For anyone wanting to learn more about this breeding technique, it's called backcrossing[1]. It's also used for agricultural crops, but requires many generations.

[1] https://en.wikipedia.org/wiki/Backcrossing

Simple, yet effective. I've heard it said modern fruits are relatively tasteless compared to their older counterparts because they are bred for size and hardiness. I wonder if these can be backcrossed as well to produce more flavorful fruits with similar sizes

I imagine soil quality and time of harvest also play a decent part in taste. All other factors being equal picking a green tomato isn’t going to be as good as letting it ripen on the vine naturally.

Terroir is the term for this. It's variation in flavour isn't as great as varietal/strain based differences. But yes it does have some impact most commonly taken advantage of in wine production.

Interesting. I love nuts of all types, but not the chestnut. It's really more like a small potato than a nut. I wonder if the old ones tasted better.

Fresh they taste almost like sweet corn, I got to try a few American chestnuts last year, they are sweeter (but smaller) than the chinese chestnuts. My landlord boils the chinese one and eats them like mashed potatos, I roast them in oven or air fry them. To me they are like bread from the trees.

The English ones are starchy I guess? These are common to see in grocery stores when in season.

Also handling changes how sweet they get, some say they must be chilled in fridge for some days to get starches to convert to sugar. For me the Americans are perfect no matter the treatment. Chinese chestnuts I'm fighting getting to them fast enough before any mold grows, processing them immediately to kill chestnut weevil (I use a sous vide and let them sit at whatever temp the rutgers publication suggested to kill potential eggs) then I dry and fridge them for a few days before putting them in oven/airfryer. It sounds like a pain in the ass but it's a lot easier and less foul than the year I gathered and processed gingko seeds (which smells like dogshit) or even black walnuts which will stain your hands for over a week if you don't know to wear gloves.

Another protip: Don't plant a chestnut tree near a swimming pool. Those spines are sharp enough to pop a bicycle tire and the catkins smell like a callery pear when it's dumping pollen which is pretty gross.

That does sound like a lot of trouble. Yeah, "starchy" does describe my experience of them.

I had to look up "callery pear"

https://mortonarb.org/plant-and-protect/trees-and-plants/cal...

Dude I have just the recipe for you. Come on down to Chile and ask for puré de castañas. The really oppressed Chilean women make it the best, it's highly unique, I actually thought I could eat a chestnut because I used to eat this dish, kept biting into absolute bitterness. But bitter isn't bad, now that I'm addicted to something bitter (an undisclosed stimulant) I prefer bitterness to sweetness, but not everyone can be an addict, the addiction doesn't always take. Too bitter. Just like the American Chestnut didn't always take. Too bitter.

Love the bitterness. And in the dish there's a trace bitterness natural to the chestnut left in the puré, which involves sweetening chestnuts and also some I think crema Chantillí or leche condensada not sure which.

.

Let me add that in my unique Chileanized upbringing, as an American, a Chilean woman, in this unique case not oppressed, explained to me why I couldn't eat a cactus fruit, what's it called, tuna (no relation to fish in absolutely any way). So typically, she explained, gringos bite it wrong. They think you gotta bite it till your jaw closes, your teeth meet up again after that long goodbye when you put the fruit in your mouth. No, you gotta close your teeth less, not chew, no no, and she explained it to me in plain Spanish in a way I, a Chileanized American, a gringo, a gringuito (and in fact there was a movie about a Chileanized American called El Gringuito in the late 90's in Chile, huge hit), how to eat the native fruit. But I was a kid. This partial chewing made it good to eat, I can vouch. They would never tell you to only chew partially of politeness. But I can. I'm passing that on, to eat tuna fruit, work on your bite, don't bite all the way, like almost. Because it has a lot of seeds, very hard seeds, you see, so biting it all the way hurts, so you hate it.

Like bitterness. Great flavor, in fact.

I'm hungry now.

I'm sure chestnuts can be good in lots of ways, but "nutty" isn't one of them.

> The really oppressed Chilean women make it the best

Actually fuck this.

I know it sucks. But I'm taking the first step and saying they're oppressed, which they are.

I don't know why things in Chile work the way they do. I wasn't born here. I'm a guest, basically. An immigrant, got naturalized.

just needs a little butter and salt

For an example, the red delicious apple. 75% of the Washington state's apples in the 1980s. It was bred for color and shelf life and, in the process, they bred out the taste. In 2000, a congressional bailout was approved for the growers that had lost $760 million dollars over a 3 year period due to the now-worthless apples.

Hawkeye is what Red Delicious used to be. You can still find it grown by smaller orchards around the country.

Most modern apple cultivars have a lot more taste and flavour than red delicious

The hard thing with taste is that it's usually the sum of many quantitative traits, each one being governed by several genes which can be located on different chromosomes, as seen in tomato[1]. Transferring enough of them into the modern genome through backcross would probably require a crazy amount of generations... or a crazy amount of luck :)

[1] https://doi.org/10.1093/jxb/erf058

You would need to map the relevant loci and then use a speed congenic selection strategy. Done in mice easily. Mapping the loci modulating traits like disease resistance or taste is the hard part.

Or, you know, CRISPR.

CRISPR as currently used is not functionally capable of cutting and pasting large swaths of the genome, it is for small specific edits

That's not true

If you ever see a cannabis strain name with a Bx in it, it stands for Backcross!

Saw that video recently as well. What's remarkable about this find is the size of the specimen, and that it's confirmed to be 100% American Chestnut. Hopefully with the hybrid approach, this find, and further breeding/propagation work, we can see a large scale return of this incredible species.

Why don't they use agrobacterium transfection, gene guns, or molecular techniques to directly transfer the resistance genes over? Do we not know what the genes themselves are?

I'm not criticizing their technique! Nor do I think I know better. This is amazing and valuable work, and I'd love to know more.

There is actually a parallel technique nearing the finish line that does sort of this. The gene they moved though is from wheat not another tree species, but still seems to give great blight resistance. Currently the barrier to it is entirely regularity. I believe it would be one of the first plants approved to just be released into the wild without something to prevent it reproducing naturally. The normal anti genetic engineering types are very opposed, but it seems likely it will get approved in the next few years.

https://www.nytimes.com/2020/04/30/magazine/american-chestnu...

What authority can enforce approval or disapproval to release something into the wild? Suppose I own land next to a national park. Then can’t I plant whatever I want on that land, trusting that it will spread into the park?

These are not GMO plants—just selectively bred plants. This is similar to almost all domestic animals and most plants.

There are two parallel efforts going on at present for restoring the American chestnut, a backcross effort and a GMO-based approach. This sub-thread is concerned with the GMO strategy.

A buddy of mine has been involved in this project for years at SUNY ESF, and it's very exciting how successful it has been. There are dozens of test sites around central New York that have healthy (albeit very young) populations of American Chestnuts.

I've been wondering the same things for the past decade. It seems like it's very hard to get your gene into the right place so that it will be expressed at the right time, with enough consistency to make a stable cell line.

Also, it seems rare to find just one gene that encodes a property or compound. Usually you need several genes to form a pathway from a common precursor chemical to your target result. That pathway will be leaky, and it may take resources away from other important chemicals that the plant's lifecycle relies on.

It sounds expensive and time consuming - plants take a long time to compile, and you can forget about reproducible builds. Plus, once you have your GMO, you'll be expected to take care not to release it into the wild, and in today's world, a decent chunk of people will oppose your product because of their personal beliefs.

Good question. I'd imagine something like blight resistance would probably not be a simple case of a few specific genes we can just switch over.

It could also just be technology. This breeding program has been around for 50 years or so and CRISPR only really took off around 2011. In addition, the original CRISPR-Ca9 caused a lot of unintended changes in DNA and it's really critical that the new trees are morphologically equivalent to the original trees in order for the birds, insects, and animals that depended on them to resume their interactions. Newer technologies like CRISPR-Nickase are much more precise but also very recently developed

It actually is pretty "simple" in this case (the tree needs to produce a single chemical, oxalate oxidase). There is a program that has done this very successfully, and it just working through the regulatory process before wider distribution can happen. They have thousands of trees in (controlled) forest plots, including three generations of offspring.

That's the genetic engineering approach, but the Chinese ones have a different, more complex, less well understood, and potentially complementary resistance mechanism.

Right, the genetic engineering approach is what this reply thread is about…

That's very interesting. The video I linked showed that blight resistant trees had a very specific response to grow extra tissue around the infection site to stop it from spreading further so I assumed it was more of a multi-pronged defense

Yes - the Asian ones that evolved with the fungus have a more complex strategy, making a purely breeding-based program challenging. Separately, some clever genetic engineering allows the trees to break down oxalic acid, which prevents the fungus from being able to efficiently attack the plant cells.

Two separate things.

These two approaches could be combined, and probably will be naturally if both varieties are introduced to the wild.

Indeed, part of the work being done by the team working on the genetic engineering approach is breeding Darling 58 with the Chinese backcrossed version.

The things the gene gun can do turn out to be not the most useful things one could hope for from it. (It's a surprisingly brute-force device, though I guess that was all in the name if you actually took it at face value!) I don't see a ton of future for it as a generalist technology, though what things it does well it does very well.

CRISPR is... awful in different ways. (It seems to have a lot of trouble controlling how much material it transfers.) It's a laboratory curio or one-off stunt now, but I fully expect it will improve.

Honestly there's probably a benefit to just avoiding more controversial tech like GMOs. There will be that much less resistance to re-introducing them back into the wild

IIRC the breeding program predates those tools.

If I recall, someone has jammed a wheat gene into a few of them in just that manner.

It's a tricky business, because chestnut had very particular properties, as wood, that made it quite valuable, and any gene interference, well ... who knows how it will change the resultant wood?

Low-tech, non flash solution that delivers.

They probably have no firm idea about the key genes involved in resistance. There could be half a dozen.

There are methods like GWAS that could help nail that down.

Do we not know ....

Unfortunately, I can’t buy them yet. Driving me nuts

> Driving me nuts

I see what you did there.

You can buy the backcrosses, as far as I know...it's the modified ones from SUNY ESF that you can't buy yet.

You can actually buy them for 2023 - https://support.acf.org/membership/new-seed-level

But they still have to pass the FDA, EPA, USDA - https://www.federalregister.gov/documents/2021/08/06/2021-16...

The chestnut project is from the Commonwealth of Virginia, not West Virginia.

Woops, thanks for the correction

The genetic modification the ACF is doing is actually very controversial among the community of people commuted to restoring fruit and nut biodiversity.

I just saw Eliza Greenman speak on this subject, never expected that to circle back to HN.

Backcrossing/“breeding” is relatively uncontroversial and not considered GMO — though it may be controversial whether the eventual derived breed is a true American Chestnut.

There is a GMO effort which adds a gene to the American Chestnut so that it produces an enzyme called oxalate oxidase; the gene comes from wheat plants. The enzyme breaks down the oxalate acid produced by the blight fungus. The first GMO tree was planted in 2006 and has held up, as have others in the test plot. IIRC, USDA permission is being sought so it can be planted freely. Assuming it wins approval, I’m really hoping I can get some seedlings in a few years to plant in my forest.

https://www.esf.edu/chestnut/genes.htm

"To save the American chestnut tree, researchers want to release genetically engineered trees into the wild to reproduce. It would be a first — a possible breakthrough and an irreversible experiment."

https://acf.org/ny/news-events/how-gmos-might-save-the-ameri...

You can actually buy some of those seeds now - https://support.acf.org/membership/new-seed-level

Though, they are still going through the FDA, EPA, and USDA process...

https://www.federalregister.gov/documents/2021/08/06/2021-16...

I hate these awful GMO trees! Why can't we have certified USDA Organic trees anymore!

Assume this is a joke, right? Have to add the ;-) even for nominally bright people.

It's a joke, but I do have questions in general about "Certified Non-GMO" versus "Modern day bananas, corn and tomatoes look nothing like they did 400 years ago". There are some types of genetic modifications that are considered "natural" and "OK" and somehow there are others that are "artificial" and "scary", but damned if I know which are which.

To play devil's advocate to myself and possibly answer my own question: I imagine there are ecological effects of GMO (some of your corn SHOULD get killed by insects). Not to mention the fact that GMO seeds are probably mostly sold by god-awful Monsanto.

“No GMO” labeling isn’t because of any of those issues though; it’s just marketing to Green Meme people, upper class Whole Foods shoppers who are big into naturalistic fallacies.

There are two “no GMO” markets: the one you mentioned, and a much smaller market of people who object to GMO for pesticide resistance instead of GMO for disease resistance.

I don’t avoid GMO foods, but I do think our current scheme incentivizes finding the strongest poison and correcting the plant to resist it, without concern for how that poison affects the rest of the environment. I would much rather we engineer the plant to resist the disease directly, but it’s harder to double dip on profits (RoundUp and RoundUp Ready) in that scheme.

casual slander of people who can choose their food? The Organic Standard of the USDA is one of the great achievements of the modern times, along with the US Clean Air Act, Clean Water Act, establishment of the EPA and the Endangered Species Act. Organic foods standard was the work of thousands of people, companies and academics over a decade+. Small farmers have a chance to compete in niche markets as a relief from crushing food commodity pricing.

personal spite is misplaced, and ignorant actually.

https://en.wikipedia.org/wiki/Organic_certification

Maybe someone with an agricultural background would have an easier time researching this, but:

"mostly" Monsanto? Or is that just an older, famous example? Lots of companies sell seeds in mass quantities -- are you saying none of them sell GMO seeds?

That's why I said probably. I just know Monsanto is famous for their "copyright" seeds that are genetically modified and you're not allowed to keep the next generation of seeds.

They're famous for lots of bullshit they didn't actually do. It's part of the demonization process.

In this case, Monsanto never sold "terminator" seeds. They (and many others) sold hybrid seeds, which don't breed true, and so are functionally equivalent to that. Hybrid seeds have been around since the 1930s, if not earlier.

In any case, they can get the same effect by contract. You were not allowed to replant Roundup Ready soybeans, and they sued (and won against) farmers who broke the contract to do that.

They even won against farmers who signed no contract.

They won against a farmer who deliberately sprayed a field with herbicide to concentrate traces of the herbicide resistance gene that had drifted in. This was properly ruled to be deliberate violation of the patent. Nothing wrong with this.

Except the notion of patenting genes that infect natural seeds farmers must plant for next year's crop.

If the courts cannot see the distinction between farmers and plants violating patents, then the Congress may amend the law to oblige them to see it.

Thanks, that did have the odor of the urban rumor that someone "read this somewhere on the internet" and is now repeating one more time. Although he did admit his lack of sourcing.

nah, the whole ";)" "/s" "/j" nonsense can go yeet itself off a cliff. i absolutely hate that stuff.

Yoink that back.

I sent them an email asking them for seeds a few months ago, unfortunately they stopped giving them out.

Do you know if they'll resume giving them out at some point? Maybe someone else who got access to seeds can help you out