What plants can't reproduce without human assistance?

[Aspidistra]

I'm pretty sure bananas can't. From the wikipedia page:


Cultivated bananas are parthenocarpic, which makes them sterile and unable to produce viable seeds. Lacking seeds, propagation typically involves removing and transplanting part of the underground stem (called a corm).


Anything else?

[Schnitte]

Note that this cite doesn't speak about bananas in general, only about cultivated bananas. Many of the cultivated seedless breeds can't reproduce without human intervention, precisely because they are seedless - rather, each generation has to be bred or transplanted anew. But these breeds have specifically been created by humans; wild bananas can and do, of course, reproduce without human intervention.

[Broomstick]

Corn, zea mays, can not reproduce on its own. The ears are too tightly wrapped with leaves for the seeds to get out on their own.

[DrFidelius]

Most cultivars require intervention to reproduce. That's part of cultivation.

[Ionizer]

Corn, zea mays, can not reproduce on its own. The ears are too tightly wrapped with leaves for the seeds to get out on their own.

I challenge this heartily. According to USDA (http://plants.usda.gov/java/profile?symbol=ZEMA), it is/can be weedy/invasive (!) Who would be going around tossing the unwrapped seed to produce this classification? Are you saying that the very first corn ear had a person there to unwrap it so it could grow again? And repeat every year for how many centuries/eons? I toss my 'bad corn ears' (bug infested or just not worth husking) into a pile every year, and I *always* get corn sprouts the next year from the pile. I do not bother to husk the ears before tossing ;) Both Silver Queen and Peaches & Cream varieties have germinated a few sprouts minimum the next year without me unwrapping 'em at all, so I am sure that plain ol' corn would do so as well. Animals/insects might help unwrap the ears, but it does not require *humans* in any way (unless a specific cultivar is intent, which requires controlled pollination usually).

There are many 'cultivars' that require being cloned to continue the lineage since the seed does not form well enough to carry the genes to next generation. As example, seed from a Winesap apple generally won't grow a Winesap apple - probably would grow more as a crabapple-type apple. Cloning by cuttings, germ tissue, grafting, etc is how cultivars are kept from reverting (usually). 'Basic' varieties just keep on reproducing as Nature designed 'em to do.

[Dr. Drake]

The bergamot (http://en.wikipedia.org/wiki/Bergamot_orange) doesn't even exist as an independent plant, only as a graft onto other citrus stock. I'm sure there are many varieties of cultivated fruit for which that is the case.

[Colibri]

I challenge this heartily. According to USDA (http://plants.usda.gov/java/profile?symbol=ZEMA), it is/can be weedy/invasive (!)

I'm not sure what the basis of that classification might be. Certainly I've never known it to be weedy or invasive; I suspect this circumstance must be very rare if it occurs. Domestic corn is very frequently stated to be incapable of reproducing itself in the wild to any great extent. This is not only due to the tight husks, but also because the kernels adhere strongly to the ear and do not easily disarticulate. Whether or not domestic corn might not occasionally reproduce in the wild, it is very poorly suited to disperse its seeds.


Who would be going around tossing the unwrapped seed to produce this classification?

If wild reproduction occasionally occurs, I expect it is either because of spilled grain or because the ears have been opened and the seeds dispersed by animals.

Are you saying that the very first corn ear had a person there to unwrap it so it could grow again?

This is certainly the case. Maize as we know it is unknown in the wild; the first evidence of it is as an agricultural plant. For a long time its origin was a great mystery, exactly because its characteristics make it unsuitable for propagation without human assistance. It is know generally acknowledged to be descended, through hybridization (and perhaps with additional mutations) from various forms of teosinte (http://en.wikipedia.org/wiki/Teosinte), though even now the details are controversial.

[Markxxx]

Wow I never thought about it, but bananas have to be involved in a three-way (at least) to reproduce :)

[RealityChuck]

Navel oranges.

[Tapioca Dextrin]

Seedless grapes and melons (http://www.straightdope.com/columns/read/1075/how-do-they-grow-more-seedless-fruit).

[aruvqan]

Corn, zea mays, can not reproduce on its own. The ears are too tightly wrapped with leaves for the seeds to get out on their own.
Then what explains the random rogue corn growing in the woods on my place [and we haven't planted corn in about 15 years so it has to come from one of the farmers on the road]

[Quercus]

The bergamot (http://en.wikipedia.org/wiki/Bergamot_orange) doesn't even exist as an independent plant, only as a graft onto other citrus stock. I'm sure there are many varieties of cultivated fruit for which that is the case.Do you have a source for this? The Wiki article doesn't mention it and http://www.tradewindsfruit.com/bergamot.htm says "Propagation: Commonly by seed which usually produce trees very near in fruit quality to their parent. Also by grafts."


But aren't almost all wine and eating grapes grown by grafts onto rootstock of American concord grapes (a different species)?

[md2000]

I challenge this heartily. According to USDA (http://plants.usda.gov/java/profile?symbol=ZEMA), it is/can be weedy/invasive (!) Who would be going around tossing the unwrapped seed to produce this classification? Are you saying that the very first corn ear had a person there to unwrap it so it could grow again? And repeat every year for how many centuries/eons? I toss my 'bad corn ears' (bug infested or just not worth husking) into a pile every year, and I *always* get corn sprouts the next year from the pile. I do not bother to husk the ears before tossing ;) Both Silver Queen and Peaches & Cream varieties have germinated a few sprouts minimum the next year without me unwrapping 'em at all, so I am sure that plain ol' corn would do so as well. Animals/insects might help unwrap the ears, but it does not require *humans* in any way (unless a specific cultivar is intent, which requires controlled pollination usually).

There are many 'cultivars' that require being cloned to continue the lineage since the seed does not form well enough to carry the genes to next generation. As example, seed from a Winesap apple generally won't grow a Winesap apple - probably would grow more as a crabapple-type apple. Cloning by cuttings, germ tissue, grafting, etc is how cultivars are kept from reverting (usually). 'Basic' varieties just keep on reproducing as Nature designed 'em to do.

IIRC, the Scientific American article that traced he evolution of corn as a staple crop in the south USA/Mexico area mentioned that it could not grow in the wild.

Obvioulsy seeds properly placed will grow, and being trapped in the husk does not seem to stop most of them; but unless someone/something makes a point of hauling the ears around, it seem to me they sit where they grow. Maybe you get fairy rings of corn?

The article also traced the gradual evolution through selective cultivation - from a grass head with tiny kernels that spread in the wild just fine to progressively bigger and more tightly wrapped ears that did not disperse naturally.

SO the question is - does the local animal population present enough of a dispersal mechanism to let corn spread without human intervention?

[Dr. Drake]

Do you have a source for this? The Wiki article doesn't mention it and http://www.tradewindsfruit.com/bergamot.htm says "Propagation: Commonly by seed which usually produce trees very near in fruit quality to their parent. Also by grafts."


But aren't almost all wine and eating grapes grown by grafts onto rootstock of American concord grapes (a different species)?No authoritative source; I was told this by a bergamot farmer in Italy. Looking around online, I find http://www.agraria.org/coltivazioniarboree/coltivazioneagrumi.htm which says "Per prevenire alcune fitopatie che colpiscono l’apparato radicale si ricorre all’innesto" ["In order to prevent any of the diseases that attack the root system they resort to grafting"]. Elsewhere it says that the seeds are monoembryonic, which I gather has something to do with this. So apparently I was misinformed about their ability to grow from seeds, even if in practice it doesn't much happen.

[Broomstick]

I challenge this heartily. According to USDA (http://plants.usda.gov/java/profile?symbol=ZEMA), it is/can be weedy/invasive (!) Who would be going around tossing the unwrapped seed to produce this classification?
During corn harvesting it is entirely possible for seed to drop on the ground during processing. I suppose it is also possible for foraging animals to leave a few seeds behind and not have those seeds subsequently snatched by other animals.

Are you saying that the very first corn ear had a person there to unwrap it so it could grow again?
Yep. Modern corn is so far removed from its wild ancestor that it wasn't until we could analyze complete genomes that scientists could finally say with confidence that Zea mays is a descendant of teosinte. Corn was created by centuries of selective breeding by humans and the intermediate forms between teosinte and Zea mays have all been lost. Corn as we know it is entirely the product of human intervention.

'Basic' varieties just keep on reproducing as Nature designed 'em to do.
Sure - but Zea mays isn't a natural creation, it's a human production.

[Broomstick]

But aren't almost all wine and eating grapes grown by grafts onto rootstock of American concord grapes (a different species)?
Yes, but that is because of a disease imported from North America to Europe, not because European grapes are incapable of reproducing. The problem is that once they reproduce they have no resistance to the invasive pest

[Broomstick]

Then what explains the random rogue corn growing in the woods on my place [and we haven't planted corn in about 15 years so it has to come from one of the farmers on the road]
Could be dropped kernels during harvest, processing, or transport. Also some random transport by animals. It's not that corn never pops up the next year - I see random stalks in soybean fields all the time around here - it's just that it's so very inefficient at dispersal that no population is going survive in the wild without human activity.

[Mangetout]

Many plants with 'double' flowers lack essential reproductive organs and cannot therefore produce viable seed. Some of these can probably still reproduce on their own via suckers (shoots arising from the base or roots, capable of becoming independent plants), natural layering (branches touching ground and taking root), etc.

[Kimstu]

It's not that corn never pops up the next year - I see random stalks in soybean fields all the time around here - it's just that it's so very inefficient at dispersal that no population is going survive in the wild without human activity.

Yeah, it looks as though we need a clarification of the question in the thread title here. There are plants that literally cannot reproduce themselves without physical intervention by humans, as in the case of the seedless/grafted fruits mentioned above; and then there are plants that can physically reproduce untouched by humans, but not reliably enough to create sustainable populations, as in the case of maize/corn.

[Ionizer]

I just went and looked out in my 'trash plants' pile, and found several germinating corn seed :) It has been warm enough last few weeks or so to cause germination(s) of many things, and the corn is being compliant. Again. This morning's ice/sleet upon them certainly killed 'em, but they were living quite happily until then apparently. All I did was toss crappy ears atop other stuff to rot compost-style and Nature did the rest.

The OP asked about human intervention, and for the third year in a row, corn has popped up without me doing a thing for it. I would call that pretty reliable.

Interesting about corn being 'domesticated' and not just found in wild and taken/improved from there. Ignorance fought and off I go to read more on it. But I stand firm that it does *not* require humans to grow/spread on its own. Perhaps climate variances may make a difference in viability or such other than my Zone 7 location (shrug). I know corn won't grow well at all without a high-nitrogen soil so location makes a difference as well obviously. I have also seen plenty of stray corn growing along canals in south/central Idaho (11+ years ago) that in no way could've gotten there by humans unless some person went waaaay way outta their way to plant it (?). Rarely were many stalks present as the cold weather prevented it from getting thick - I presume that killed most seed keeping it from flourishing, and lots of corn was grown commercially along those canals to provide seed to spread by whatever means. Sometimes the canal was in middle of desert with no real roads around for miles nor any farming anywhere near (areas where I went hunting quite often). There was often 'wild' asparagus nearby them as well. Oh, I miss that near-unlimited free asparagus really bad nowadays.

Reading through a wiki article (and other/better sources too) on corn says that there is much uncertainty of modern corn's actual origin, so I guess it is fair to say that it is not really known for sure (right?). I will let others fight that part out as it makes no difference to me :) Corn is tasty and I now I want some myself...

[Kimstu]

All I did was toss crappy ears atop other stuff to rot compost-style and Nature did the rest.

The OP asked about human intervention, and for the third year in a row, corn has popped up without me doing a thing for it. I would call that pretty reliable.

Well, it sounds from your description as though you at least pulled enough shuck off the ear to determine that the seeds were "crappy", and then tossed the ear (with exposed seeds) into a nutrient-rich environment. I think that counts as at least some human intervention.

The question is, if you tossed one of those crappy ears away in an abandoned field, would you have a patch of wild corn there a few years later? Prolly not.

[Colibri]

But I stand firm that it does *not* require humans to grow/spread on its own.

....

I have also seen plenty of stray corn growing along canals in south/central Idaho (11+ years ago) that in no way could've gotten there by humans unless some person went waaaay way outta their way to plant it (?). Rarely were many stalks present as the cold weather prevented it from getting thick - I presume that killed most seed keeping it from flourishing, and lots of corn was grown commercially along those canals to provide seed to spread by whatever means.


I think the main point is that, while corn may sometimes germinate on its own, it has serious dispersal limitations. It is not going to spread out of the general area where it is being grown agriculturally; and it will not persist for very long (more than a few seasons) in areas where it is not being planted and cultivated.

[Ionizer]

Well, it sounds from your description as though you at least pulled enough shuck off the ear to determine that the seeds were "crappy", and then tossed the ear (with exposed seeds) into a nutrient-rich environment. I think that counts as at least some human intervention.

The question is, if you tossed one of those crappy ears away in an abandoned field, would you have a patch of wild corn there a few years later? Prolly not.

Nope, no husking/exposure of bad ears - I do not open up trashed ears at all since are generally too small to be of any use to my belly, so why mess with that silk? When the tip of ear is black/rotting or eaten by bugs, its outta there without further adieu. Roots emerge out top of ear or through holes in husks they find, ime. The ones this morning were all emerging from tips, fwiw. If I ever pull back husks, it is to eat whatever is there as I walk back into house. Those go into trash can by back door when I'm done and never seen again :) I am guessing that some corn ssp will live year-to-year better than others (field corn -v- 'improved' sweet corn or other similars) but have no real experience with that. Might be interesting to try it this next year, though. I really am curious about this now. I am going to try and contact someone at Oklahoma State asap to get more info on this as I find a few more hits on Google about corn's invasiveness, and inquiring minds gotta know, ya know....

[neuroman]

and [corn] will not persist for very long (more than a few seasons) in areas where it is not being planted and cultivated.

Sounds like a challenge! Who has a few acres of arable land they don't need to do anything with for the next decade?

[Digital is the new Analog]

I used to have banana trees in my back yard. They would bear fruit once and then keel over and die. Well before they died, there would be one or two babies growing. The only thing I ever did was cut off the bananas, and usually, but not always, remove the dead tree to make room. I'm quite confident that they would have survived if I did nothing to them.

-D/a

[yabob]

I used to have banana trees in my back yard. They would bear fruit once and then keel over and die. Well before they died, there would be one or two babies growing. The only thing I ever did was cut off the bananas, and usually, but not always, remove the dead tree to make room. I'm quite confident that they would have survived if I did nothing to them.

-D/a
It keels over and dies because it isn't really a tree. The banana is actually the world's largest herbaceous flowering plant. Shoots develop from the underground rhizome in your case, which is the same original plant. BTW, you aren't far off calling them "babies". Bananas have "pups".

[SCSimmons]

BTW, you aren't far off calling them "babies". Bananas have "pups".
Hey! You're going to make me feel bad about eating them if you keep this up!

[Digital is the new Analog]

It keels over and dies because it isn't really a tree. The banana is actually the world's largest herbaceous flowering plant. Shoots develop from the underground rhizome in your case, which is the same original plant. BTW, you aren't far off calling them "babies". Bananas have "pups".

I feel a little bit of ignorance falling away..

[Aspidistra]

Yeah, it looks as though we need a clarification of the question in the thread title here. There are plants that literally cannot reproduce themselves without physical intervention by humans, as in the case of the seedless/grafted fruits mentioned above; and then there are plants that can physically reproduce untouched by humans, but not reliably enough to create sustainable populations, as in the case of maize/corn.

It's my daughter's question originally (we were discussing bananas, and how all the bananas we eat are actually clones of each other), and I think "any way that would lead to an interesting discussion" is probably a good clarification of it.

So probably "anything seedless" would be a good contender. But then again, I know strawberries, though they have seeds, don't need them to make another strawberry plant - just send down some suckers. Can, say, seedless grapes do that too?

I had thought of corn, because I knew it had been greatly bred away from the original wild plant, but wasn't sure. (I guess the verdict at the moment is 'still not sure' - depends how you define it)

[Colibri]

So probably "anything seedless" would be a good contender. But then again, I know strawberries, though they have seeds, don't need them to make another strawberry plant - just send down some suckers. Can, say, seedless grapes do that too?

Grapes can propagate themselves by sending up sucker shoots from the roots. Many plants can reproduce asexually by sending out runners or producing sucker shoots. The resulting offspring are clones, genetically identical to the parent plant. So if you include this mode of reproduction, there would be few if any plants that absolutely can't reproduce without the aid of humans.

I had thought of corn, because I knew it had been greatly bred away from the original wild plant, but wasn't sure. (I guess the verdict at the moment is 'still not sure' - depends how you define it)

Corn produces fertile seeds, which can germinate and grow into adult plants on their own. It just doesn't disperse well enough to maintain a viable population in the wild for any length of time.

[Deadpool2k]

All are able to reproduce by themself cus if you analyze once they did it before human learn how to manipulate them

[Kimstu]

All are able to reproduce by themself cus if you analyze once they did it before human learn how to manipulate them

But the point is that nowadays, human beings have "manipulated" some plants with years or centuries of selective breeding to the point where they can't any longer reproduce by themselves.

Just because the wild ancestors of all modern plants were fully self-reliant doesn't mean that all their pampered cultivated descendants today could still make it on their own. They've evolved into a culture of dependency, so to speak.