G. D. Searle & Co., which is...

G. D. Searle & Co., which is in the process of being merged with Monsanto, announced that Searle Chairman Donald Rumsfeld next Sunday will relinquish the title of chief executive to John E. Robson, Searle’s president and chief operating officer.

Rumsfeld will remain chairman of the Searle board through the duration of the merger process, which is scheduled to be completed in October. Robson and James M. Denny, Searle’s executive vice president and chief financial officer, will also remain through the transition period.

The structure of management after the merger will be announced later by Monsanto, Searle’s announcement said.