The models of normal open induction are those discretely ordered rings
, integrally closed in their fraction field whose nonnegative part sat
isfy Peano's induction axioms for open formulas in the language of ord
ered semirings. It is known that neither open induction nor the usuall
y studied stronger fragments of arithmetic (where induction for quanti
fied formulas is allowed), have the joint embedding property. We prove
that normal models of open induction have the joint embedding propert
y.