University of Missouri wrestling coach Brian Smith announced Monday morning  that Scott Barker, rated by Intermat as the nation's number-one high school  recruit at 189 lbs., will be added to the line-up of incoming freshmen this fall.  Barker had previously signed a national letter of intent to wrestle  at the University of Northern Iowa, but was released by school officials  after he indicated his desire to attend MU.    "We're very excited to have Scott," said MU head coach Brian Smith.  "He's a  great addition to an already talent-laden recruiting class.  It's great to  keep a wrestler like Barker in-state, and we're very fortunate to get him  back."    Coached by former MU standout Rocky Streb at Oakville High School in St.  Louis, Mo., Barker turned heads with a 161-16 record in his high school  career. As a four-time state qualifier, Barker placed second at the state meet his sophomore year, and won the tournament in both his junior and  senior seasons.    Barker competed at the national level as well, placing third in the freestyle junior national tournament in Fargo, ND and winning the high  school national tournament in Pittsburgh, Pa.    Internationally, Barker traveled to Russia on a wrestling exchange with  fellow MU signee Tyron Woodley.  Former MU two-time All-American Khris  Whelan coached the exchange team.