Philanthropist Stewart Mott, known for his funding of many fashionable cases from arms controls to government reform, wants Congress to give the domestic sugar industry a federal grant.

It would take the form of price support increases for beet and cane growers that the administration says would cost sugar users $1.2 billion.

"We have to keep beet growers in business as a matter of domestic policy," he said in an interview. "We don't want to be more dependent on imports and the vagaries of the world market."

In this case, General Motors heir was not speaking out purely as a concerned public citizen. Mott is the director of the U.S. Sugar Corp., which is one of a number of a huge food corporations whose fortunes are linked to sugar legislation to be debated in the House Agriculture Committee starting tomorrow.

The U.S. Sugar Corp., which is partly owned by the Mott Foundation, owns 77,000 acres of cane plantations around Lake Okeechobee, Fla. It plans to add 4,560 acres this summer, and would benefit from a proposed bill raising support prices from 13 1/2 cents a pound to 17 cents.

The company's interest in higher prices is anything but unique.

It is shared by such corporate giants as Great Western, which is owned by the late Texas billionaire H.L. Hunt's sons Bunker and Herbert; a number of Hawaiian sugar cane conglomerates , and such makers of high fructose corn sweeteners as Heinz, Anheuser-Busch and A.E. Stalev.

Arrayed against those processors and corporate farming enterprises in opposition to the higher prices are users and cane processors such as Coca Cola; Pillsbury; Nabisco and Amstar, the maker of the Domino sugar.

"There's going to be quite a struggle," said Mike McCloud, until recently staff director and general counsel of the Senate Agriculture Committee and Cane League (which is fighting for higher support prices).

At issue is legislation that affect the structure of the $11-billion-a-year sugar industry, the economies of some 30 foreign sugar exporting countries, the jobs of sugar refinery workers, and the profits of large companies.

Legislation introduced in the Senate by Frank Church (D-Idaho) and cosponsored by 33 of his colleagues would raise the support price to 17 cents a pound and authorize embargoes on imports to maintain that if necessary.

Church maintain that the bill is needed to keep sugar beet growers in business in his native Idaho, other western states and the Red River Valley. Rep. presentatives of corporate beet processors say that the beet growers go, their plants will close and jobs will be lost.

The domestic sugar industry of Florida, Hawaii, Texas and Louisiana are also lobbying hard for the measure.

Rep. E. de la Garza (D-Tex.) of the House Agriculture Committee has introduced a bill similar to Church's. De la Garza represents cane growers in the Rio Grande Valley.

Hawaiian and Louisiana cane growers have powerful allies on the Senate Finance Committee in the persons of Chairman Russell B. Long (D-La.) and Spark M. Matsunaga (D-Hawaii), whose subcommittee on tourism and sugar initiated hearings on the Church bill.

Long chastised an administration witness who proposed keeping the price support at 13 1/2 cents a pound, while adding a .55 cent cash payment to increase the overall income of growers. Industry officials said that the cost of growing cane in Louisiana are the highest in the nation, which means that Long may be unwilling to accept a compromise that could reduce the basic price of Louisiana cane growers.

The Midwest-based corn sweetener industry also seeks higher sugar prices. Plants that make high fructose corn sweeteners (used in soft drinks and ice cream) need higher prices to amortize their investments and pay for planned expansion.

Refiners of raw sugar cane, however, opposed higher supports because these companies rely heavily on foreign imports to keep their plant operating. They fear that the higher domestic price supports would give the home sugar industry a larger share of the market.

Gregg R. Potvin, president of the Cane Sugar Refiners Association, said last week that he expected his opponents to stress the needs of farmers rather than their own corporate interests.

"They always get a couple of dozen little guys . . . to say how hard it is to make growing beets on 12 acres," said Potvin. The largest raw cane refiner in the country is Amstar. Recently, Amstar has diversified into other forms of sugar processing, lessening its heavy dependence on imports.

Also opposing the higher prices are foreign sugar exporting countries , which fear that the higher prices will cause them to lose ground to U.S. beet and sugar and corn sweeteners. So does the Sugar Workers Council of America, whose more than 2,000 members work in plants that keep busy processing imported raw sugar.

This year's lobbying has attracted a number of former government or congressional officials.

In addition to former State Agriculture Committee Aide McCloud, the campaign for higher sugar supports has been joined by Dale Sherwin, recently retired as minority staff counsel of the same committee. McCloud said that Sherwin has registered as a lobbyist for A. E. Staley, one of the leading companies in the corn sweeteners business.

McCloud said that before leaving the committee, he (McCloud) help organize a series of meetings with sugar industry representatives on behalf of Sen. Richard Stone (D-Fla.), chairman of the foreign agriculture subcommittee . . .

"Cane is a $100-milliom-plus business in Florida and you had better believe that Dick Stone care about it," said another lobbyist.

According to McCloud, the purpose of the meetings held by Stone was to seek a concensus from industry representatives on the legislative package.

"The industry wanted to do it in a legitimate arena so it wouldn't be accused of illegal conspiracy to work something out. Stone was host, you might say," said McCloud.

However, a concensus proved unreachable and the cane refiners (who oppose higher supports) eventually dropped out.

A leader of the lobbying effort on behalf of higher supports is Horace Godfrey, a former Department of Agriculture official who represents Florida and Texas cane growers. Godfrey said that his client, the Florida Sugar Cane League, formed the Florida Agricultural Political Education Committee which gave "under $20,000" to federal election campaigns in 1976.

The consulting firm of former Nixon White House aide Williams Timmons has also joined the sugar fray, representing corn sweetener interests in Heinz.