess and courage to carry through on the vision.

The nature and intensity of Jack Roosevelt Robinson's forthcoming ordeal is spelled out in his first conference with his Dodgers boss-to-be. Jackie tells the courtly and avuncular Rickey that he wants only to be treated fairly. Rickey replies, ''You won't be treated fairly,'' and then goes on to indicate the vicious racism that the young player will be facing - from teammates and Dodgers fans, from the vast majority of club owners, from players on other teams. A berth with the Brooklyn team will not merely test his proven abilities as a ballplayer but will require the self-control not to react openly to insults, indignities, and threats on and off the field.

Events more than confirm Branch Rickey's anticipations. A series of tautly written scenes dramatizes the extreme testing time and the various political and social injustices contributing to it. The comedy that relieves the tension springs from equally authentic sources.

The creators of this biographical musical had no need to fabricate a love story. Jackie Robinson married Rachel Isum the winter before he joined the Dodgers. To Rickey's confidence was added Rachel's sustaining love and support. But according to ''The First,'' it was not until the Dodgers won the 1947 pennant that Jackie achieved the complete breakthrough of camaraderie with his jubilant teammates. It is a thrilling moment on the stage of the Martin Beck.

The relationships of the leading characters to one another are appealingly realized in the performances of the personable David Alan Grier as Jackie, David Huddleston's sagacious Rickey, and beautiful Lonette McKee as Rachel. Court Miller as Robinson's most hostile redneck teammate, Trey Wilson (Leo Durocher), Ray Gill (Clyde Sukeforth), and Clent Bowers (Cool Minnie of the black Kansas City Monarchs) are among the more conspicuous members of a large and lively cast.

The songs by Bob Brush and Mr. Charnin meet the demands and enhance the pleasures of this socially conscious baseball musical - whether the need is for jazzy take-me-out-to-the-ball-game ditties, romantic ballads, or character songs. Rickey and Durocher give some recalcitrant players a lesson in management and poker in the deftly ironic ''Brooklyn Dodgers Strike.'' The infectious musical performance owes much to Luther Henderson's orchestrations, Joyce Brown's vocal arrangements, and Mark Hummel's conducting. Alan Johnson has choreographed the brief but crucial game sequences by using just a few players to suggest a whole action - an economically effective solution.

From the bold silhouettes of the opening scene to the series climax, the show has been staged with imagination and wit by Mr. Charnin. Marc B. Weiss's airy lighting of the atmospheric David Chapman sets as well as the Carrie Robbins period costumes all contribute visually to the celebration of a momentous event and its pivotal figure. You don't have to be a baseball fan to root for ''The First.''A Soldier's Play. Tragic drama by Charles Fuller. Directed by Douglas Turner Ward.Once more playwright Charles Fuller has chosen the formerly segregated United States Army as the milieu for a study of racism's tragic destructiveness. But whereas ''The Brownsville Raid'' of several seasons ago dramatized an actual World War I incident of mass racial injustice, ''A Soldier's Play'' deals suspensefully with a fictitious episode from World War II.The scene of the opening work in the Negro Ensemble Company's 15th season is Fort Neal, La., in 1944. A black master sergeant (Adolph Caesar) has been shot and killed while staggering back to his quarters from a drunken spree at a noncommissioned officers' club. Local Ku Klux Klansmen are naturally suspected. Investigation discloses that Sergeant Waters had an encounter with two white officers on the night he was killed.The investigation is the centerpiece of ''A Soldier's Play.'' It appears initially that Mr. Fuller is going to focus primarily on the problems Capt. Richard Davenport (Charles Brown) will be facing as a black officer whose difficult assignment will include interrogating hostile and uncooperative whites. First of all, he must contend with the Fort Neal command's legal officer, Capt. Charles Taylor (Peter Friedman), a West Pointer with built-in racial prejudices.Mr. Fuller's approach is, however, more complex and interesting. Narrow-minded though Taylor may be, he nevertheless believes in justice - an outcome he considers impossible if the case is handled by a black officer. Davenport persists. But instead of the suspected Klan involvement, he discovers the hostility Waters had provoked among the men who served under him.A series of interviews incorporating flashback reenactments reveal that Waters was a World War I volunteer for whom the Army had provided a position of relative authority impossible to a black man in the civilian world. As a spit-and-polish NCO determined to please his superiors, Waters had ridden roughshod over his subordinates. His particular victim was Pvt. C. J. Memphis (Larry Riley). An innocent and unoffending youngster from Mississippi, Memphis symbolizes everything about Deep South blacks that Waters, the urban Northerner, detests. (Waters's treatment of C. J. contains a conscious allusion to the relationship between the evil Claggart and the innocent, doomed hero of Melville's ''Billy Budd.'')Mr. Fuller's carefully written, tautly dramatic scenes are filled with racial-psychological insights. While coming squarely to grips with the disturbing human forces at work in this particular soldiers' world, the playwright doesn't neglect character comedy or the raunchy, uninhibited mess of black GI barracks talk. Finally, Davenport's parting verbal shot at Taylor constitutes a confident challenge spoken with humor.The pace and intensity of the melodramatic plot are admirably sustained in the performance staged by Douglas Turner Ward at Theater Four. As the young guitar-playing blues singer from Mississippi, Mr. Riley makes it abundantly clear how C. J.'s very inoffensiveness riles the belligerently determined yet insecure Waters. To the older man, C. J. and his like threaten a hard-won and still vulnerable status.Serving as both focal character and sometime narrator, Mr. Brown presents the visiting investigator as an officer of courage and a gentleman of dignity. Mr. Friedman's Captain Taylor embodies the attitudes of a middle-class white whose prejudice conflicts with his intelligence. Denzel Washington and Steven Jones are among the more prominent members of the excellent Negro Ensemble Company cast.Felix E. Cochren's setting, lighted by Allen Lee Hughes, suggests the nondescript drabness of an Army premises. Credit Judy Dearing and Uncle Sam for the military fatigues and dress uniforms.