i understand that you can’t simply plant seeds from an apple (or a pear, cherry, plum, or other temperate-zone fruit) and expect the resulting plant to resemble the one the fruit came from. Modern – and “modern” here extends over centuries of time – fruit-growing methods rely upon one type of rootstock, with the fruiting buds grafted in place (the most common practice, although there are others, equally arcane). You get Red Delicious apples from trees that have roots and trunks from some entirely different type of apple, onto which you graft the buds from your result-of-a-few-thousand-experiences Red Delicious tree.
But why won’t the seeds themselves breed true? They’re definitely the seeds of a Red Delicious apple, whatever the rootstock may have been. So I can understand if the rootstock/trunk itself might not be as hale and reliable as the one used by the nursery that grew my apple. But all the guides and webpages tell me that my fruit itself (when I finally get it after seven+ years of tending my tree) won’t be a nice, tasty red Delicious apple – it’ll be some dwarf and likely bitter-tasting fruit.
This is what I don’t understand – I could understand if my home-grown Red Delicious apple isn’t as big and healthy as a nursery apple. But it still ought to be a Red Delicious apple – it’s got all its genes from the fruit, same as the bud. So why isn’t the fruit the same?
Because it’s a hybrid. It’s got a set of genes from one sort of fruit and a set of genes from another sort of fruit. In forming it’s own seeds, some of those genes will be passed down and others will be discarded. In the case you describe, the large, and sweet genes are likely non-dominant, so less likely to be expressed int he offspring.
Also, care and feeding do matter. A less efficient root system will not feed the fruit as well, resulting in a smaller product.
Perhaps, but that’s neither here nor there. It’s not a Red Delicious because of what pollinated its flower, it’s a Red Delicious because someone cut a branch off another Red Delicious tree and grafted it to hardier rootstock and it grew into a Red Delicious tree that made that apple. It’s a clone, and is still making the same tasting apples it used to when it was a branch and not yet a tree.
Its seeds, however, will have a jumble of genetic possibilities. You might get some large mealy apple bearing trees or some small tart apple bearing trees or some crabapple bearing trees all from one handful of apples picked from the same Red Delicious tree. (Is each seed in one apple the same? I don’t know.)
Why? Why should the genetic material of the seeds be different from that of the apple itself? It doesn’t matter that it’s a clone – a clone is supposed to have the same genetic material as the organism. It doesn’t care what the rootstock is, or what the ancestors of the fruit were – it carries the genetic material of that fruit. If i pollinated it with a matching Red Delicioius apple, I’d think that I’d get a Red Delicious fruit. Certainly that bud will be producing red Delicious apples its entire life. And if the other buds came from the same source, I’d think the same would be true of them.
Or am I wrong here? If so, I’d dearly like to know the truth of the matter.
Red Delicious apple trees are all clones of one apple tree that sprouted somewhere, and someone noticed the quality of the fruit, and decided to graft branches of that tree to the rootstock.
And every apple variety is the same. They are all clones of particular apple trees that had qualities that someone thought was worth preserving.
So your Red Delicious apple tree that you bought down at the nursery isn’t just a descendent of the first Red Delicious apple tree, it is genetically exactly identical. And if you pollenated the flowers of a Red Delicious with the pollen of another apple tree, the resulting seeds would be a new unique apple tree. Remember that the apple itself is entirely created from tissue from the parent tree, a Red Delicious tree will always make Red Delicious apples no matter what apple pollenated it. But the seeds inside that Red Delicious fruit won’t be identical to the parent tree, any more than your kids would be identical to you.
And it turns out that apple quality is highly variable, and it is very unlikely for the offspring of any particular apple variety to be a high quality apple. Almost all of them turn out to be crab apples. Only a very few make good eating apples, and only a few of those make commerically viable apples. And apple trees cannot self-pollenate, and since all Red Delicious apples are clones, that means two Red Delicious apple trees cannot pollenate each other. And even if they could, the resulting offspring wouldn’t be exactly identical to the parents, even though the parents are identical, due to chromosome matching. Lots of plants are capable of self-pollenating, but many aren’t, and selfing is not the same as cloning.
The same thing happens with potatoes, or any plant varieties propagated vegetatively rather than by seed. If you grow a potato plant from a potato, the resulting plant is a clone of the parent plant. If you grow a potato from seed the resulting potato is a random variety, that will have variable qualities and will very likely to be dramatically inferior to the parent. Of course, a very few plants turn out to be superior, and that’s where new varieties come from.
For the same reason that human siblings are seldom identical.
Try it this way:
If I breed a Weimeraner female with a dachsund male 1,000 times, I may luck out and get a dog which resembles a Weimeraner in every way except that it has stubby legs. If I manage to get a male and female like that, and breed them, there is still an endless range of possibilities as to how their puppies may come out. And since it took 1,000 tries to get that, it’s actually less likely that the puppies will have those traits.
If, however, I clone the orginal, I will get a very close copy of that dog over and over again. Likewise, if I feed the clones poorly, I will not get as large, hale, and healthy a copy as if I had fed the clone well.
The seeds inside the apple have genes determined by the pollination. That “passes on” to the next generation when you plant them. The taste and size (the “red deliciousness”) of the apple is based on the tree’s genes.
Do all your brothers and sisters look like you and act like you? Neither do apple seeds. You have two human parents, but their genes mix differently for each offspring, so not all your siblings are CalMeachams. Two Red Delicious parents will mix their genes and come up with decidedly not Red Delicious offspring.
What we call Red Delicious is more specific than a species like human, it’s more akin to an individual person, cloned a gajillion times. Imagine if we could cut off your arm and graft a new you onto someone else’s feet. That new you would still never make another MilliCal, even if he bred with your wife. But his scrotum would be identical to yours. The apple’s the “scrotum”*, the seeds are the kids.
*sorta…more like the non-DNA parts of the ovum that are all genetically identical. But you personally don’t have those, I believe.
Yes! Grafting is cloning, in a way. It’s much the same process as cutting a worm in two. You’ll have two genetically identical worms, once they grow themselves back to whole.
This brings up a different but related question, then. If I breed my two short-legged Weimeraners, I’ll still get a Weimeraner, just maybe not one with short legs*. But the implication is that if I breed a Red Delicious with something else. I get something very far removed from a Red Delicious – it’ll be smaller, everyone says, and taste bad. But breeding two random Weimeraners doesn’t give me, in general, a small Weimeraner that tastes bad.
*It can’t be a one-in-a-thousand chance that I’ll get a short-legged Weimeraner. They didn’t have to breed a thousand pairs of cats to get Munchkins. And, using the incredibly sophisticated genetic training they gave me in school, I’d have thought that I had something like a 1/4 probability of short-legged offspring, assuming it’s a single gene responsible.
After breeding and cross-breeding apples for centuries, botanists developed the fruit we know as “Red Delicious Apples”. If you care to continue breeding, you may cross it with another variety, but it will not be a “Red Delicious”, even if pollinated with another Red Delicious. As has been pointed out, the trees you buy are clones of some tree developed decades, even centuries, ago.
Sexual reproduction is messy, in a genetic sense. It takes the genetic material and scrambles it around. You received a set of genes from each parent, and, while you are most likely still “human”, you are not a clone of either one. Same with the apples. The fruit growing on a Red Delicious tree got its genetic material jumbled in the course of pollination. In nature, this is a good thing—by introducing random variations into the population, some mutation or trait may confer better survivability to its possessor, and pass it on through the generations. Not so good for horticulture. When you get some plant that’s what you want it to be, you want to keep it exactly the same from generation to generation. Hence, grafting and other asexual propagation techniques.
Remember, there are two copies of each gene*, and when the organism reproduces it only sends one copy of each gene to the offspring (with another copy from the other parent). And with all the different genes and the various interactions between different versions of each gene, in some species you can get huge variability between parents and offspring, even if the parents are similar or even genetically identical.
actually, in plants, possibly a lot more that two; plants tend to duplicate their chromosomes far more than animals; I’m not sure how duplicated the apple genome is.
Still trying to properly understand this – I think this statement cannot be correct. If it was, the Red Dlicious apple wouldn’t be a clone – it’d be something else. From what you say, it has to have the same genetic code in order to be a Red Delicious, or else it would be one of those dwarf, miserable fruits.
Yes, but I said exactly like a Weimeraner except for the short legs. You could get a D- snout with a W- head and tail. You could get W-ears and coloring on a long D-body. Every differentiating trait is pretty much up for grabs so there are myriad possibilities. (Although some traits will tend to move around in packages, and dominant traits will be far more commonly expressed.) Your first generation will not breed true at all. It takes several generations of careful cross breeding and back-breeding to produce a healthy, true-breeding line.
When it takes 3-7 years to produce fruit, it would take generations of humans to produce a relaiably true-breeding tree. And just when you get one some rogue bee will show up with crabapple pollen, spoiling a twig or two.
I see your problem—the FRUIT is a PRODUCT OF THE TREE. Red Delicious, in this case. The SEEDS, however, are what you are concerned with, and they are genetically jumbled. The process of pollination causes a mixing of the genetic material which is contained in the seeds. The fruit, which we eat, is manufactured by instructions contained in the genetic material of the Red Delicious tree, cloned from its predecessor.
You’re right. It isn’t the Red Delicious apple that has a new genome, it’s the seeds inside the apple. The apple is genetically part of the parent, just like the uterus is part of a human mother, while be baby is not.
As I understand it, the apple itself is a product of the genetic material of the Red Delicious tree, and so will have the right characteristics. The seeds inside it are a product of the pollination, and so any plant grown from them will not be the same. Am I right?
Edit: DMHO and Lemur866 pre-empted me even as I wrote that
The genetic jumble happened a long time ago. Some lucky gardener got (or found in a field) a tree with big sweet fruit. He cut off some branches and grafted them onto existing root stocks to get more big sweet fruit.
Other gardeners have indeed mixed parent trees to get fujis, galas, etc. But they threw away a lot of nasty baby trees that didn’t work out in the process.
It’s like my eggs inside me. Most of the actual egg - the cytoplasm, the cell membrane, the endoplasmic reticuli, etc., are all the same, because my body made them. Only the nuclei are different, because some of them got some bits from my mom and dad and some other bits. They would taste and look identical to one another, if you could eat them, but the offspring they would create would be very different.
