wild crossings

As we all likely know, there is a lot of misinformation surrounding gardening and such.  Many things are easily brushed off as nonsense, and much needs a bit of knowledge &/or experience.  One of the things I've been told is to beware certain plants can cross with poisonous wild ones, and saving those seeds would be dangerous.  I'm fairly certain this is bunk.  Possibly whispered around long ago trying to stop people saving their own and instead, buy all their seeds.
Anyone know more about this?  I'm not concerned about 1-in-a-billion chances. Are there any plants with a reasonable possibility of doing this?

Squash can, people have even died from it and it doesn't need to be a "wild" version it crosses with either if anyone is growing an ornamental squash and that crosses in then you can get a poisonous squash plant, I believe it is theoretically possible to reactivate the genes for the poison without crossing to a wild or ornamental plant but that is much less likely. The good news is the poison causes the plant to be horrendously bitter, so bitter that few people are going to eat it. Last year (2020)  one of the major seed suppliers who supplies many of the UK's large seed companies had a problem with a cross and had to recall and issue warnings for several different seeds.

Courgette seed recall
German killed by Neighbours courgette

I have been growing landrace squash for more than a decade. In all that time, I have only found one squash with a hint of bitterness (poison) about it. That squash was an interspecies hybrid. I didn't replant seeds from that particular squash, and the trait never showed up again.

Pepo squash are the only commonly grown species that has readily available poisonous relatives.

In the other squash species, the genes for bitterness were eliminated millennia ago. Cross pollination doesn't create new genes for manuacturing poisons.

Thank you for your replies, good to know.
Pepo have always done terribly here anyway.  I finally gave up a few years back when the vine borers wore me down.  My 'mostly-butternut' feral moschata might not be the prettiest, and I don't care; she keeps us fed.  Reliable and delicious.

Usually this kind of warning comes from non-plant people.  Yet, once, I remember an oldish farmer tell me my beans would be poisonous, and some other ridiculous sounding bs.  Didn't stop me, its just rattled around in my head since then.

Anna Merkwelt wrote:once, I remember an oldish farmer tell me my beans would be poisonous, and some other ridiculous sounding bs.  Didn't stop me, its just rattled around in my head since then.

Beans are poisonous under the best of growing conditions. That's why traditional cooking methods call for long periods of soaking, and cooking for a long time at high temperatures.

One of the things I've been told is to beware certain plants can cross with poisonous wild ones, and saving those seeds would be dangerous.  

Hadn't heard of that one. Usually I just get people telling me that seeds from a hybrid are always sterile.

There are a few cases I remember reading about where people grafted vegetables onto stems from poisonous wild relatives. The one that sticks out the most was a tomato branch that had been grafted to a jimsonweed plant. The poison ended up in the fruits. The whole family had to be rushed to the hospital, where one died and the others had a long, difficult recovery.

(Going entirely by memory there.)

Joseph Lofthouse wrote:

Beans are poisonous under the best of growing conditions. That's why traditional cooking methods call for long periods of soaking, and cooking for a long time at high temperatures.

Well yes, fair enough.  He thought more so.  Pods and all.
Occasionally I've wondered if he was pulling my leg or trying to make a joke.  With this and other odd bits of wisdom.  He seemed genuinely concerned I might poison myself.

Ellendra Nauriel wrote:

Hadn't heard of that one. Usually I just get people telling me that seeds from a hybrid are always sterile.

That one's definitely well entrenched.

Lots of "wild plants are poisonous" fear gets passed down, so someone might have told him as a child and he never thought it might be false.

Ellendra Nauriel wrote:

There are a few cases I remember reading about where people grafted vegetables onto stems from poisonous wild relatives. The one that sticks out the most was a tomato branch that had been grafted to a jimsonweed plant. The poison ended up in the fruits. The whole family had to be rushed to the hospital, where one died and the others had a long, difficult recovery.

(Going entirely by memory there.)

Dang.

grafting a tomato to a jimsonweed sounds quite nefarious

I'm new to the forum and have wasted far too much time reading threads today, but have a question bugging me. Could my sweet potato (Ipomoea batatas) that blooms profusely cross with the related and edible wild potato (Ipomoea pandurata) that grows in my yard?

Welcome Katie.  I have grown sweet potatoes next to many other verities of potatoes and never had a problem crossing.  Hopefully someone will know here.

I feel wild crossings are only a concern if a person is growing many variations of the same plant.

Using the example that has been given for squash.

I have grown yellow crookneck squash, zucchini, cucumbers and acorn squash without any problems.  I have read someone saying on the forum that they had a variety that crossed with something else though it was still edible.

If something taste bitter then maybe that is something that would be best composted.

We have had some really strange stuff happen to our corn though we only grow one variety at a time.

Who knows what happened?

I see no good reason to stress over something that is beyond my control.

Following advice and direction on seed packets has always worked for me.

Katie and Christopher, it is very unlikely that sweet potatoes (i batatas) will cross with wild sweet potatoes (i pandurata) While they are related, they are different species. I have actually attempted that cross and failed.  Researching for my work with sweep potatoes, I found scholarly articles referencing the topic. Don't ask me to quote them as it was years ago, and I don't have them handy. I remember reading on experiments with pandurata as well as other members of the ipomea family. There are lots of them, morning glories, bindweed and even some that also make large roots. None of it worked or at least not without considerable effort on the part of the researchers.

Most of those articles were well above my pay grade anyway and I gave up on the notion of an actual perennial sweet potato. If a cross between the species was successful it might be a case where the hybrid really was sterile or the seed might need something like embryo rescue just to get it to live. Stuff like that is way, way over my pay grade.

Sweet potatoes and potatoes have nothing in common except the name, so they are not going to cross. Potatoes are related to tomatoes. I have never worked with those species, but I've read of folks who are working to make a plant that makes eatable tomato fruits and eatable potatoes on the same plant. I don't know the current state of their work.

As far as crossing with poisonous wild things goes that worries me some mostly because of my lack of knowledge. Here we have lots of Queen Ann's Lace, a wild carrot but it isn't poisonous, so I don't worry too much about it. But we also have lots of what I think is wild parsnips, which I understand is badly poisonous. It might be fine if I knew more about it but as is, I would never save parsnip seeds.



 

Hello Katie, Welcome to Permies!
I guess the question is do you want them to cross? They are obviously fairly closely related, but may not cross naturally. You could try doing some pollen transfer yourself and see what the offspring are like. People have crossed plums with apricots to get intermediate species, so I guess this would be similar.

Hi Mark,

I think you can drop the fear of wild parsnips. The only way they would cross with domesticated ones are if they are the same species (Pastinaca sativa) which is edible whether wild-growing or cultivated. (The leaves do have phototoxic effects though, so getting plant sap on exposed skin on a sunny day is potentially unpleasant. This, again, applies to both wild and cultivated plants.)

I remember a wild-foods book I read (can't recall which one, it was a few years ago) taking the wild/domesticated parsnip thing as an example of the fear-mongering bs often found concerning the eating of wild plants. Apparently, some "sources" claim that P. sativa plants were lethally poisonous growing in the wild, but turned edible once cultivation started. This begs two questions: Why would people even attempt to cultivate something that poisonous for use as a root vegetable, and how would a given parsnip plant know if it was "wild" or "cultivated"? Of course selective breeding can gradually remove nasty chemicals over the course of many plant generations, but who in their right mind would start with something that's lethally toxic and try to make it edible?

Also, since you are in America, P. sativa is not native in your area, meaning that if you have wild P. sativa around your place they are the descendants of cultivated parsnips gone feral, so you don't even have to worry about the slight risk of potentially harmful wild genetics (such as in the squash example). Even in Europe, I believe most "wild" parsnips have cultivated ancestors.

It's possible that this whole issue started with a misunderstanding regarding common names vs scientific names. For example, Cicuta virosa (water hemlock, highly poisonous) is also known as "poison parsnip". So maybe someone thought Cicuta virosa is wild parsnip, despite being not only of a different species, but of a different genus. Let this initial misunderstanding steep for a bunch of decades, and you end up with the common "truth" that wild parsnips are poisonous. Maybe.

Anyway, the only way your wild parsnips would cross with your domesticated ones is if they are indeed Pastinaca sativa, in which case it's completely safe to eat the descendants (although they would of course be of a different variety than the ones you started with). If the wild "parsnips" are some other, potentially poisonous, species, they won't cross.