Sony Corp said on Thursday that the chief executive and president of its North American videogame operations, Jack Tretton, who has played a crucial role in increasing its PlayStation business, will step down at the end of March. Sony said in a statement that Tretton, who has led its North American videogames division, Sony Computer Entertainment America, since 2006, resigned following a mutual agreement between them to not renew their contractual relationship. As one of the founding members of the executive team, Tretton played a pivotal role in launching all PlayStation platforms in North America, Sony said in its statement. The divisions executive vice president and chief operating officer, Shawn Layden, will succeed Tretton starting on April 1, Sony said. Tretton has worked with Sony Computer Entertainment America since its inception in 1995.