Yes I reckon pure Mexican types are the best Lila can apparently survive down to -10 but struggles to hold its fruits - it has been documented for 6 years or so by the millennial gardener in North Carolina (zone 8b/a).A similar humid climate which could be another issue with fruit development as Mexican types are native to fairly dry climates and with there thin skins are more susceptible to fungus diseases etc but probably not the biggest issue😂
I reckon as hass types are 61% Mexican genetically and are possibly pollinated with a Mexican race variety a chance seedling could be quite hardy.
A documented tree that is 4 years old in British Columbia survived a -14 freeze but I can’t rerify that.I will probably be trialling as many seedlings as I can- obviously any grafted plants I’m not going to risk especially when they are only a few years old or so.
I think the idea of grafting a and b types makes sense -how do you tell them apart other than the fact that the male and female parts of the flowers open at different times?
Yes I have looked it the heat requirements of avocados to produce flower buds and there is pretty much zero research which makes sense as we have quite a unique climate in which we don’t get very cold or hot - even if you were breeding avocados to survive hard freezes in say northern Florida heat in the growing season would never be an issue.
I suppose that will slowly be solved by climate change anyway so having an established cold hardy tree in ground would be an advantage in itself but from the scientific papers on avocados I have seen the only documented requirement for flower buds to be produced is interestingly a cool period in autumn or towards the end of the growing season and this is variable - Mexican cultivars struggle to produce well in really warm areas like the Caribbean because of this.
I suspect that the GDD requirement is also variable depending on cultivar and is one of the easier traits to breed - think of evergreen blueberries in south Florida and peach with ~ 250 chilling hours and naturally you would expect the requirement for the Mexican types to be lower as they developed in colder climates.
I don’t know of any pure Mexican trees in the uk that have flowered but hopefully you can test this theory.
Fruitwood Nursery I think it’s based in California shops budwood worldwide with a £70 charge for a phytosanitary certificate and a little more for shipping the sell about 10 different Mexican race types and restock in late autumn they currently have a good few still available but I’m not considering it for this spring I don’t have enough rootstocks -I would like to order some other scions form them aswell.
I think it’s quite possible and with breeding over time will become easier.
Really interested to see your trees development this year -the bacon looks very promising.
Kind regards Joseph
