The real winner of an intense competition among harness tracks in the Delaware Valley will emerge today in Maryland, when Gov. Harry Hughes is expected to sign a bill seen as the salvation of harness racing in the state.

With Delaware Valley tracks adding enough days to their meets to threaten a horse shortage in Maryland, the state legislature acted quickly to protect its harness racing industry, which has expanded considerably in recent years in quality, racing days and breeding. It employs 4,000 people.

The bill that passed the Maryland House and Senate with only nine dissenting votes will add 90 racing days annually, meaning there now will be year-around harness racing in the Washington area. More significantly, it will reduce the state tax from 6 percent to three-quarters of 1 percent by July 1, 1984. In the interim, it goes to 3 1/2 percent July 1. This brings the tax structure in line with surrounding states. The thoroughbred tax remains at 4.09 percent.

"In terms of business, it means survival," said William E. Miller II, president of Rosecroft and grandson of the track's founder.

Rosecroft, sitting on 100 acres of prime land in Oxon Hill near a planned Metro subway station, lost almost $625,000 in 1981 and 1982; Freestate lost $2 million in the three years since Washington lawyer Frank DeFrancis took over a scandal-ridden, decrepit plant and started improving it.

"This year was a watershed year," said Miller. "I told this to the stockholders. We were in a very precarious position. We had to borrow $600,000 to get us through the fall and winter, our equity was almost nil (about $225,000) and I'm not sure there was a bank that would lend us another $600,000."

In a rare show of cooperation between track owners, horsemen and breeders, DeFrancis, a horseman and former general counsel for the governments of Italy and West Germany, went to Annapolis and told the legislature how an escalation of racing dates in the Delaware Valley would cause a horse shortage in Maryland and decline for the local industry.

DeFrancis emphasized his industry's impending death by taxation. He described how within two years the Delaware Valley circuit would have 200 more nights of racing and thus the need for 20,000 more horse starts; many of those likely would come from the 1,000 horses competing on the Maryland circuit.

Here's how the war developed:

In August, Brandywine (near Wilmington, Del.) announced it would request to open in March and would seek an increase from 85 to 140 nights of racing, thus going head to head against Liberty Bell in the spring. In December, Liberty Bell, near Philadelphia, countered by announcing it would increase from 205 to 250 racing nights a year.

Finally, in New Jersey, the governor signed a bill making the state tax for new track owners one-half of 1 percent. Interest was renewed in reopening Garden State Park near Philadelphia, and it is expected to have 100 nights of harness racing as early as 1985. Its owner is Robert Brennan, who made his fame with First Jersey Securities.

Thus, Maryland had a harness racing crisis. To the north were the Meadowlands, Yonkers and Roosevelt, the biggest harness tracks with the biggest purses in the East; to the south was Maryland and its 6 percent state tax, making it a prime source of horses for the Delaware Valley tracks.

"Maryland was operating under the most archaic structure," DeFrancis said. "We couldn't defend ourselves against this kind of competition for the harness horse. You could take a horse racing here for a $4,000 purse and race him for 50 percent more in Delaware against the same competition. So, there was a fundamental statewide decision to be made: is it going to be competitive?"

Even before that decision was made in Annapolis, both tracks in the Washington area were aggressively marketing their product, Rosecroft even using a precedent-setting direct-mail campaign.

At Rosecroft, last year's average handle for a split meet was $404,000; going into this week, the average was $529,796, a pace that will break Freestate's record average state harness handle of $491,000 last year when its percentage of increase was second highest in the nation.

The average Rosecroft attendance is up from 4,081 to 4,677 in a year. A key move by Rosecroft has been five-day race weeks with Mondays and Tuesdays dark; the track started racing on Tuesday earlier this month, but will revert to five-day weeks for the fall and winter meetings.

Even without the new legislation, General Manager Tom Aldrich expects Rosecroft to show about a $50,000 profit this meet and about $300,000 for the year with the addition of 60 days this fall and a 3 1/2-percent state tax.

The lower taxes are expected to double purse money by July 1, 1984.

The Harness Board of the Maryland Racing Commission has to approve the additional dates, but the plans now are for Rosecroft to reopen Sept. 21 and race through Dec. 11. It will reopen for 1984 in January and race through May 15, when Freestate will start its entire 115-day meeting, racing six nights a week.

Under this setup, Rosecroft races 145 days, including 30 of Ocean Downs' dates, but Freestate has the summer dates and avoids head-to-head competition against nearby Laurel Race Course.

"Harness racing is ready to explode," said DeFrancis. CAPTION: Picture, Maryland bill would help such tracks as Rosecroft, which had lost almost $625,000 in 1981 and 1982. By Richard Darcey -- The Washington Post