I was searching through the forum and other places and I couldn't find any conclusive answers. This is what I could find from some quick research.
'Rainbow' and 'SunUp' are GMO papaya cultivars developed by the University of Hawaii and were released to Hawaiian growers.
The pollen drift from these cultivars infected a large percentage of other papayas grown on some of the islands. A lot of these were these Solo types.
You can test test papaya for GMO crossing with different gene testing. This goes into it briefly.
http://www.hawaiiseed.org/local-issues/papaya/Right now I am growing Improved Solo Sunrise, Linda, Hawaiian Solo Sunset and Waimanalo X-77 (Kamia) from alohaseed.com. The seeds were shipped from California but I have no idea where they were sourced from. I have purchased seed from them a couple times and I highly recommend them.
What are the chances that these papaya are non-GMO?
Does anyone know of a lab that does gene testing? Would it be way out of a decent price range? It might be worth it to develop my own verified non gmo papaya seedlings. There aren't any other papaya plants around my area.
I have heard that the Solo types are harder to grow in Florida but it can be done. What are the main issues with these in Florida? Maybe grafting to a different rootstock would help. So far everything is growing great here but they are still small and haven't flowered yet. They are also planted in highly modified soil in a root pruning raised bed with a compost pit in the middle so soil fertility and drainage won't be an issue.