Three developers seeking rights to build on downtown Washington Urban renewal and, atop the Metro Center Subway complex, promised yesterday that minority businesses would play a part in their projects.

The minority participation plans drew more attention than architects' drawings as rival developers presented proposals to the Redevelopment Land Agency.

RLA's board, said Vice Chairman Patricia King, will decide by the end of the summer which firm will get an option to build on the land, which runs along the north side of G Street NW, from 10th Street to the Church of the Epiphany, between 13th and 14th Streets.

Proposals for the land were made by representatives of the Oliver T. Carr Co., Western Development Corp., and Landow & Co. Proposals are expected later from Blake Construction Co., and a group interested only in one of the tracts, at the southwest corner of 12th and G Streets.

King questiones the developers repeatedly about their minority hiring practices and how minority firms would participate in the proposed project.

Oliver T. Carr Jr., Cart Co. president, said minority investors would provide about 20 percent of the equity investment in his project. Carr said his builder, George Hyman Construction Co., has done $30 million worth of work with minority subcontractors in the past two years.

Landow's attorney, James Hudson, who is black, said he and a law partner would be 15 percent owners in the Landow development and other minority investors would boost the participation to 25 percent.

Western Development President Herbert Miller was accomplished by James Denson, executive secretary of the District of Columbia Chamber of Commerce, and Joseph Jackson, president of the District of Columbia Development Corp. The two agencies, Miller said, would provide 15 percent minority ownership in the project and would assure that minority merchants operate a similar percentage of the stores proposed for his complex.

The firms have proposed three far different approaches to the land, suggesting projects that range from Landow's $80 million version to a $350 million proposal from Western Development. Carr would not estimate the cost of his proposal, which fell somewhere between the other two in scope.

Both Landow and Miller included apartment buildings in their sketches and both said the housing should be built toward the 11th Street end of the land.

All three developers said a hotel ought to be included in the four-block long development. But Carr emphasized that they iability of a hotel would be directly dependent upon construction of the city's proposed convention center, a block north.

Western Development's proposal focused on retail development, including about 1.2 million square feet of stores in a project of 2.7 million square feet. Miller said a regional shopping mall would be tied in with the present Woodward & Lothrop store and developments on the site now occupied by Woodies' old North Building. He said stores should be built first, to draw people to the neighborhood.

While Western Development's sketches showed decks built across the north-south streets to form a continuous "megastructure," Carr said he believes the project "should definitely not be" a massive building cut off surrounding streets. Landow's drawings showed skywalks above the streets for pedestrians access.

Carr and Landow advocated a series of office buildings along the street, with Landow incorporating basemant level shopping arcades to allow open plazas at street level. Both said the total project should be about 1.8 million square feet, with Carr suggesting about 500,000 square feet of stores and Landow about half that much retail space.

As for architects, Western's big name was I.M. Pei, who designed the new East Wing of the National Gallery of Art. Carr came in with Skidmore Owings & Merrill, a prestigious New York firm. Landow's architects are MOV Inc., a Washington firm, and Byrant & Byrant, a black-owned local planning and design firm.

The developer chosen by RLA will have 120 days to prepare detailed plans for the project, line up financing and tenants and make a final proposal. After negotiations with the RLA board over the price for buying or leasing the land, the developer would be able to begin construction, perhaps as early as next year. Developers said the job would take four to eight years to complete and probably would be built in phases, with the schedule depending on real estate market conditions.