  The correlations between planetary nebula (PN) morphology and the nature of
their progenitors are explored by examining homogeneous PN samples in the
Galaxy and the Magellanic Clouds. We selected PNe with reliable abundances from
spectral analysis, and whose morphology is known, and compared the abundances
of the element at variance with stellar evolution with the final yields of
Asymptotic Giant Branch (AGB) stellar models. We found that most asymmetric PNe
derive from the evolution of massive AGB stars both in the Galactic disk and
the Magellanic Clouds.
