Although Papaya grafting is not possible , still if at all it is to be tried then papaya seedlings would have tobe taken as rootstock

I did grafting on conventional papaya rootstock grown from seed with more than 90 percent successful. What I'm looking for is an alternative rootstock for root disease control. Or to avoid "wet feet" where it grow in a low land situation. 

Reps about are available from ARCC arccjournals.com/uploads/articles/R1418.pdf but the need of  a riparian root stock is on the board.

The one that is well adapted to local soils and climate

Dear Klinkong

Please find attached papers.

Thank you.

Papaya grafting has been most successful in greenhouse environment and indoors also, if the temperature, sunlight and water needs of the plant are satisfied. 12-Inch pot container is sufficient for grafted plant. Papaya root stock grown from seeds have more than 80 to 90 percent success.