ASPECTS OF T-DUALITY IN OPEN STRINGS

We study T-duality for open strings in various D-manifolds in the appr oach of canonical transformations, We show that this approach is parti cularly useful to study the mapping of the boundary conditions since i t provides an explicit relation between initial and dual variables. We consider non-abelian duality transformations acid show that under som e restrictions the dual is a curved (d - dim G - 1) D-brane, where d i s the dimension of the space-time and G the non-abelian symmetry group , The generalization to N = 1 supersymmetric sigma models with abelian and non-abelian isometries is also considered.