J.W. Marriott Jr. told shareholders at Marriott Corp.'s annual meeting yesterday that the company will announce in the next few months an effort to extend its business beyond the parts of the lodging and food industry that are Marriott's strength.

The Marriott president's comments were in response to a shareholder, who asked him to explain why the company has been conducting product-development experiments and evaluating "additional segments of the U.S. lodging market," as Marriott disclosed in his address to stockholders.

Company officials later declined to elaborate on the moves that Marriott mentioned.

Noting that Marriott Corp. repurchased about a third of its stock in 1979 and 1980 and financed the acquisitions of Gino's and Host last year, Marriott said the company "will show substantial investment capacity again beginning in 1984.

"It is hard to appreciate the full extent of the company's investment capacity simply by analyzing our balance sheet," Marriott added. He pointed out that the company has an $800 million asset in hotels it owns and another $440 million value in hotel management contracts--together $1 billion in unbooked assets.

The Bethesda company has been expanding and acquiring businesses at a feverish pace, and says it doesn't plan to stop. Most of the growth has been in hotels, with 23,000 rooms added since 1979, 9,000 of those during 1982, and another 25,000 rooms planned in the next three years. By the end of 1985, Marriott will have more than 150 hotels and 75,000 rooms.

Those new rooms are already financed. President Marriott told an overflow crowd of stockholders yesterday at Crystal Gateway Marriott that "most new hotels to be added in the next three years already have been financed and are under construction."

Another shareholder wanted to know when the company planned to split its stock, selling at 68 3/4 bid in the over-the-counter market yesterday. Marriott Corp. stock hasn't split since March 1972. Marriott Jr. responded that management would be considering a split "to keep the price at a level where people can afford to buy it."