With regard to reduction in disease severity it can be speculated that the hot water treatment brings about changes in the pathogen that make critical systems e.g. nucleic acids and active proteins, more susceptible to radiation effects, at least over the time course of the study undertaken.
A significant, additive effect would be the net result.
The reduction in disease severity will also reduce the production of lytic and toxic compounds by the pathogen, aiding the retention of fruit quality.
It is also possible that lytic enzymes, for example, involved in fruit ripening are altered in some way by the heat treatment that makes them more susceptible to radiation effects.
Papaya is not seasonal in the region where the study was conducted, in that it is produced all year round under conditions of typical, equatorial
temperature.
There are rainfall differences, with a wet and dry season, but this has no significant impact on fruit size although it can affect early fruit drop (Masri et al., 1990) The effect on fruit pulp quality has not been reported.
To validate the combined method reported here there is obvious value in looking at fruits across the year, and in larger quantity