Exposure to –20 °C did not reduce seed
germinability, and the seeds maintained their
ability to germinate with or without GA3.
Germination after –20 °C treatment appeared
to be influenced by seed m.c. Seeds
dehydrated for 3 d (5.3% m.c.) germinated
better irrespective of the germination medium
(water or GA3). The positive effect of
exposure to –20 °C strengthens the conclusion
that papaya seed shows an orthodox
behavior. However, this result is in disagreement
with the related observation that papaya
germinability was affected negatively by
storage at –20 °C (Ellis et al., 1991). These
contrasting findings may explain the variation in the degree of dormancy and the
requirements for breaking it exhibited by
different seed populations of papaya (Baskin
and Baskin, 1998).