Without strong challenges to top incumbent officeholders in Maryland, the 1990 election was supposed to be a formal exercise with little bearing on the coming four years.

It hasn't turned out that way, though. State House leaders now expect the Nov. 6 general election to deliver strong signals from Maryland's 2.1 million registered voters about tax increases, growth and development, the involvement of special interests in politics and whether Republicans have moved the state closer to two-party status.

After the Sept. 11 primary ouster of four incumbent state senators, the November election for members of the General Assembly also will go a long way toward determining what restrictions, if any, the state will place on women's access to legal abortions.

Democratic Gov. William Donald Schaefer, who served 15 years as Baltimore's mayor, is conducting what most observers believe will be his last political campaign in a state that limits governors to two terms.

After a nonchalant primary campaign, Schaefer, 68, has returned to classic stumping this fall. He holds a more than 20 to 1 fund-raising edge and a wide lead in the latest independent polls. Yet, he appears unlikely to defeat Republican William S. Shepard of Potomac, with the 82 percent of the vote he captured in 1986.

Shepard, 55, generated widespread criticism when he chose his wife to be his lieutenant governor running mate, and his campaign never recovered sufficiently to draw significant contributions and support.

In three of the state's most populous counties -- Montgomery, Anne Arundel and Baltimore -- dissatisfaction with rising property taxes took on the earmarks of revolt. If voters favor ballot questions that limit annual tax increases, as polls suggest, the message also will be felt in Annapolis. Early next year, lawmakers are expected to consider proposals to increase state income, sales and gasoline taxes.

The anti-growth tide that led to Montgomery County Executive Sidney Kramer's narrow Democratic primary defeat will be tested again Nov. 6. In an unusual move, Kramer is mounting a write-in campaign to defeat veteran County Council member Neal Potter in the executive's race. In Baltimore County, incumbent County Executive Dennis Rasmussen, a Democrat, faces a surprisingly strong challenge based largely on resentment against taxes and growth.

Though Democrats still hold a 2 to 1 edge in Maryland voter registration, Republicans viewed 1990 as a chance to cut into the Democrats' dominance in fast-growing suburban counties and in the 1st Congressional District.

After falling only 1,500 votes short of defeating Democratic Rep. Roy P. Dyson two years ago, Wayne Gilchrest prevailed in an eight-man Republican primary field in the 1st District and was tapped by the national party organization to get strong GOP attention heading into the November race.

Dyson has represented the district, which covers southern Maryland, the Eastern Shore and part of Harford County, for five terms. But he has been constantly on the defensive because of his close financial ties to special interests and has been questioned about how his hawkish conservatism squares with his recently discovered designation as a conscientious objector during the Vietnam War.

The other incumbent members of Congress from Maryland are favored to win reelection.

In Anne Arundel County, Republicans hope to pick up the county executive's office. Former House of Delegates minority leader Robert R. Neall was considered the early front-runner against Democrat Theodore Sophocleus, but recent polls showed the race too close to call.

Republicans also hope to gain ground in the 188-member General Assembly, where the GOP held only 24 seats for the last four years. Some of their best opportunities, Republicans said, were in Howard, Montgomery, Baltimore and Carroll counties.

Among Democratic statewide officeholders, Comptroller Louis L. Goldstein faces Republican Larry M. Epstein, and Democratic Attorney General J. Joseph Curran Jr. is matched against Republican Edward L. Blanton Jr.

Abortion-rights advocates claim that the September primary assured them majority support in the state Senate and House, but they concede that the outcome of a handful for general election contests will determine what kind of concessions they must make to get a bill passed in the General Assembly next year.

In Prince George's County there are races for Congress, county executive, state's attorney, County Council, school board, state legislature and several courthouse posts.

With the exception of the state's attorney contest, all of the Republican candidates are viewed as long shots in this heavily Democratic county. That race pits incumbent Democrat Alex Williams against Arthur A. Bud Marshall, the man he defeated in the Democratic primary four years ago. Marshall, who held the state's attorney post for 24 years before losing the 1986 primary, has switched to the Republican Party. Neither man faced primary opposition.

In the County Council races, two Democrats face no opposition -- Hilda Pemberton, the incumbent, in the 7th District and James C. Fletcher Jr. in the 5th District. The 5th District incumbent, Floyd E. Wilson Jr., lost in the Democratic primary for county executive. The incumbent Democrat in the 2nd District, Anthony J. Cicoria, is on trial on charges of filing false tax returns and theft. A conviction would not necessarily preclude Cicoria from beginning a third term in January if he is reelected in November.

Democrats are running unopposed in three of the county's eight state Senate districts. They are Decatur W. Trotter, Albert R. Wynn and Gloria G. Lawlah, a member of the House of Delegates who defeated incumbent Frank Komenda in the Democratic primary. The Republican Party, which earlier this year was advertising for candidates to run in Prince George's County, was unable to field full slates in the House of Delegates races in the same districts.

Three of the school board's nine seats are on the ballot this election. Suzanne M. Plogman is running unopposed in the 2nd District. In the 5th District, Kenneth E. Johnson faces Verna Teasdale. The 8th District race pits James M. Davis against Frederick Hutchinson. Both races are nonpartisan.

Also on the ballot in Prince George's are contests for Circuit Court judge, Orphans' Court judge, Circuit Court clerk, register of wills and sheriff.