Singing Susan, the overwhelming favorite for the $35,000-added Free State Stakes for 3-year-old fillies at Bowie yesterday, shattered her right front knee approaching the stretch turn and had to be destroyed there by the track veterinarian.

Singing Susan, winner of six of eight starts, was being raced for the first time in 1983. The daughter of Rollicking had been bought by Theodore Sabarese of Verona, N.J., from Robert Quinichett of Washington, reportedly for $900,000, after she won her first five races last year.

"I can't understand it," said trainer John Parisella. "She made the lead without any trouble and was moving well."

Singing Susan broke well in the six-furlong feature and held a slight lead until the far turn, where jockey Alfredo Smith asked for more speed.

She responded with a short burst before staggering. Smith pulled her up, then veterinarian Patricia Brackett examined the horse before deciding she should be destroyed.

"Singing Susan had a multiple fracture of the knee," Brackett said. "There was no chance of saving her."

Holiday Dancer, second choice of the crowd of 13,132, had to avoid the injured favorite before making her move deep in the stretch to beat Northern Athena. Holiday Dancer, ridden by Donald Miller, paid $8.20 after winning in 1:11 4/5.

Last Saturday, What A Michael had to be destroyed after breaking down approaching the stretch turn in the Stryker Handicap.