PERNELL ROBERTS , 81

Actor on 'Bonanza,' 'Trapper John'

Pernell Roberts, a versatile actor best remembered for his portrayal of the handsome, eldest Cartwright son on the classic television Western "Bonanza" and later as the lead character in the medical drama "Trapper John, M.D.," died Sunday of cancer at his Malibu, Calif., home.

Mr. Roberts became a star as Adam Cartwright, the heir apparent of the fictional Ponderosa ranch, a role he filled from the show's debut in 1959 until 1965, when he left the cast despite the series' immense popularity. "Bonanza" remained on the air for eight more years without him.

Mr. Roberts was the well-educated and mature brother, who played Adam with a suave manner that won a legion of fans. He found the role unfulfilling, however, and left the show at its peak, a decision that caused him to be "scratched off by most of his contemporary fellow actors as some kind of a nut," Los Angeles Times critic Hal Humphrey wrote in 1967.

His comeback role was Dr. John McIntyre in the CBS drama "Trapper John, M.D." based on the character from the popular comedy "M*A*S*H." His work on "Trapper John" earned him an Emmy nomination for best dramatic actor in 1981.

After the show ended in 1986, he made guest appearances on other series and TV movies, narrated a documentary and hosted the short-lived "FBI: The Untold Stories" (1991). He retired in the late 1990s.