A one-piece truss adapter for supporting single-axis trackers with truss foundations. A upside-down Y-shaped structure has bearing support portion and an opposing pair of legs with an angularly adjustable connector for securely joining the one-piece adapter to a pair of driven screw anchors at different angular orientations. Each leg terminates in a connector that is received in a socket integral to a driving coupler at the head of each screw anchor. A retaining nut may hold the connector in place to complete the angularly adjustable assembly.