Classic winner and prominent sire Summer Squall has been retired from stud duty at William S. Farish's Lane's End Farm near Versailles, Ky., due to continuing problems with his fertility. The 17-year-old son of Storm Bird covered only 10 mares last breeding season.Summer Squall, unbeaten as a 2-year-old and winner of the 1990 Preakness Stakes (gr. I), entered stud at Lane's End in 1992 and is represented by 31 stakes winners, His son Charismatic was 1999 Horse of the Year after winning the Kentucky Derby (gr. I) and Preakness. A daughter, Storm Song, was named champion 2-year-old filly of 1996 following her score in the Breeders' Cup Juvenile Fillies (gr. I). Summer Squall, who is the sire of additional grade I winner Summer Colony, has sired the earners of $27 million.Summer Squall was bred by Farish in partnership with W.S. Kilroy and purchased by Cot Campbell's Dogwood Stable for $300,000 out of the 1988 Keeneland July yearling sale. His big score his 2-year-old season came in the 1989 Hopeful Stakes (gr. I) at Saratoga. He ran second to Unbridled in the Kentucky Derby, then beat that rival in the Preakness.Summer Squall raced as a 4-year-old and was retired with 13 wins from 20 starts and $1,844,282 in earnings. His half-brother, A.P. Indy, was 1992 Horse of the Year and entered stud at Lane's End the following year. A.P. Indy led the 2003 general sires list and ranks atop this year's list. Their dam, Weekend Surprise (by Secretariat), is a Kentucky Broodmare of the Year.