© 2020, The Author(s).We explore t-b-? Yukawa unification (YU) in a supersymmetric SU(4)c× SU(2)L× SU(2)R model without imposing a discrete left-right (L-R) symmetry. A number of interesting solutions that are compatible with t-b-? YU, LSP neutralino dark matter (DM), and LHC and other experimental constraints are identified. In particular, they include gluino-neutralino and stau-neutralino coannihilation scenarios, where the NLSP gluino mass can range from 1–3 TeV. Higgsino-like dark matter solutions are also identified for which gluino masses can approach 5 TeV or so. This scenario will be tested at LHC Run-3 and its future upgrades.