Edward G. Jefferson, chairman of E.I. duPong de Nemour & Co., said today that he is not worried about the possibility that Seagram Co. of Canada could become one of Du Pont's largest shareholders in the aftermath of the Conoco merger battle.

"I start off with the premise that a shareholder is interested in the success of the company," Jefferson said in an interview. "Unitl you have a different reason to be worried, I think these are all paper concerns. They make good reading."

By the time the complex stock-swapping is concluded, Seagram will own a large chunk of Du Pont's stock, perhaps as much as 24 percent. In addition to its holdings of Conoco Inc. stock, Seagram will receive the Conoco shares obtained by Mobil Corp. in its unsuccessful takeover attempt. An undetermined number of Conoco shareholders who acted too late to qualify for Du Pont's cash offer of $98 a share for Conoco stock are offering their stock to Seagram, as well. Seagram can exchange each Conoco share for 1.7 shares of Du Pont stock.

But Jefferson, the scholarly scientist who led Du Pont through the biggest and one of the roughest merger fights ever, appeared undisturbed at the possibility of demands by Seagram for a strong role on Du Pont's board of directors.

"We have a number of large shareholders. We do our best to run the company in a way that benefits them all," he said.

Jefferson would not comment on the possibility that Du Pont family members might use their stock holdings to block Seagram from influencing the future course for Du Pont.

"That's a speculative thing," he said. It isn't clear whether Seagram would be the largest Du Pont shareholder, assuming it buys all the company stock it can. "It depends on the arithmetic, and it would depend on how you look at the Du Pont family." They are really a "collection of investors," not a unified bloc, Jefferson said. "It's clear that Seagram will be very large if the thing unfolds as some people suppose."

But the Du Pont family, whose members hold nine positions on the Du Pont board -- more than one-third -- are said to have between 20 percent and 30 percent of Du Pont stock. The Morning News in Wilmington quoted an unnamed source close to the merger as predicting the family would "rally around the flag" if a confrontation with Seagram develops. f

Jefferson was much more interested in discussing the plans for a new $85 million research center which Du Pont will build near Wilmington, to aid its growing involvement in "life sciences".

At an announcement ceremony today, attended by Gov. Pierre Du Pont IV and other government and business leaders, Jefferson said the Conoco merger was not the only source of excitement within the company.

Du Pont is on the edge of a new scientific horizon -- as it was in the beginning of the 1930s when the company's research in polymer chemistry led to the inventions of nylon and Teflon fluorocarbon resins, Jefferson said.

Du Pont's involvement in research in molecular gentics has opened for way for the development of future products in the areas of medical diagnosis, medicines and therapeutic drugs and plant science that strain the imagination.

Du Pont will spend about $120 million on research and development in life sciences this year, a 33 percent increase over 1980 spending and one-third of its total R&D budget. The new research facility, to be completed in 1983, will accelerate R&D investment substantially, the company said.

Among the goals are modifying food crops to increase absorption of carbon dioxide and thus boost growth and food, production; developing new plants with greater resistance to disease; using sugar, starch and cellulose in plant life, as well as coal, as raw materials for chemical production; and perfecting gene splicing to produce disease-fighting pharmaceuticals.

Jefferson said that Du Pont scientists -- who were the first to purify one important form of interferon -- have made important headway in understanding the molecular structure of this complex protein, a potential weapon against infection and cancer. But the company does not yet know whether interferon will be significant in treating illness.