Chester H. Ferguson, chairman of the board of the billion-dollar Lykes Brothers conglomerate and former chairman of the Florida Board of Regents, died in March 1983 He was 74 years old and had been in a coma since apparently suffering a heart attack on Feb. 8 1983. Mr. Ferguson was a principal partner in the Tampa law firm of Macfarlane, Ferguson, Allison & Kelly. He was also chief executive officer of First Florida Banks. In 1965 he was appointed to the first Board of Regents, the agency that supervises Florida's university system, and he became chairman in the late 1960's. Mr. Ferguson, who held a law degree from the University of Florida, moved to Tampa in 1930 and acted as the city's first unpaid public defender. Later that year he joined the law firm and five years later he became a full partner. In 1939 Mr. Ferguson married Louise Lykes, daughter of Howell T. Lykes, a banker who was one of the founders of the Lykes Brothers cattle and shipping empire. In the late 1960's he was named chairman of the board of Lykes Brothers, which by then had expanded to banking, citrus and meatpacking. Survivors besides his wife include a daughter, Stella Louise Thayer of Tampa, and a son, Howell, of Tallahassee.