The sound of powder-pounding thoroughbreds at Marlboro Race Track once was confined to memory. Now, twice a year, the track comes alive under the guise of Prince George's Equestrian Center and the first of those programs begins today at noon.

This is the third straight year of reawakening for Marlboro, which closed in 1972 after 58 years of racing. Tents and bleachers help bring a country-fair ambiance to the little Upper Marlboro track on Pennsylvania Avenue, although some polish is added; once again, prominent racing announcer Dave Johnson will call the action.

The 10-race card is geared to the unexceptional, with eight races offering $3,000 purses. Also, there are two 3 1/2-furlong races, the shortest run in Maryland. The $15,000 Marlboro Nursery for 2-year-olds marks the day's richest gathering, but the most interesting seems a $6,000 starter allowance race featuring two of the country's biggest race-winners this year, Jilsie's Gigalo and Bolting Holme.

Jilsie's Gigalo leads with 11 victories in 16 tries; Bolting Holme (10 for 17) shares second with a horse named Why Madie Why. The attractive matchup was put together by racing secretary Georganne Hale, but there was some uncertainty as to whether it will materialize. Trainer Jim Woods attempted to withdraw Bolting Holme yesterday, but with only four others entered, the stewards refused, making the horse "stuck." Woods could not be reached for comment.

General admission is $3, entrance to the Marlboro Club (a large, heated tent) $8, parking $1 and $2. Exactas will be offered on each race, triples on five races and a daily double on the first two. Gates open at 10:30 a.m. Whistling Dixie

Churchill Downs, Pimlico and Belmont Park have formed the "Triple Turf Challenge," a series of three turf races that will pay $1 million to a horse who can win all three beginning in 1991.

The series, guaranteed for three years and sponsored by Early Times distillers, will encompass the Turf Classic from Churchill Downs on May 3, the Dixie Handicap from Pimlico on May 17 and the Manhattan Handicap from Belmont Park on June 7. ESPN will televise each race. . . .

Laurel's sloppy track condition prompted a spate of withdrawals from yesterday's program. The $23,000 allowance feature was reduced from seven to three starters -- which eliminated place and show wagering -- after the race was taken off a saturated turf course.

Although only $57,154 was wagered on the race, Laurel and off-track Pimlico managed to handle $1,038,586 for the day. According to the mutuels office, Laurel hasn't handled less than $1 million for a 10-race card since Nov. 6, 1989.

El Santiaguero led gate-to-wire, a recurring theme at Laurel yesterday. The eight-length victory was his first since New Year's Eve. . . .

Trainer Carlos Garcia, refuting a published report, said Valay Maid will run in Saturday's $1 million Breeders' Cup Distaff at Belmont Park. The filly worked five slop-filled furlongs in a minute flat yesterday at Laurel.

Garcia knows Valay Maid will be testing the greats of her division -- Go For Wand, Bayakoa, Gorgeous -- but said, "How many chances do you have to run for that kind of money? If she wasn't doing good, I wouldn't even bother."

The 3-year-old filly won the Cotillion Stakes at Philadelphia Park by five lengths in her last start. She has won six of 12 races and $378,180 this year, but has not faced older horses or a cast as strong as that of the Distaff. Garcia said she will leave for New York Thursday and gallop over the track Friday morning. . . .

Trainer King Leatherbury, sanctioned following a recent medication violation, was granted a stay of suspension pending a hearing before the Maryland Racing Commission.