  We consider the N=1 super Yang-Mills theory with gauge group U(Nc) or SU(Nc)
and one adjoint Higgs field with an arbitrary polynomial superpotential. We
provide a purely field theoretic derivation of the exact effective
superpotential W(S) for the glueball superfield S in the confining vacua. We
show that the result matches with the Dijkgraaf-Vafa matrix model proposal. The
proof brings to light a deep relationship between non-renormalization theorems
first discussed by Intriligator, Leigh and Seiberg, and the fact that W(S) is
given by a sum over planar diagrams.
