With Du Pont gone from its garden, DNA Plant hopes for bumper crop. (E.I. du Pont de Nemours and Company Inc.; DNA Plant Technology Corp.)

DNA Plant Technology Corp. has concluded a complex transaction with Du Pont that gives the biotech greater control of its business.

But at least one observer believes the swap may mean that Du Pont has "soured" on the company's key FreshWorld division.

The transaction brings to an end two joint ventures between the companies, as DNA Plant divests itself of one venture and Du Pont of the other. At the same time, the exchange raises Du Pont's overall stake in DNA Plant to 18.5 percent from 7.5 percent.

"We have total control over our destiny," said Robert Serenbetz, president of DNA Plant, an agribusiness biotechnology company, which has its research …