Heat oven to 375°F. Brush whole chicken and squash pieces with butter; sprinkle with salt, garlic powder, ginger and pepper. Place chicken in shallow roasting pan; set squash aside. Insert ovenproof meat thermometer into chicken so tip is in thickest part of inside thigh and does not touch bone.
Roast chicken uncovered 30 minutes. Meanwhile, in small bowl, mix teriyaki baste and glaze with juice concentrate.
Remove chicken from oven. Arrange squash around chicken; brush teriyaki mixture over chicken and squash.
Return to oven; roast uncovered 20 minutes. Brush remaining teriyaki mixture over chicken and squash; cover chicken loosely with foil. Roast 25 to 40 minutes longer or until squash is tender, and thermometer in chicken reads 180°F and legs move easily when lifted or twisted. Garnish with orange wedges, if desired.