Papaya ringspot virus is the major limiting factor to production of pawpaws in many countries. There is a GM “solution”, but there’s now news that after 50 years of trying researchers have transferred resistance by conventional breeding from a wild relative, Vasconcellea quercifolia. I ran this by a colleague who’s an expert on papaya taxonomy, genetics and breeding and he had this to say:
I am very happy that they seem to have succeeded in their long and difficult work. And this is excellent news for all developing world papaya growers. GM was not the right solution because each virus strain implied a costly transformation (including patent rights), and the virus is highly variable.