Melvin Peterson, whose greatest riding success came at Santa Anita, died Jan. 3 in Phoenix, Arizona. He was 83.Raised on a farm in Utah, Peterson won the 1947 Santa Anita Handicap on South American import Olhaverry and missed winning the 1945 running aboard Texas Sandman by a head. Peterson also rode in two Kentucky Derbys. He finished fourth on Billings in Citation's 1948 Derby score and was unplaced on Ky. Colonel in the Derby the following year.Peterson trained after hanging up his tack.