Hispanic drama on PBS is a cultural landmark - and it's engrossing

Hispanic participation in American drama, with some exceptions here and there in TV and movies, has been of the ''Si, senor, I will saddle up the horse for you'' variety.

Mexicans and Mexican-Americans almost invariably play secondary, semicomic figures in shoot-'em-up westerns. Two major exceptions in past decades which come to mind are the movie ''Viva Zapata'' and the TV movie ''Alhambrista'' (later in theatrical release), but both of these were anomalies.

Now, one of public television's most successful dramatic projects - American Playhouse - is concluding its initial year with a landmark production that may have reverberations in the artistic community - both American and Hispanic.

The Ballad of Gregorio Cortez (PBS, Tuesday, 9-11 p.m.) is a skillful, entertaining, gorgeously photographed film. This dramatization need make no excuses for either its accent or its flavor. A joint project of the National Council of La Raza (NCLR) and Moctesumacq Esparza, it is almost entirely a Hispanic production, dramatizing an actual incident that took place in 1901. A Mexican cowhand in Gonzales, Texas, shot and killed a sheriff in a flurry of misunderstandings on both sides.

While the superficial aspects of the docu-drama focus on the action and suspense as a posse saddles up to track down Cortez, the spellbinding film subtly sizes up the conflict between the Mexican-Texans and the Anglo-Texans in this culture clash.

Although Cortez was finally captured and sentenced to a 50-year term as a lynch mob threatened him, after 12 years in jail he was given a full pardon.

It is the material from which legends are woven. And, in the eyes of some Mexican-Americans, the legend of Gregorio Cortez has become a symbol of the moral dilemma of Hispanics in American society as they try to maintain their cultural identity in a land which they feel tends to reject that culture.

''The Ballard of Gregorio Cortez'' will be shown in theaters in some areas and it will be repeated often on PBS.

The NCLR, an organization based in Washington, D.C., is mainly responsible for the project. It has been attempting to aid the assimilation of Hispanics into the mainstream of American culture by helping them integrate their own heritage into their American life style. NCLR is especially proud that so many Hispanics played active roles in the production. Visual consultant was Ray Villalobos, who also did ''Urban Cowboy.'' The script is by Victor Villasenor and stars Edward James Olmos (who also helped compose the effectively off-beat music score). And although Robert Young, a non-Hispanic, directed (he was also the director of ''Alhambrista''), La Raza regards this as an indication that Hispanics and non-Hispanics can work together in their cause.

I chatted with Guadalupe Saavedra, director of special and international projects for the National Council of La Raza, who informed me that ''Gregorio Cortez'' is the pilot for what NCLR hopes will be a series called ''Somos'' (''We Are'') on national television. There will be dramatizations from all Hispanic literature.

''It is the first time that a Hispanic organization has itself taken the lead in producing such a film,'' he said proudly. ''And we were able to make it for only $1.4 million. That was because it was a labor of commitment for all of us.'' Most of the funding came from the National Endowment for the Humanities, the Corporation for Public Broadcasting, and a consortium of four PBS stations - KCET/Los Angeles, South Carolina ETV, WGBH/Boston, and WNET/New York.

''The Ballard of Gregorio Cortez'' is a solidly entertaining chase film, but more important, it is proof that, given the opportunity and the tools, the ethnic groups that make up the American population are capable of presenting their own stories in the full glory of authenticity.