a triploid malus floribunda is still likely going to be smaller then 2.5". The question you need to ask is what exactly you want to do with the fruit? If you want an very early or very late season pollinator there crabs for that. You want an apple that makes great sauce, crabs for jelly, crabs for pickles, bitter-sweet crabs to balance out your cider recipe, there is a crab for that? I ordered a Pitmaston Pine Apple this year, its a very small apple and has a strong pineapple flavor. If I graft it on to Bud9 that might just shrink it down to crabapple sized.
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from what I am have reading I think Geneva Crab is Triploid or Allopolyploids
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Allopolyploid infers a plant composed of the full genomes of two related species that usually have different chromosome numbers. A rutabaga is an allopolyploid of a turnip and a cabbage (we’ll argue details later, see triangle of U) that occurred long ago. The resulting plant contains 38 chromosomes which is the full complement of both parents. This differs from a tetraploid which usually results from chromosome duplication in a single species. Okra is an allopolyploid as another example. I have not seen anything published indicating an allopolyploid in apple other than the chromosome doubling event about 65 mya. Do you have documentation showing an example of an apples that is an allopolyploid? Triangle of U - Wikipedia | Apple Genome (part 2) – James and the Giant Corn
I’m going to also add some information about the reason why a triploid can produce seed but not viable pollen. Meiosis in plants diverges significantly as compared to animals. The short version for pollen is that a pollen grain for most plants contains two duplicate cells each with a single set of chromosomes. When there are three sets of chromosomes, only two sets can pair up to initiate division leaving one set of chromosomes unpaired and therefore unable to duplicate and then split into paired pollen cells. Rare events can cause even a triploid to sometimes produce a small number of viable pollen grains. This is significant for example in potato breeding where triploids can be generated and sometimes be induced to produce just enough pollen to be used in breeding.
For the ovule, the process is dramatically different. I am going on memory with this so please check that it is correct. The primordial female cell initiates a duplication where it doubles the number of chromosomes, then doubles the number of cells, then repeats until there is a cluster of 16 cells in the proto-embryo. Eight of the cells are discarded leaving 8 cells to form the embryo. A single set of chromosomes winds up in the cell that can be fertilized by pollen, two sets wind up in the structure that becomes the endosperm, and 5 cells move into support functions. When the pollen grain moves through the style, it splits in half with one set of chromosomes merging with the single set of chromosomes in the ovule and the other merging with the 2 sets of chromosomes in the proto-endosperm. The result is that most of time the seed contains an embryo with 2 sets of chromosomes and triploid endosperm that has 3 full sets fo chromosomes. The endosperm is discarded when the seed germinates and depletes the stored reserves leaving only the growing plant which is normally disploid. Now ask the question, what happens when the pollen grain is from a tetraploid? The resulting seed has 3 sets of chromosomes in the embryo and 4 sets in the endosperm. Voila, now you have a new triploid apple!
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And I understand Hewes Crab is likely an interspecific result (think that’s the term for cross-species progeny) between un-named domestic apple and whatever native crab predominates in Virginia. In the case of Hewes, it is not triploid, but self-fertile or PSF.
There are some other Etter-bred crabs that are less well-known than Wickson but worth trying, such as Crimson Gold, Vixen, Muscat de Venus, Atalanta’s Gold, and Amberoso. All but Crimson Gold are difficult to find except as benchgrafts from Greenmantle Nursery, as they’re trademarked and require non-propagation agreements.
Some other small-to-crab-sized apples that are also worth trying: Chestnut, Trailman, Kerry Pippin, Margil, Wyken Pippin, Yellow Ingestrie, and the aforementioned Pitmaston Pineapple.
I’m growing all of these as either trees or grafts, but so far only a few are old enough to bear yet. (Actually, Yellow Ingestrie has eluded me thus far, but @derekamills will hopefully be able to remedy that next season.)
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Thanks, I keep those in mind. I was very close to getting a Wickson crab last year from Cummins, but didn’t. Maybe when my trees get bigger, I might try grafting some crabs onto them.
I didn’t know Pitmaston Pineapple was a crab, I thought it was just another apple. I guess it’s a small apple, not technically a crab like you mentioned.
This looks to be the best place to mention my observation from yesterday: Looking over the Rambour Franc tree - a triploid - there are absolutely no blossoms developing on it this year. Last year it bloomed all over, for the very first flowers seen on it, setting at least 300 fruits. It is 9 x 9 feet, on Geneva30. I thinned the fruits to 90 and found hardly any viable seeds in them at maturity. With so few full seeds, I had no concerns about it going biennial.
Wrong.
Looks like I must thin it drastically next year in order to break the biennial cycle. Maybe leave a dozen on?
From what I’ve read here and elsewhere, it appears triploid apple varieties do not pollinate other varieties. However, they can be pollinated and create seed. My question is, will these seeds be viable? I love Ashmead’s Kernel, which is triploid, but would love to experiment with breeding it. My hope is that I can pollinate its flowers with pollen from diploid varieties and get seed that will actually grow.
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I don’t think I’ve seen a viable seed from my Ashmead’s, I look every time I eat them. But the seeds are always malformed and shriveled.
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Even if you do find seeds and can sprout them, seedlings of Ahmead’s Kernel won’t be Ashmead’s Kernel. They may be similar or not. Sexual reproduction creates many possiblities in a species as diverse as apples. Graft Ashmead’s Kernel if you want Ashmead’s Kernel.
John S
PDX OR
JohnS, I know, that’s the point. I’m interested in using Ashmead’s as a parent for breeding a new apple, not growing the same variety. The Ashmead’s I’ve got flowering in my orchard for the first time this year is one I grafted to B.118 three years ago.
Given enough random pollination Ashamed kernel will produce seeds. Some of those seeds will be viable. The resulting trees will have a non standard multiple of chromosomes but that does not nessisarly stop it from being a good apple. Stayman Winesap is an example of one of those types of crossing.
Triploids are pollen sterile however and can’t be the male parent to while anything’s possible its not likely a good use of time trying to cross them.
If your really serious however of getting a Ashmed seedling. you can apply, the mutagen Colchicine to the buds are the appropriate time to induce them to not reduce the ovum from 3x when crossed with a normal 1x pollen will yield 4x seed. Crossing that back with a 2x tree will yield more 3x trees.
You may create a great apple out of the 4x stock. My question is what are you goals. Aside from the fun of chance. A goal would be to introduce something like scab resistance gene while maintaining producing an apple similar to ashmeeds.
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learning more about polyploids is still on my to do list.
so take my comments with some skeptisisem. Since i only “know/read” a little about this subject.
But i thought if you used colochine you’d dubble the chromosome. from 2n to 4n. or like with ashmeads 3n to 6n ?
Most often triploids are pollen sterile. But often can stil reproduce from seed if pollinated by diploid pollen from another non triplpoid variety. Although with lower viability. or harder to form seeds. (might need to pollinate a lot of flowers for a few seeds)
I think the offspring could be both diploid (most likely) or triploid (rarer)
BTW colochine is a potent toxine first read up on safety before trying to work with the stuff. (same goes for any other advise you get from “stangers” on the internet)
But im not aware of any tetraploid apples or triploid apples produced by colochine. Do you know of any? or have a link for me to read up on?
From what i understood, colochine usualy kils 99+% of treated seeds/plants (usualy seeds or cuttings) If you have higher survival, most likely the dose is not high enough to reliably produce triploids. And you would likely need to test the offspring for triploids whith somting like flow cytometry anyway.
I don’t know if treating flower buds whith colochine would have any effect apart from maybe killing the flower buds.
something more relevant to the origional topic.
if you download the paper (from the link, no paywall)
You can see a lot of apples that where geneticaly tested. So you can see if they are diploid or triploid. And also if the researched could verify the parent varieities in their genetic test.
The data starts page 5.
colchicine induces polyploidy by preventing the segregation of chromosomes during meiosis that results into half of the gametes (sex cells).
Two double you would need the pollen and ovum to both be unreduced.
clever scientist work the other way also. They can reduce the genome of wheat by pollenating it with oats. The wheat reject the oat dna and set seed with half the chromosomes.
Anyway don’t use me as a guide on this. I never touched colchicine my self with the exception of picking crocus flowers. Colchicine can be retrieved from crocus sap btw.
colchine is not present in crocus sap. But in cholchicum autumnale. This is a different genus from crocus. The plant however resembles a crocus in looks a bit. But flowers in autum. I had a few of them. they are beatiful. but highly toxic to people children and cats to.