Construction has begun on the first phase of Quince Tree Executive Office Center at the intersection of West Diamond Avenue and I-270 in Gaithersburg, the developer, Potomac Investment Associates, has announced.

Two office buildings, with 67,000 square feet of space, will be built in the initial stage.

The 14-acre facility was designed by Lewis/Wisnewski Associates of Alexandria. Tiber Construction Co. is in charge of construction.

Weaver Brothers Inc. has been selected as agent for the buildings.

Other recent developments in commercial realty in the Washington metropolitan area:

* Jerry's Systems Inc., franchisor of Jerry's Sub Shop, has signed a lease with Lerner Corp. for retail space on the lower level of White Flint Mall.

* CMC Inc., a security consulting firm, has leased 7,000 square feet for $1.5 million at 1655 North Fort Myer Dr. in Arlington from the building's owner, Lewis, Wilson, Lewis & Jones.

* Sperry Corp., a government contracting firm, has signed a sub-lease for 20,000 square feet at 8229 Boone Blvd. in Vienna with GTE Telenet, the building's primary tenant.

* Congoleum Corp. has leased 2,500 square feet at Capitol Place in Washington. The $340,000, multi-year lease was signed with Blum Frank & Kamins, owner of the building.

* Kenneth H. Wells & Associates Inc., an insurance firm, has signed a $45,000 lease for 1,300 square feet at 3933 University Dr. in Fairfax.

* Fokker Aircraft USA Inc., the American subsidiary of the Dutch airplane manufacturer, has leased an additional 4,500 square feet at Trans Potomac Plaza in Alexandria. The $400,000 lease was signed with Bryce Mountain Inc., the facility's owner. In addition, the National District Attorneys Association has leased 8,000 square feet at Trans Potomac Plaza for $800,000.

* Cort Furniture Rental Corp. has signed a $1 million lease with Tysons Tower Limited Parntership for 4,000 square feet of retail space at 8500 Leesburg Pike in McLean.

* Peregrine White Co. has leased 1,500 square feet at 1400 K St. NW for $125,000. The owner of the building is JBG Associates.

* Bell Atlanticom Corp., a division of Bell Atlantic Corp., has leased 50,000 square feet at the ORI building at 1400 Spring St. in Silver Spring.