Assuming the Lusztig conjecture on the irreducible characters for reductive algebraic groups in positive characteristic p, which is now a theorem for large p, we show that the modules for their Frobenius kernels induced from the simple modules of p-regular highest weights for their parabolic subgroups are rigid and determine their Loewy series.Let G be a reductive algebraic group over an algebraically closed field k of positive characteristic p, P a parabolic subgroup of G, T a maximal torus of P , and G 1 (resp. P 1 ) the Frobenius kernel of G (resp. P ). In this paper we study the structure of G 1 Tmodules induced from the simple P 1 T -modules of p-regular highest weights. Thus our study goes parallel to parabolically induced Verma modules in characteristic 0. In case P is a Borel subgroup of G, assuming Lusztig's conjecture for the irreducible characters for G 1 T , which is now a theorem for large p thanks to [AJS] . We now show that the parabolically induced modules are also rigid and describe their Loewy series.To go into more details, let B be a Borel subgroup of P containing T , Λ the character group of B, R ⊂ Λ the root system of G relative to T , and R + the positive system of R such that the roots of B are −R + . We let R s denote the set of simple roots, and I a subset of R s such that the root subgroups U α of G associated to α ∈ I generate P together with B. Denote by∇ P the induction functor from the category of P 1 T -modules to the category of G 1 T -modules, and letL P (λ) denote the simple P 1 T -module of highest weight λ ∈ Λ. Our object of study is∇ P (L P (λ)). After stating some generalities in § §1 and 2, we specialize into the case where λ is p-regular, i.e., if α ∨ is the coroot of each root α and if ρ =