  It is shown that the combined constraints on the amount of cold dark matter
and of proton stability produce a stringent upper limit on the gluino mass
$m_{\tilde g}$ (and hence on the lightest neutralino mass $m_{\chi_1^0}\simeq
m_{\tilde g}/7$) for a large class of gravity mediated supergravity unified
models. One finds that for the minimal SU(5) model current data (Kamiokande)
restricts $m_{\tilde g}\leq 400$ GeV for a scalar soft breaking mass $m_0\leq
1$ TeV. Expected future data from Super Kamionkande and ICARUS will be
sensitive to the entire range of gluino mass for $m_0\leq 1$ TeV, and be able
to exclude the region $m_{\tilde g}\geq 500$ GeV for $m_0\leq 5$ TeV. Effects
of quark mass textures are studied and one finds that the bound $m_{\tilde
g}\leq 500$ GeV holds when the experimental proton lifetime for the $p\to \bar
\nu K^+$ mode becomes $\geq 5\times 10^{32}$ yr.Implications of these results
for a test of these models at the Tevatron and at the LHC are discussed. The
effects of non-universal soft breaking in the Higgs and the third generation
squark sectors are also examined, and it is found that the proton lifetime is
sensitive to these non-universal effects. The current data already eliminates
some regions of non-universalities. The constraints of proton stability on the
direct detection of dark matter are seen to reduce the maximum event rates by
as much as a factor of $10^3$.
