LEXINGTON, Ky. - Summer Squall, the 1990 Preakness winner who sired the 1999 Horse of the Year, Charismatic, was euthanized Tuesday because of the infirmities of old age, according to Lane's End Farm.\nSummer Squall, who stood at the Versailles, Ky., farm throughout his career until a fertility decline prompted the farm to pension him in 2004, was 22.\nLane's End owner William S. Farish III and partner W.S. Kilroy bred Summer Squall by mating Storm Bird to its 1992 Broodmare of the Year, Weekend Surprise, by Secretariat. She later also produced the 1992 Horse of the Year, A.P. Indy, winner of the Belmont Stakes and Breeders' Cup Classic and now Lane's End's flagship sire.\nSummer Squall raced for Dogwood Stable, a public syndicate whose principal, Cot Campbell, bid $300,000 for the colt at the 1988 Keeneland July select yearling sale. Trained by Neil Howard, he won 13 times, earning Grade 1 victories in the Preakness and Hopeful stakes. He bankrolled $1,844,282.\nUndefeated in five starts as a juvenile, the bay colt entered into a rivalry with eventual champion Unbridled at 3. Summer Squall beat Unbridled in the 1990 Blue Grass Stakes, but Unbridled turned the tables in the Derby, beating second-placed Summer Squall by 3 1/2 lengths. Summer Squall bounced back to defeat Unbridled in the Preakness. Both lost in the Pimlico Special. In the 1991 Fayette Handicap, Summer Squall soundly beat Unbridled en route to the Breeders' Cup Classic at Churchill, where they both finished behind winner Black Tie Affair.\nIn addition to Charismatic, who was 1999's Derby and Preakness winner and champion 3-year-old in addition to Horse of the Year, Summer Squall sired Storm Song, the 1996 champion juvenile filly and winner of that year's Breeders' Cup Juvenile Fillies. He also is the sire of Grade 1-winning millionaire Summer Colony among his 35 black-type winners.