Financial disclosure forms indicate a $1 million trust fund in which Democratic presidential candidate Michael Dukakis is co-beneficiary sold stock worth up to $65,000 last year from companies with ties to South Africa. The forms, filed with the Federal Election Commission, are consistent with but more detailed than state financial disclosure forms filed by the Massachusetts governor last month. Dukakis gained no income in 1987 from the family trust established by his late father, whose equal beneficiaries are Dukakis and Bates College, the elder Dukakis' alma mater. The trust drew attention last year when similar forms filed with the FEC disclosed that until 1986 it included stock in companies that do business in South Africa. Dukakis has no role in investment decisions of the trust but in 1986, when questioned about its holdings during a gubernatorial re-election campaign, told the bank which controls the account to divest any stock in companies with South African dealings. Stock in 10 such companies was immediately sold. The trust gained between $15,001 and $50,000 last year by selling stock in Unisys Corp., which maintains operations in South Africa. Dukakis campaign spokesman Steven Akey said the trust had owned stock in a company acquired by Unisys last year and sold it because of Unisys' ties to South Africa. The trust also reported capital gains of between $5,001 and $15,000 from the sale of Pepsico Inc. stock. The company maintains indirect ties to South Africa through its Kentucky Fried Chicken subsidiary. Three companies in which the trust has holdings have indirect ties to racially segregated South Africa, largely through distribution agreements and spare parts sales contracts, according to the Washington-based Investor Responsibility Research Center. They are IBM Corp., General Electric Corp. and American Telephone & Telegraph. Akey said the trust's investment policy is to not acquire stock in any company on the Washington group's list of companies with direct dealings in South Africa. Dukakis is also a potential co-beneficiary of another $1 million trust left by his father. But that trust is not considered part of his net worth because Dukakis' 84-year-old mother controls it and could decide to alter arrangements which currently call for that fund to be split by Dukakis and Bates. The FEC forms, which cover the period from Jan. 1, 1987, to March 31, 1988, show Dukakis' principal source of income during that period was $106,310 from his salary as governor. The forms were filed Friday. He and his wife, Kitty, also earned between $1,001 and $2,500 in interest from a savings account that holds between $15,001 and $50,000; between $101 and $1,000 in interest from a smaller bank account in Mrs. Dukakis' name; and between $5,000 and $15,000 in interest from the governor's holdings in the state retirement plan. Mrs. Dukakis also earned $20,000 last year in salary from a Harvard University program that cleans up and preserves public grounds. An investment account in the name of the couple's three children earned between $2,600 and $5,100 last year, according to the FEC forms. The couple also owns a home in suburban Brookline that is worth more than $100,000. Dukakis and his wife, who do not use credit cards, listed no liabilities. The largest investment in the Panos Dukakis trust is a tax-exempt money market fund worth between $100,001 and $250,000. Five of the trust's investments are worth between $50,001 and $100,000: holdings in Maine municipal bonds, a tax-exempt bank trust fund, General Electric, AT&T and Atlantic Richfield Corp.