The Tysons West Metro station on Route 7. (Jeffrey MacMillan/Capital Business)

Ownership of the most prominent development project in Tysons Corner splintered recently after a deal between two of its principals — the Cherner family of auto dealers and developer Aaron Georgelas — fell through.

The Cherners agreed to a contract with Georgelas in 2006 that would allow the family’s auto dealerships to be included in the Tysons developer’s plans for a 6 million-square-foot high-rise development at the corner of Leesburg Pike and Spring Hill Road. The two since worked side-by-side to argue for county development rules that would permit an urban Tysons Corner and to integrate their properties.

But the Cherners and Georgelas failed to extend their contact in recent weeks, raising the possibility that the development, which Fairfax County selected as its demonstration project for new Tysons zoning rules, could be developed piecemeal.

The Georgelas and Cherner families have both run businesses in Tysons Corner since the 1960s. Including the five Cherner dealership properties, Georgelas had amassed 28 acres around the coming Tysons West Metrorail station and planned a total of 18 buildings. He was first to receive approvals under Tysons new zoning rules and inked a deal with Greystar to purchase land for a 25-story, 400-unit apartment tower now under construction.

But the Cherner properties are closest to the Metro station, set to open in late 2013. Without them Georgelas is left with a U-shaped footprint that circles a seven-acre, Cherner-owned core.

Jonathan Cherner, who runs Cherner Automotive Group with his brother Andrew, said the contract offered an opportunity to purchase the dealership land. “They had an option to buy the property, and they allowed that option to expire,” he said. “It’s as simple as that.”

“I think the world fundamentally changed several years ago [with the economic collapse], and I think it fundamentally changed for many industries, and the development industry was certainly one of them,” he said.

Cherner is considering partnering with another developer or buyer, or moving through zoning independently. He said his priority was getting the Cherner and Georgelas properties zoned cohesively. “I think it’s just important that they all move through in a cohesive manner so that a common vision is achieved. We continue to be really bullish on the demonstration project and the vision that the county and Aaron have helped design,” he said.

Aaron Georgelas said he hoped the deal could be revived but declined to elaborate. Cherner said he would not rule out working with Georgelas in the future. “We know and they know that we’re still very much linked at the hips because of our properties,” he said.

The county will continue to focus on the project despite its fractured ownership, said Barbara Byron, director of the county’s Office of Community Revitalization and Reinvestment. “Ideally, we do want the consolidations and I think that helps in terms of the development of Tysons,” she said. “But we also understand that there are also difficulties with effectuating them, and while it’s unfortunate we understand it and we’re trying to work both the Georgelas and the Cherner piece, while independently, within an overall concept.”