The Washington Board of Realtors and the Mortgage Bankers Association of Metropolitan Washington will begin their annual joint convention Wednesday at the Homestead in southern Virginia. Sessions will be held Thursday through Saturday.

Tyson Developers Inc. recently purchased 10.7 acres at the northwest corner of Rte. 123 and Old Courthouse Road in Tysons Corner for $6 million. The purchaser plans a large office complex on the former site of the first Fairfax County courthouse. Barnes, Morris & Pardoe Inc. handled the transaction.

Edward Murphy has been named relocation director of Realty-World Springfield and Beverly Meredith has been named property manager of the same firm.

Fred J. Gibson of Cedar Rapids, Iowa, has been elected president and chief executive officer of Partners Real Estate Inc., a franchise group formerly headed by Washingtonian James S. Bugg, who now is chairman of the board. Gibson said that corporate headquarters will be moved to Cdar Rapids in July. Partners currently has offices both in Washington and Cedar Rapids.

Martin K. Alloy, president of Stanley Martin Communities Inc. a home building firm in Silver Spring, is one of the four newly elected directors of the Home Owners Warranty Corp., which administers a nationwide warranty and insurance program on new houses.

Robert V. McGrath, president of the Northern Virginia Board of Realtors, has joined RE-MAX Distinctive Properties in McLean as vice president. McGrath formerly owned his own firm but sold it earlier this year to Peck Properties.

The Suburban Maryland Home Builders Association will hold its annual gold and tennis outing Monday at the Germantown Country Club.

Dorothy Elmendorf, formerly director of advertising for Mount Vernon Realty, has joined J. Edwards Real Estate Co. as sales manager of the Mount Vernon office.The Edwards firm plans to open an office in Old Town Alexandria later this year.

Tysons Realty, headed by Pauline Thompson, recently handled the sale of two small apartment buildings in Rosslyn. A 14-unit building was sold for $350,000 to Rhodes Street Association and a 15-unit building was sold for $315,000 to Pierce Street Associates.

Sales are under way at George Mason Village, a garden-style condominium apartment complex with 163 units at S. Goerge Mason Dr., Arlington. Prices begin at $42,000.

Crestwood Village, an adult community just southwest of Frederick, Md., recently marked its first anniversary with the dedication of a $1.5 million clubhouse.

Sandy Petersen of Long & Foster Realtors recently became the first woman in Virginia to earn the certified commercial investment member designation from the National Association of Realtors.

The Property Management Association of Washington plans an exposition Oct. 16 at the Capital Centre in Landover.

Robert Baker of Century 21/Kadow Inc. in Bethesda has earned a graduate Realtor designation by completing educational courses prescribed by the National Association of Realtors.

Crofton Village, a 258-unit rental garden apartment development, has been opened at 911 Nantucket Rd., Crofton. Two- and three-bedroom apartments are being rented by Dreyfuss Brothers.

Sales are under way to residents in the first section of the 979-unit Belle View garden apartment complex in S. Alexandria, where International Developers Inc. is the developer of the condominium conversion. The sales office is in the 1100 block of Belle View Boulevard.