Papaya is a short-lived perennial crop. Under ideal conditions, the trees begin to
bear fruit within months of planting and continue profitably for three
years. This provides a valuable non-stop
harvest.
The greatest single threat to papaya production globally has
long been considered papaya ringspot virus (PRSV). This rapidly spreading disease devastates
yield and fruit quality. In the absence
of any naturally-resistant strains for conventional breeders to tap into,
genetic transformation is viewed as "the most effective approach to
prevent and control PRSV". The
favoured GM trick is to insert a vital PRSV gene into the papaya which has the
effect of silencing that vital gene in the virus.