Cold hardy avocados ?

[shiro]

I'm opening this discussion to see if those with experience can answer me about some of the questions I have.

Among those who have cold hardy avocado what are the varieties of which you yourself have managed to observe a great resistance to cold?
And at what temperature ?

I read that aravaipa can resist to -12°C. Did any of you observe it ?
Same for the other Del Rio, Poncho, Joey.
Can a member assert by his observations their resistance to the cold mentioned by the various sources ?
https://toptropicals.com/html/toptropicals/articles/fruit/varieties_avocado.htm

In which condition, tree on its own root or grafted and if yes on which rootstock ( duke7, toro canyon ....) ?

Did any of you graft cold hardy avocados and less cold resistant avocados on the same rootstock. And did you manage to observe if the grafts of cold hardy avocados have transmitted by hormones and the rising and falling sap a greater tolerance to cold on the less resistant varieties ?

Grafted by approach 2 trees a cold hardy avocado and a no hardy can it make the whole more resistant to cold ?

I ask these questions in order to know if there is a method to increase the resistance of avocados not resistant to the cold in the same way as what is observed with citrus fruits.

thanks to those who will be able to answer .