Planting 1000s of seeds from the cold hardiest avocados (experiment)

[drymifolia]

So besides the tex-mex avocados does anyone have any interest in importing more drymifolia/criollo genetics?

It is basically impossible to legally import any avocado material other than the fruit, and then only "Hass grade" fruit via a licensed importer. There is no clear way to get a permit or exemption, and I looked a lot, but I'm no expert.

Here's a nursery in WA doing trials with criollo (idk if related to drymifolia)
https://johannsgarden.square.site/product/persea-americana-var-drymifolia-almost-hardy-criollo-avocado-aguacate-criollo/423?cp=true&sa=false&sbp=false&q=false&category_id=3

Johann isn't officially affiliated with our project, but he donated budwood of the parent tree to those seedlings, which is named "Linh" after the person who has the ortet growing in their yard. The main graft is growing nicely on one of our multi-graft trees in the greenhouse, and interestingly it has been the slowest to bud out this spring out of all the dozens of cultivars, but no flowers this year:

I don't know about in the US but if someone really was invested then as another user said they could do something akin to what Kumin is doing for citranges by buying rootstock seed wholesale, planting and looking what survives and variation among them:

https://www.viverosblanco.com/en/rootstocks - mexicola and "water-hole" seed

That second one is a typo, it should be "Walter Hole," which is one of the varieties available from the UC Riverside collection, and is flowering for the first time this spring on one of our multi-graft trees. Here's Walter Hole a few days ago:



Here's the list of UC genetics, which includes a number of Mexican cultivars not generally available in the trade:

http://ucavo.ucr.edu/avocadovarieties/VarietyFrame.html

[Pandan]

Apparently persea seeds can be mailed here but basically all latin american nations are on a ban list

Are there any scions you want but havent attained yet? Like a rumored cold hardy tree or others among the 'tex mex' criollos

[drymifolia]

Apparently persea seeds can be mailed here but basically all latin american nations are on a ban list

Are there any scions you want but havent attained yet? Like a rumored cold hardy tree or others among the 'tex mex' criollos

Oh yeah, I meant from Mexico specifically, since that is the main place you'd find old specimens in cold parts of the northern highlands that may have never been included in the historical introductions that were focused more on fruit quality than cold hardiness.

For the moment, I've gathered more cultivars than I will be able to fruit in my greenhouse, so until I start culling or other members with greenhouses in this area dedicate space to the project, I'll probably take a break from adding more. One of the latest is a cultivar originally found growing in Brissago, Switzerland, so I'm excited to see what that will be like.

[lajos93]

https://www.viverosblanco.com/en/rootstocks - mexicola and "water-hole" seed

That site looks promising

That second one is a typo, it should be "Walter Hole," which is one of the varieties available from the UC Riverside collection, and is flowering for the first time this spring on one of our multi-graft trees. Here's Walter Hole a few days ago:

@drymifolia , would you agree that starting with Walter Hole / Mexicola seeds would be of the best way to do this?

[drymifolia]

@drymifolia , would you agree that starting with Walter Hole / Mexicola seeds would be of the best way to do this?

I'd say the broader the gene pool the better, but if those are the ones you can get in bulk then that's a good enough start probably.

So far for me, seedlings of Mexicola Grande, Duke, and Aravaipa have all been more hardy than those of Mexicola. I have never grown a seedling of Walter Hole or tested a graft of it outside, so I don't know how it compares. Hopefully it'll set one or two fruit this year so we'll start gathering data on it in a couple years when those get planted out.

My hardiest graft outside has been "Pancho" aka "Poncho" which is budding out and has no leaf damage after a winter low of 17°F (-8.3°C), though it was protected with an unheated upside down flower pot. I recommend including Pancho in any breeding pool.

I believe Fruitwood Nursery will ship internationally with phytosanitary certificates if you ask them to, so honestly if I were you I'd sign up to be notified when Joey, Mexicola, Mexicola Grande, Poncho, Fantastic, and Stewart are available, then fill a greenhouse with fruiting trees so you can plant out hundreds of seeds per year forever. That's my plan, at least! Though we'll need more greenhouse space to get to "hundreds" probably.

[Jabba The Hutt]

Or 10 thousands of seeds from the hardiest of avocadoes of all times (Joey, Fantastic, Lila etc.. )

Can we go down another half a zone maybe to reach Zone 7b, or a solid Zone 8a plant with natural selection and 7-10 years?
Is anyone doing this already?

If you plant 10 of thousands of seed it will show results in 10 years or less .With that many seed you will skip the decades!!

High oil content please!!! The guacamole is supposed to be thicker than salsa not more watery. Also why stop at 7b? Make sure you breed for cold hardiness down to zone 6b...

These are the needs of the people and definitely not my own selfish desires

[pagnr]

lajos93. can you remind us as to what Avocado variety seed you already have, or are able to access from fruit in local shops., or other European shops.

[lajos93]

@drymifolia

Actually I managed to get some hardy named varieties, so Im just about doing what you are doing, getting most of them to fast as quick as possible, then plant the seeds
In the meanwhile I wanna get another 10000 from seed vendors if possible

[lajos93]

@pagnr
im usually buying hass from the store, I planted about 28 plants in a small garden. now only 9972 to go 

[Enkis]

You might be able to use those hass seedlings as rootstocks in case they turn out not good for cold temperatures. According to this research:
https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&btnG=#d=gs_qabs&t=1682008768297&u=%23p%3D-F5DJvbfYlEJ

You can use cold tender avocados as rootstocks if the graft union is buried 4in below. This was done in Gainesville, zone 9a. However i never did this myself and i wonder if you can suffocate the roots if your soil is not loose enough

[drymifolia]

You might be able to use those hass seedlings as rootstocks in case they turn out not good for cold temperatures. According to this research:
https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&btnG=#d=gs_qabs&t=1682008768297&u=%23p%3D-F5DJvbfYlEJ

You can use cold tender avocados as rootstocks if the graft union is buried 4in below. This was done in Gainesville, zone 9a. However i never did this myself and i wonder if you can suffocate the roots if your soil is not loose enough

I've only done this a few times, seeds started indoors winter 2020/2021, bench grafted very low in early summer 2021, planted as soon as the grafts took.

Two of them were planted with grafts about 3-4 inches below grade, the third one was planted with the graft right at ground level, but heavily mulched before winter. The winter low was 16°F (-8.9°C), which occurred when the trees were under a few inches of snow.

One of the grafts (Joey) showed living stems well above ground level through winter and until middle of spring, when the whole thing slowly desiccated. When I dug it up, you could clearly see the roots below the graft were more dead than the stem above. The roots were killed despite being deeply buried.

The other two (Winter Mexican and a mislabeled Poncho from Fast Growing Trees that was likely also Winter Mexican) died above and below ground. No new shoots from the roots in spring. I think soil/subsoil temperature matters a lot, and many of the less-hardy avocados seem unable to withstand our long, cool winters, even when the roots themselves never fall below freezing. Our soil temperatures here are likely 20 degrees or more below the same zone in north FL, but very rarely freeze solid more than an inch below the surface.

By contrast, here's a seedling of Mexicola Grande that's already budding out after two straight winters unprotected (16°F & 17°F minimums), these roots survive very well even though you can see the remnant stem from the first winter and last season's trunk that's already dying back above this bud:

[Pandan]

Found a criollo nursery in Houston (zone 9a) idk if they mail
their page specifically mentions cold hardiness

https://www.facebook.com/criolloavocado/


I also did some research on those heirloom varieties from that first link i posted in this thread.

[Enkis]

@drymifolia
Thanks for sharing your experience. That's unfortunate because i was hoping for this to work as for me also it's much easier to find hass avocados seeds. I will give it a try anyway but guess i will have to think of other solutions as well

[drymifolia]

@drymifolia
Thanks for sharing your experience. That's unfortunate because i was hoping for this to work as for me also it's much easier to find hass avocados seeds. I will give it a try anyway but guess i will have to think of other solutions as well

I wouldn't discourage it, for sure. Mine could have failed for other reasons (soil chemistry, moisture, pathogens?). And not all "Hass" fruit are from the actual cultivar, others like Lamb are also sold as Hass, not to mention the fact that some orchards may use hardy cultivars as pollenizer, so a better percentage of those seeds would be hardier too.

[lajos93]

@drymifolia
Thanks for sharing your experience. That's unfortunate because i was hoping for this to work as for me also it's much easier to find hass avocados seeds. I will give it a try anyway but guess i will have to think of other solutions as well

Actually this guy gave me the idea. According to him, Hass avocadoe seedlings do have the potential to be very cold hardy, lets say 1/100
https://georgestancliffe.medium.com/the-b-c-avocado-project-670ed22a74d7

[drymifolia]

@drymifolia
Thanks for sharing your experience. That's unfortunate because i was hoping for this to work as for me also it's much easier to find hass avocados seeds. I will give it a try anyway but guess i will have to think of other solutions as well

Actually this guy gave me the idea. According to him, Hass avocadoe seedlings do have the potential to be very cold hardy, lets say 1/100
https://georgestancliffe.medium.com/the-b-c-avocado-project-670ed22a74d7

I've tried to get better info & photos of his alleged survivors from George when he has posted about it on other fruit growing forums and he never responded. I'm extremely skeptical of his claims. I'd love for him to back up his claims with better photos showing the base of the trees that allegedly survived, it should be very easy to determine whether they actually regrew from winter damage or were planted outside in the spring and claimed to have been out all winter.

I've planted hundreds of hardy seeds and dozens of Hass seeds and I think it's extremely unlikely for a Hass seedling to be as hardy as he claims that one was unless he just lucked out with a 1 in a million seedling.

[Enkis]

@drymifolia
Thanks for sharing your experience. That's unfortunate because i was hoping for this to work as for me also it's much easier to find hass avocados seeds. I will give it a try anyway but guess i will have to think of other solutions as well

Actually this guy gave me the idea. According to him, Hass avocadoe seedlings do have the potential to be very cold hardy, lets say 1/100
https://georgestancliffe.medium.com/the-b-c-avocado-project-670ed22a74d7

If it's 1/100 we would already have plenty of non pure mexican hardy varieties by now. Even george in that article says it will take years.

[lajos93]

I've planted hundreds of hardy seeds and dozens of Hass seeds and I think it's extremely unlikely for a Hass seedling to be as hardy as he claims that one was unless he just lucked out with a 1 in a million seedling.

Wait youve already tried this with no success? Planting hundreds of seeds??

Ive read some success stories of a random seedling surviving in the compost in zone 8 climate I think

[lajos93]

@drymifolia

He answered to me in chat that hes no longer able to do the experiment due to personal reasons but he knows some guy who is doing it seriously . not much to work with

[lajos93]

If it's 1/100 we would already have plenty of non pure mexican hardy varieties by now. Even george in that article says it will take years.

Originally pomegranates were also subtropical. This should mean something, it does for me lol

[drymifolia]

I've planted hundreds of hardy seeds and dozens of Hass seeds and I think it's extremely unlikely for a Hass seedling to be as hardy as he claims that one was unless he just lucked out with a 1 in a million seedling.

Wait youve already tried this with no success? Planting hundreds of seeds??

I am in a cool zone 8b, so keep that in mind when you read the following.

At this point I've killed about 40 Hass seedlings (the "dozens" I referenced), and a handful of other non-hardy seedlings like Lula, Choquette, Sharwil and GEM. I call that section of my yard "Death Row" because they have so far had 100% winter death rate (both above and below ground).

For hardy seedlings, in my first winter of the project (2021/2022), I planted about 30 Mexican-type seedlings outside, seedlings of Mexicola, Mexicola Grande, Bacon, Purple Nebula, and Royal-Wright. Two thirds of them were killed completely, above and below ground. Nine survived below ground and regrew.

This winter, I planted another ~30 seedlings in my yard, seedlings of Duke, Mexicola, Aravaipa, Purple Nebula, and Royal-Wright. It is too early to be sure, but the survival rate seems similar to the previous winter, with some that survived last winter apparently dying this winter, but a few with stems alive above ground.

I kept about 50 trees in containers this winter, and let those get a few mild frosts in the fall to cull the most sensitive before moving them to the greenhouse for the coldest time of the winter. Nearly a dozen of these hardy seedlings suffered significant dieback from ~27°F, and most of them had some leaf or stem damage.

I have nearly 100 new hardy seedlings this year, and about 20 rooted cuttings.

So, "hundreds" may have been slight exaggeration, but I have a pretty good idea of the hardiness of various seedlings at this point, and Hass seedlings are not very hardy.

Ive read some success stories of a random seedling surviving in the compost in zone 8 climate I think

Yes! You're probably referring to Mike, who found a seedling in his compost in southern England. I'm in regular contact with Mike, who posts photo updates on his trees here:
https://imgur.com/a/5gflnlU

His location may technically be zone 8, but really closer to zone 9. Most winters since that tree sprouted he has not seen temperatures below -4°C (25°F), and he hasn't updated that page after this current winter, where the tree suffered significant dieback based on an email he sent a month ago. Here's a relevant excerpt from the email:

We had an unusually cold winter - four separate cold snaps, snow & ice laying permanently for 10 days for the first snap in December 2022. So, though disappointing, it came as no surprise that the almost 6-year-old 'Hass' has lost 90% of its leaves.  In addition, there's a good 20-25 cm of dieback from the tips of the uppermost branches (the most exposed). The lowermost lateral branches, which are closest to the ground, are injured less, as you'd expect.

That tree has still barely faced full zone 8b temperatures, let alone 8a or below, and it would probably die if it did.

[Enkis]

This nursery also seem to produce large quantities of plants. They have Zutano between their varieties.
https://www.viverosbrokaw.com

[Bush2Beach]

Probably one of the largest commercial Avocado nurseries in the US.

This nursery also seem to produce large quantities of plants. They have Zutano between their varieties.
https://www.viverosbrokaw.com

[Enkis]

Probably one of the largest commercial Avocado nurseries in the US.

This nursery also seem to produce large quantities of plants. They have Zutano between their varieties.
https://www.viverosbrokaw.com

It's located in Spain

[drymifolia]

Probably one of the largest commercial Avocado nurseries in the US.

This nursery also seem to produce large quantities of plants. They have Zutano between their varieties.
https://www.viverosbrokaw.com

It's located in Spain

They are a multinational company with large commercial nurseries in the U.S., Spain, Mexico, and likely other places too.