Roles of Z₂-odd N=1 multiplets in off-shell dimensional reduction of 5D supergravity

We discuss the dimensional reduction of five-dimensional supergravity compactified on S^1/Z_2 keeping the N=1 off-shell structure. Especially we clarify the roles of the Z_2-odd N=1 multiplets in such an off-shell dimensional reduction. Their equations of motion provide constraints on the Z_2-even multiplets and extract the zero modes from the latter. The procedure can be applied to wide range of models and performed in a background-independent way. We demonstrate it in some specific models.