Mary Kay Johnson, wife of Hall-of-Fame trainer Phil “P.G.” Johnson, died Tuesday night at St. Francis Hospital in Roslyn, N.Y., of an apparent heart attack. She was 79.

The Johnsons were married for 59 years. Along with their daughters, Kathy and Karen, they raced horses under the nom-de-course Amherst Stable, whose top runner, Volponi, won the 2002 Breeders’ Cup Classic.

The family requests that memorial gifts be made to the Ronald McDonald House, 267-07 76th Ave., New Hyde Park, N.Y., 11042; (516) 775-5683.