Heavyweight Larry Holmes, a participant in the suspended U.S. Boxing Championships, is under contract to Don King, the promoter of the boats, it was disclosed yesterday.

However, during the championships Holmes is being managed by the promoter's son, Carl.

There is no question about Holmes being qualified for the tournament. He was ranked among the top heavyweight contenders by the World Boxing Association, the World Boxing Council and Ring magazine. In order to compete, candidates were required to be ranked by the magazine.

A spokesperson for the New York State Athletic Commission said that Holmes' manager is listed as Don King and that the contract expires Aug. 13.

In New York and in several other states, King, as promoter of the tournament, is not eligible to manage a fighter.

Jim Spence of the American Broadcasting Co., which funded the tournament for about $1.5 million, said, "We learned very recently that Don's son is the manager of Holmes as a result of discussions with Don and others.

"ABC does not have copies of the contracts negotiated between Don King Productions and the boxers, except for that of Ike Fluellen of Houston."

King could not be reached for comment.

There is a precedent here. Al Weill, who managed Rocky Marchiano, assigned the boxer's contract to his son, Marty, when the father became the matchmaker for the defunct International Boxing Club.

In another development affecting a figure connected with the tournament the Internal Revenue Service confirmed that James A. Farley Jr., chairman of the New York State Athletic Commission and tournament committee chairman, has outstanding liens totaling $20,239 for back income taxes.

Farley, who suspended himself on Sunday as chairman of the athletic commission pending an investigation by Gov. Hugh Carey over a possible conflict of interest, also faces a judgement by the state for $5,440 in back income taxes.

The federal government contends he owes $19,585 in taxes for the 1973 tax year and $654 for 1974. The state taxes are for 1973 and 1974, including interest and penalties.