  We study non perturbative superpotentials for N=1 super Yang Mills from the
point of view of large $N$ dualities. Starting with open topological strings we
work out the relation between the closed string sector dilaton tadpole, which
appears in the annulus amplitude, and NSNS fluxes in the closed string dual on
the resolved conifold. For the mirror closed string dual version on the
deformed conifold we derive, for a non vanishing $G_{3}$ form, the $N$
supersymmetric vacua and the transformations of $G_{3}$ through domain walls.
Finally, as an extension of Fischler Susskind mechanism we find a direct
relation between the dilaton tadpole and the geometric warping factors induced
by the gravitational backreaction of NSNS fluxes.
