Major thoroughbred racing returns to Maryland today as Bowie opens its 36-day meeting. Post time will be 1 p.m. and today's feature will match undefeated Valerie's Best against eight 2-year-old female rivals in the $45,350 Marlboro Nursery at seven furlongs.

Valerie's Best has won her two career starts by a combined total of 18 lengths in New Jersey. She will again be ridden by James Terry. Chief contention is expected to come from the highweights Ting A Ling and Rob's Lady, both carrying 116 pounds, three more than Valerie's Best.

Timonium Race Course closed its 42-day meeting yesterday with a 1 percent rise in betting and a 1.3 percent rise in attendance. General Manager Max Mosner said, "We did well with our two Sunday racing dates, but not as well as we'd hoped for. We'll almost surely ask the Maryland legislature for two more Sundays next year."

Phil Grove, Timonium's leading rider for the past three years, had 57 victories from 248 mounts. His nearest competitor was apprentice Albert Delgado with 52.

King T. Leatherbury, supended for the first time in his 27-year career when one of his mounts was found with an excess of Butazolidin, was again the leading trainer with 17 winners in 67 entries.

Jockey Gunnar Lindberg injured his right shoulder and heel yesterday when his mount, Tiny Nun, fell in the run for the first turn in the seventh race at Timonium. Lindberg, who had ridden 17 winners at the meeting, was taken to Greater Baltimore Medical Center for treatment.

The seventh race, the $15,000-added Debby's Turn Stakes for 2-year-old fillies, was won by longshot Owner Pressure, but that horse was disqualified for fouling Tiny Nun and placed out of the money. No Body Else's, the second-place finisher, was moved up to the win slot and Escape Artist, ridden by Delgado, who rode five winners on the 10-race card, was moved up to second.