In order to determine how well PDR would perform
under the conditions in commercial plantings with continuous
exposure to PRSV inoculum, an experiment
was installed in a drip-irrigated field at the University
of HawaiiWaimanalo Experiment Station at 15melevation
on the windward (northeast) coast of Oahu. The
experiment was organized as a split-plot design. The
main plots consisted of two PRSV inoculation methods,
i.e., manual inoculation versus aphid inoculation,
and the subplots consisted of three papaya genotypes,
including theR0 transgenics 55-1 and 62-1 and the nontransgenic
‘Sunset’ seedlings. Each of the six treatments
(2 methods of inoculation 3 genotypes) was
replicated ten times, with one plant of each treatment
per replicate. The 60 test plants were arranged in ten
rows (reps) with 3 m between rows and 2 m between
plants in each row. The test population was surrounded
with border rows consisting of non-transgenic cv.
Waimanalo seedlings. Non-transgenic seedlings were
planted on 11March 1992, andmicropropagatedtransgenic
plants were planted periodically from 11 March
1992 to 1 July 1992, as they became available from tissue
culture. All aspects of the field trial were executed
according to the plan detailed in our application for
environmental release (APHIS Permit 91-253-01).