The president of the Quaker Oats Co. yesterday threw his support behind a "full inquiry" by the Federal Trade Commission into television advertising aimed at children as well as programming practices themselves.

In a meeting of cereal manufacturers with members of the FTC. Quaker's Oats' Kenneth Mason said he didn't think an agency review of the nature and effects of advertising and sugared products aimed at children would support the negative conclusions some want the FTC to draw about cereal advertising.

But such an inquiry would raise questions that need to be answered on "the effect of commercial television on the intellectual and emotional health of children," Mason said.

"The Quaker Oats Co. has no desire to maintain the status quo in television advertising to children," he said. "Indeed, we do not believe any reasonable person can view a typical 8 to 12 noon Saturday morning period on any of the major television networks and fail to recognize the need for fundamental change in the way our society is using its most powerful and prevasive medium of communication to entertain and enlighten the very young."

The FTC is considering petitions from Action for Children's Television and the Center for Science in the Public Interest which raise question about television advertising directed toward children in general and sugar advertising specifically.

In opening the meeting yesterday, FTC Chairman Michael Pertschuk said he believed the petitions raised tow general issues which concern him: the propriety of television advertising directed to three, four, and five-year-olds, and the cumulative impact of advertising for highly sugared products on the "immature child."

Representatives of both Kellogg's and General Mills told the commission in no uncertain terms they thought aiming advertising at children is appropriate and advertising pre-sweetened breakfast cereals is beneficial because they contribute to good nutrition, Dr. Gary E. Costley, director of nutrition for Kellogg's, contended that sweetened cereal accounts for only 2 per cent of the sugar Americans consume and does not contribute to dental decay.

Arthur Schulze, group vice president of General Mills, argued that there was no evidence that cereals are harmful. Breadfast is an important meal that children are inclined to eat when they like a cereal, he suggested.

He defended beaming cereal advertising at children so that they can"participate in the decision to purchase a given product. "No useful purpose is served when a parant purchases a cereal children won't and don't eat," he argued.

"Why is it not possible to direct these message to the parent . . . rather than take your case directly to the child?" Pertschuk asked.

"We do have other ads, but the user is important," Schulze contended.

The presentations by the cereal companies included slides on the nutritional content of cereals as well as a number of current television commercials, including several by Kellogg's that concentrate on the value of good breakfasts.