Daylilies forum: Gossard 2016's

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Name: Ashton & Terry
Jones, OK (Zone 7a)
Windswept Farm & Gardens
Hostas Lilies Hybridizer Keeps Sheep Pollen collector Irises
Hummingbirder Region: United States of America Daylilies Region: Oklahoma Butterflies Celebrating Gardening: 2015
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kidfishing
Dec 3, 2015 11:09 AM CST
http://heavenlygardens.com/index.html
Heavenly New Frontiers... Blinking
Kidfishing
Name: James
South Bend, IN (Zone 5b)
Hostas Enjoys or suffers cold winters Birds Seed Starter Annuals Region: Indiana
Region: United States of America Dog Lover Daylilies Container Gardener Plant and/or Seed Trader
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JWWC
Dec 3, 2015 1:12 PM CST
Yeah ...I've got a few questions about that one. When I have some time I will try to get on the phone with Jamie. He does have a great set of dips this time. I like all of them and love most! Thumbs up
Name: emily
East Tn (Zone 6b)
Daylilies
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Redhorseeg
Dec 3, 2015 3:12 PM CST
I went to Northern Mecca this year and I bought a gorgeous G1 seedling. Boy i didnt know what i was getting!!
Name: emily
East Tn (Zone 6b)
Daylilies
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Redhorseeg
Dec 3, 2015 5:11 PM CST
Here is a Pic of it from this summer in his Garden:

Thumb of 2015-12-03/Redhorseeg/792619

Name: James
South Bend, IN (Zone 5b)
Hostas Enjoys or suffers cold winters Birds Seed Starter Annuals Region: Indiana
Region: United States of America Dog Lover Daylilies Container Gardener Plant and/or Seed Trader
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JWWC
Dec 3, 2015 5:14 PM CST
That's a decent lookin plant for sure.
Name: Betty
Bakersfield, CA
Charter ATP Member I was one of the first 300 contributors to the plant database! Birds The WITWIT Badge Region: United States of America Roses
Irises Cat Lover Daylilies Region: California Garden Ideas: Level 1
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Betja
Dec 3, 2015 7:39 PM CST
That's a beautiful seedling, Emily!

Betty
Name: Rob Laffin
Mariaville, Maine (Zone 4b)
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RobLaffin
Dec 3, 2015 8:31 PM CST
Maurice,
I'd be very interested to hear your thoughts on the work JG is doing on unusual ploidys as set forth here:
http://www.heavenlygardens.com/image-viewer.htm?Heavenly-New...
Rob
Name: Peter
Allentown PA (Zone 6b)
Cat Lover Seed Starter Greenhouse Bee Lover Enjoys or suffers cold winters Pollen collector
Hybridizer Region: Pennsylvania Daylilies Vegetable Grower
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Nysbadmk8
Dec 3, 2015 9:17 PM CST
RobLaffin said:Maurice,
I'd be very interested to hear your thoughts on the work JG is doing on unusual ploidys as set forth here:
http://www.heavenlygardens.com/image-viewer.htm?Heavenly-New...
Rob


If you're on facebook... Maurice commented on a post I started on G1 in the daylily hybridizers nook.
[Last edited by Nysbadmk8 - Dec 3, 2015 10:44 PM (+)]
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Name: Becky
Sebastian, Florida (Zone 10a)
Celebrating Gardening: 2015 Daylilies Hummingbirder Butterflies Seed Starter Container Gardener
Charter ATP Member I was one of the first 300 contributors to the plant database! Garden Ideas: Master Level Lover of wildlife (Black bear badge) Birds Ponds
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beckygardener
Dec 3, 2015 11:09 PM CST
That is very interesting about the ploidy of some of the hybrids! Fascinating and may have some valuable daylily children in the future.
What lies behind us and what lies before us are tiny matters, compared to what lies within us.
Garden Rooms and Becky's Budget Garden
Name: Mayo
The Netherlands, Europe (Zone 9a)
Region: Europe Cat Lover Daylilies Irises Dog Lover Hellebores
Rabbit Keeper Container Gardener Organic Gardener
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Mayo62
Dec 4, 2015 5:43 AM CST
I Lovey dubby most of them!
Good thing I can import them Big Grin


Mayo
a DL flower a day keeps the doctor away
Name: Maurice
Grey County, Ontario (Zone 4b)
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admmad
Dec 4, 2015 10:29 AM CST
[quote="RobLaffin"]I'd be very interested to hear your thoughts on the work JG is doing on unusual ploidys as set forth here:
]http://www.heavenlygardens.com/image-viewer.htm?Heavenly-New...

Jamie is using a flow cytometer to measure the amount of DNA in cells from various daylily plants. From those estimates he calculates the ploidy of the plant.

Flow cytometry (FCM) is a scientific method and so I would examine his methods, protocols, analyses, conclusions using scientific standards. He has not provided the details of those or indeed enough details.

The characteristics described for Heavenly New Frontiers, described as a pentaploid, are unusual for a pentaploid. Pentaploids, like triploids, have unbalanced chromosome counts and will have abnormal chromosome alignment. They are usually infertile. They are not always completely sterile and some may have some fertility, for example as Arisumi found with the triploid daylily 'Garnet Robe'. However, it would be very unusual for a pentaploid to be as fertile as Heavenly New Frontiers (described as extremely pod and pollen fertile).

Using a flow cytometer to determine the amount of DNA is an accepted technique. However, there are many possible problems that make the next step of determining the ploidy difficult and many precautions that one should take. I will quote several passages from a book on flow cytometry. FCM is the abbreviation for flow cytometry.

"FCM has many advantages over other methods; however, these benefits are realized only with awareness of potential pitfalls and technical guidelines specific to measuring ploidy."

"It must be emphasized that conventional chromosome counting should follow any suspicion of chromosomal heterogeneity inferred from FCM data in
order to elucidate its nature. "

"A fundamental assumption in using FCM to assign ploidy is that increments of DNA content correspond in a predictable way to increments in chromosome
number. Errors in interpretation can occur when this assumption fails..."

"Moreover, errors (ploidy underestimation or overestimation) may sometimes be introduced even when comparing different cytotypes of the same species, unless FCM measures are combined with chromosome counts"

"To ensure that these advantages of FCM are realized in a consistent way, efforts have been made in recent years to promote universal guidelines for the measurement of nuclear DNA content in plants (Bennett et al. 2000a; Dolezˇel and Bartosˇ 2005). These include: (i) the use of histograms obtained after the analysis of >5000 nuclei and with DNA peaks with coefficients of variation (CVs)<3%, (ii) tissue preparation methods (i.e. chopping) and tissue types (i.e. fresh leaves) that will yield these values, (iii) replication of individuals across three different days, (iv) stains that are not basepair specific (e.g. propidium iodide, PI), and (v) internal plant standards that are as close as possible to the study species in DNA content, without overlap (Dolezˇel and Bartosˇ 2005; Johnston et al. 1999; Marie and Brown 1993; Chapter 4). These recommendations have been driven by the requirements of genome size studies and, at their most basic level, are intended to ensure that such estimates are accurate (i.e. reflect the true DNA content) and precise (i.e. have a variance low enough to allow for the resolution of small differences in absolute DNA content)."
---
This is from a published paper, it requests that the term "ploidy" be used only when chromosomes have been counted and that "DNA ploidy" be used when the amount of DNA has been estimated - basically because DNA ploidy may not provide a correct estimate of the number of chromosomes or ploidy,

"There is an ever-increasing amount of cytogenetic data in plant sciences obtained by cytometric techniques, particularly flow cytometry. However, as these methods determine nuclear DNA amount irrespective of the number of chromosomes, a discrepancy between cytometric and karyological data may occur. To avoid potential bias, we appeal for consistency, distinguishing between the terms "ploidy / aneuploidy" referring to chromosome numbers and "DNA ploidy / DNA aneuploidy" to nuclear DNA content."
---
The daylily ploidy characteristics need to be confirmed with valid observations of chromosome counts.
Maurice
[Last edited by admmad - Dec 4, 2015 11:14 AM (+)]
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Name: Rob Laffin
Mariaville, Maine (Zone 4b)
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RobLaffin
Dec 4, 2015 2:06 PM CST
Thanks very much, Maurice, for taking the time to lay all that out. At least now I have some sense of what is going on. I have to assume that FCM must offer some advantage of traditional chromosome counting - easier or faster?

If one had a plant and was unsure of its ploidy and wanted to know, then a FCM test might indicate ploidy, but the reliability of that determination would be subject to question unless the tester A) followed the specific protocols you quoted above, or B) confirmed through chromosome counting. Is that fair?

If tet conversions have some tendency to throw odd ploidys, that would provide at least one explanation for the fertility problems users of conversions sometimes report. I assume these problems be avoided by waiting for the next generation?

It's all interesting. I appreciate your willingness to share your scientific expertise on these things.

Rob
Name: Maurice
Grey County, Ontario (Zone 4b)
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admmad
Dec 4, 2015 2:54 PM CST
RobLaffin said:Thanks very much, Maurice, for taking the time to lay all that out.

You are quite welcome.
I have to assume that FCM must offer some advantage of traditional chromosome counting - easier or faster?

Yes.

If one had a plant and was unsure of its ploidy and wanted to know, then a FCM test might indicate ploidy, but the reliability of that determination would be subject to question unless the tester A) followed the specific protocols you quoted above, or B) confirmed through chromosome counting. Is that fair?

Even if the tester followed all the protocols and was an expert at FCM there would still need to be a chromosome count. FCM is not a field that I am competent in but my understanding is that it is not yet very reliable in detecting differences in small numbers of chromosomes (or small chromosome size differences).

So a tetraploid daylily might have 45 (or 46, or 47, etc.) chromosomes and FCM would be unable to identify it as abnormal. It is also possible for two plants to have the same amount of DNA but different numbers of chromosomes or have the same number of chromosomes but substantially different amounts of DNA.

If tet conversions have some tendency to throw odd ploidys, that would provide at least one explanation for the fertility problems users of conversions sometimes report. I assume these problems be avoided by waiting for the next generation?


Daylilies are naturally diploid and so the mechanisms for producing gametes, pollen and egg are able to divide the chromosomes evenly into the gametes successfully at a very high percentage of the time. Then tetraploids were created. With four chromosomes the methods that work well with a pair become less effective. A pair of chromosomes can align with each other end to end and can be evenly divided into two new equally balanced daughter sets [diploids have 11 pairs of chromosomes, each pair is different, each gamete must get one copy of each pair to total 11 chromosomes so that when the two gametes join the embryo once again has 11 pairs or 22 chromosomes].

When chromosomes align (or try to align) in tetraploids there can be a mess. They may align as a quadruplet. They may align as a triplet and a single. They may align as two pairs. There are eleven sets that have to align. Each set can align in a different way. If all 11 sets aligned as two pairs then tetraploids would be equally as fertile as diploids (more or less) and there would be no problems as long as they always aligned in that pattern. But they don't and there is nothing to make them do so in new tetraploids. So what happens is that there are gametes that should have had 22 chromosomes that have 21 or 23 or 20 or 24, etc. The further from a balanced count of 22 the less viable the gamete. The more gametes with non-22 counts the less fertile the daylily.

New conversions would have the most fertility problems because of the above (but also because many are not complete tetraploids and may have large amounts of diploid tissue still where it counts in the cells that make gametes).

With the passage of generations, as long as hybridizers select for better fertility, the number of tetraploid daylilies that form gametes with perfect sets of 22 in high proportions (and those proportions) will increase (although it may take the millions of generations that natural tetraploid species have had for fertility to be approximately normal).
Maurice
[Last edited by admmad - Dec 4, 2015 3:10 PM (+)]
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Name: Rob Laffin
Mariaville, Maine (Zone 4b)
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RobLaffin
Dec 4, 2015 5:58 PM CST
Maurice,
Once again, thank you very much for setting all that forth so clearly. I have very little science background, but after Googling a number of the terms you used, and reading your post several times, I think I get at least the big points.

So FCM, by measuring DNA, which bears some, but not a perfect/constant, relationship to chromosome count, offers a reasonable guess of chromosome count, and this is of some value because FCM is easier and faster than the most accurate method, which is counting chromosomes.
The trade-off is ease for accuracy.

When you say:
"If all 11 sets aligned as two pairs then tetraploids would be equally as fertile as diploids (more or less) and there would be no problems as long as they always aligned in that pattern. But they don't and there is nothing to make them do so in new tetraploids"

does that mean there is something that would make them align properly in OLD tetraploids? And if so, would that just be from careful selection of the most fertile conversions, or is there some tendency for them to 'learn' to align better over time (successive generations)?

Rob
Name: Maurice
Grey County, Ontario (Zone 4b)
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admmad
Dec 4, 2015 8:37 PM CST
RobLaffin said:So FCM, by measuring DNA, which bears some, but not a perfect/constant, relationship to chromosome count, offers a reasonable guess of chromosome count, and this is of some value because FCM is easier and faster than the most accurate method, which is counting chromosomes.
The trade-off is ease for accuracy.

Yes, one way to look at it is that when a researcher wants to get an overall idea of what might be the situation in a large group of individuals of one species or of many related species FCM provides that. Then far fewer more intensive chromosome counts can be made on similar groups (similar in more ways than the amount of DNA they have). It helps group similar individuals into groups, such as species (in terms of evolution). It is just one measure that helps classify individuals into similar or related groups.
FCM is also a characteristic by itself.
As well, once a species or group of species has been examined from both FCM and chromosome viewpoints and the two related (and it has been found that there are no known reasons in that grouping that causes the relationship between the amount of DNA and the number of chromosomes to fail) then FCM can be used by itself in other studies of those species or groups of species.

When you say:
"If all 11 sets aligned as two pairs then tetraploids would be equally as fertile as diploids (more or less) and there would be no problems as long as they always aligned in that pattern. But they don't and there is nothing to make them do so in new tetraploids"

does that mean there is something that would make them align properly in OLD tetraploids?

Yes, as long as by OLD one means the number of generations since the tetraploid conversion.

And if so, would that just be from careful selection of the most fertile conversions, or is there some tendency for them to 'learn' to align better over time (successive generations)?

It could partly happen because of deliberate planned selection of the most fertile conversions but it would happen even without that.
The tetraploids that are more fertile (whether new conversions or not) would be expected to produce more (say) pollen with the proper set of chromosomes (22). At least some of them would do that because they were genetically different from the other tetraploids that produced less properly balanced pollen. Because they have more good pollen and because they are more fertile they will on average produce more seedlings and contribute more seedlings to the next generation. So the genes that help tetraploids achieve higher fertility by producing fewer unbalanced pollen (for example) increase and those genes that do not, decrease (slowly). Of course, if hybridizers deliberately introduce tetraploid daylilies with low fertility (for example, introducing a plant that was the only seed in a pod when many pollinations were required to even get that one seed) then they would be acting against that selective force and the fertility (and chromosome aligning) would not necessarily become better with each passing generation. And each time a new diploid is converted to a tetraploid the process moves backward somewhat.
Maurice
[Last edited by admmad - Dec 4, 2015 9:02 PM (+)]
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Name: Rob Laffin
Mariaville, Maine (Zone 4b)
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RobLaffin
Dec 4, 2015 10:11 PM CST
Thanks once again, Maurice. It's so helpful the way you answer the questions. I suspect if one (a layperson, me for instance) tried to learn this cold from a book, they would soon be overwhelmed with technical words and concepts. The way you are explaining it, I can understand it.

So let me ask you this - if someone were to do a careful study of [some sufficiently large number of] hybridized, tet daylilies using both FCM and chromosome counts and found there was no indication that the relationship between DNA measurement and chromosome count would fail, can they from that point forward reasonably rely on FCM alone? Or, does this not work because tets are not a species unto themselves, but are conversions derived from a number of different species? Is there any reason to think a tet intro that traces its lineage back to H. Altissima (e.g.) would have the same relationship between DNA measurement and chromosome count as a tet intro that traces back to H. Sempervirens? Or does the fact that modern tet intros trace their lines back to a number of different original species mean they cannot be relied upon to all behave in a substantially similar way re: reliability of relationship b/w FCM and chromosome count?

Last (and final!) question: When a tet is discovered to be pollen fertile but pod sterile (or vice versa) does that mean that the pollen gametes have the normal complement of 22 chromosomes, but the egg gametes are likely to have fewer, or more than 22? Is that a likely reason for the pod infertility? If so, what would be the best way to 'fix' that through hybridizing? Look for a sib that is pod fertile and breed to that, trying to pick up pod fertility while keeping the genes limited to this particular cross? Or just breed to some other, unrelated tet known to be pod fertile and go with the most fertile kids? It's curious, because large-flowered UFs are often very difficult as pod parents, and I am wondering what it might be, genetically, that might help explain that and point the way to correcting it. Also, there are some large-flowered UFs that are Pod Very Difficult, but sometimes success can be had by making crosses in cooler weather. Would this mean there might be wrong # of chromosomes in the eggs, but this is somehow ameliorated by cooler weather? Could that be? Or is it more likely that you just lucked out and got a flower where the eggs did have the correct # of chromosomes?

I promise that's my last question. You're being very generous with your time and knowledge, and this is very interesting and helpful.

Rob
Name: Maurice
Grey County, Ontario (Zone 4b)
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admmad
Jan 1, 2016 5:56 PM CST
@RobLaffin Did I answer your last two questions from your last post somewhere else? Otherwise I seem somehow to have missed them, if so I am sorry and if you let me know I will post answers here. I am posting answers here.

if someone were to do a careful study of [some sufficiently large number of] hybridized, tet daylilies using both FCM and chromosome counts and found there was no indication that the relationship between DNA measurement and chromosome count would fail, can they from that point forward reasonably rely on FCM alone?


Assuming that the methods used to do the FCM accounted for all the possible known problems associated with using FCM for ploidy conclusions and that those same methods were used in future FCM studies then yes from that point forward one could reasonably rely on FCM alone. That does not mean that the FCM analyses might not fail in the future for some unknown new reason but those should be rare. However, I would add that it would always be wise/prudent to confirm any very unusual biologically unorthodox ploidy findings based on FCM with chromosome counts. The ploidy results based on FCM being suggested recently for daylilies are extremely biologically unorthodox.

Such a study would have to find that the maximum amount of DNA in any diploid never ranged up to a value that overlapped with the lowest amount of DNA in triploids; that the maximum amount of DNA in any triploid never ranged up to a value that overlapped with the minimum amount of DNA in any tetraploid and so on. Such studies would need to be done on substantial numbers of diploids triploids and tetraploids. That would currently be very difficult as there would not be enough known verified triploids. The daylilies chosen to be studied would have to be a random sample of all possible daylily genotypes. That would mean that registered cultivars would not be a good choice as they are a selected sample. The size of the random samples would probably need to be quite large but that depends on the shape of the DNA amount distribution. Below are just three examples of possible distributions. The important parts are the tails of the distributions.

Thumb of 2016-01-02/admmad/8a0844

Is there any reason to think a tet intro that traces its lineage back to H. Altissima (e.g.) would have the same relationship between DNA measurement and chromosome count as a tet intro that traces back to H. Sempervirens?


No there is not. Different species in the same genus (Hemerocallis) with the same chromosome number can have different amounts of DNA.

Or does the fact that modern tet intros trace their lines back to a number of different original species mean they cannot be relied upon to all behave in a substantially similar way re: reliability of relationship b/w FCM and chromosome count?


Yes. Different daylily cultivars, both tet and dip, cannot be relied upon to have the same amount of DNA even when the chromosome counts are the same.

When a tet is discovered to be pollen fertile but pod sterile (or vice versa) does that mean that the pollen gametes have the normal complement of 22 chromosomes, but the egg gametes are likely to have fewer, or more than 22?


No.
It would usually mean that the cultivar had a genetic variant that affected female fertility but not male fertility (female sterile). There are also genetic variants that affect male fertility but not female fertility (male sterile) and probably genetic variants that affect both male and female fertility.

Is that a likely reason for the pod infertility?


It is a possible reason but with our current level of knowledge about daylilies not the most likely reason.

If so, what would be the best way to 'fix' that through hybridizing? Look for a sib that is pod fertile and breed to that, trying to pick up pod fertility while keeping the genes limited to this particular cross? Or just breed to some other, unrelated tet known to be pod fertile and go with the most fertile kids?


True pod fertility is probably quite difficult to show in daylilies because daylilies have an incompatability system that prevents self-pollinations from working. This is not present in all daylily cultivars, but probably is present in the majority. The system has not been studied well but Stout did make some preliminary observations. Basically (with many assumptions and generalizations) the pod parent will carry certain female identifiers and certain male identifiers and the pollen parent will carry certain female identifiers and certain male identifiers. In a cross where the female and male identifiers are the same the cross will fail to produce viable seed. That means that a cross of cultivar A x cultivar B may suggest that cultivar A is pod sterile (because it is known that cultivar B is male fertile from other crosses) but in fact the cross of cultivar A x cultivar C succeeds indicating that cultivar A is not pod sterile. Actually the cross of cultivar B x cultivar A may succeed. That is because in the cross of A x B it is the A female identifiers that are combined with the male B identifiers but in the cross of B x A it is the B female identifiers that are combined with the A male identifiers.

It's curious, because large-flowered UFs are often very difficult as pod parents, and I am wondering what it might be, genetically, that might help explain that and point the way to correcting it. Also, there are some large-flowered UFs that are Pod Very Difficult, but sometimes success can be had by making crosses in cooler weather. Would this mean there might be wrong # of chromosomes in the eggs, but this is somehow ameliorated by cooler weather? Could that be? Or is it more likely that you just lucked out and got a flower where the eggs did have the correct # of chromosomes?


Older, larger flowered UFs may be difficult as pod parents because they may be fewer generations removed from crosses with the original triploid daylilies. If that is the case the lower fertility may be due to unbalanced chromosome numbers (complements).That has been speculation in the past but as far as I know there has never been a check of the ploidy of pod-sterile large flower UFs. Another speculation has been that the pistils are too long for the pollen tubes to successfully grow down in time. I strongly doubt that the length of the pistil of any daylily cultivar is too long and affects fertility. On the other hand, high temperatures are known to affect fertility as is high humidity. Both reduce ferility in most plant species and that would include daylilies.


Maurice
[Last edited by admmad - Jan 2, 2016 12:56 PM (+)]
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Name: Rob Laffin
Mariaville, Maine (Zone 4b)
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RobLaffin
Jan 2, 2016 1:33 PM CST
Thanks very much, Maurice. No, you hadn't answered previously, but I figured I had just worn out my welcome with so many questions. I was therefore happily surprised to see your thoughtful and detailed response. I think I understand all you've said, although my nonscientific brain may take a while to fully digest it all.

So, when you say (I have yet to figure out how to make the block quotes everyone else uses):

"That means that a cross of cultivar A x cultivar B may suggest that cultivar A is pod sterile (because it is known that cultivar B is male fertile from other crosses) but in fact the cross of cultivar A x cultivar C succeeds indicating that cultivar A is not pod sterile. Actually the cross of cultivar B x cultivar A may succeed. That is because in the cross of A x B it is the A female identifiers that are combined with the male B identifiers but in the cross of B x A it is the B female identifiers that are combined with the A male identifiers."

what that means is, in the original cross of cultivar A x cultivar B, when that fails, it does not necessarily mean cultivar A is pod infertile; it could just as well mean that the female identifier of cultivar A and the male identifier of cultivar B are so similar [identical?] that cultivar A's incompatibility system rejected the cross. But cultivar B x cultivar A might work because then it's cultivar B's female identifier checking against cultivar A's male identifier and those are not necessarily a match even though A's female and B's male were, so the cross is allowed?

I have tried setting pods on certain large flowered UFs and had little luck, but when I reversed the cross it worked - but usually this was in situations where the second flower was neither larger flowered nor a UF, and known to be quite pod fertile. But in the scenario you describe, even if it were two large flowered UFs being crossed, doing the cross 'backwards' might work if the apparent pod infertility were actually just an incompatibility issue between identifiers in one direction.

I think I get it. So much to learn! As always, thanks very much for your in depth explanation in a way I can understand.

Rob
Name: Maurice
Grey County, Ontario (Zone 4b)
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admmad
Jan 2, 2016 4:27 PM CST
RobLaffin said:Thanks very much, Maurice. No, you hadn't answered previously, but I figured I had just worn out my welcome with so many questions. I was therefore happily surprised to see your thoughtful and detailed response. I think I understand all you've said, although my nonscientific brain may take a while to fully digest it all.


I apologize for not replying sooner. I don't know why that happened. I may have formulated an answer in a text editor and then been called away from the computer before posting it. When I returned I may have assumed it was posted and not checked. I don't know or remember but no, you had not worn out your welcome.

So, when you say (I have yet to figure out how to make the block quotes everyone else uses):

I think you may want to try placing [ and the word quote and then ] at the start of the quote and then [/ and the word quote and then ] at the end of the quote.

admmad said:That means that a cross of cultivar A x cultivar B may suggest that cultivar A is pod sterile (because it is known that cultivar B is male fertile from other crosses) but in fact the cross of cultivar A x cultivar C succeeds indicating that cultivar A is not pod sterile. Actually the cross of cultivar B x cultivar A may succeed. That is because in the cross of A x B it is the A female identifiers that are combined with the male B identifiers but in the cross of B x A it is the B female identifiers that are combined with the A male identifiers.


roblaffin said:what that means is, in the original cross of cultivar A x cultivar B, when that fails, it does not necessarily mean cultivar A is pod infertile; it could just as well mean that the female identifier of cultivar A and the male identifier of cultivar B are so similar [identical?] that cultivar A's incompatibility system rejected the cross. But cultivar B x cultivar A might work because then it's cultivar B's female identifier checking against cultivar A's male identifier and those are not necessarily a match even though A's female and B's male were, so the cross is allowed?


Yes that is correct. It is not known whether the male and female identifiers in daylilies need to be identical for the cross to fail.

But in the scenario you describe, even if it were two large flowered UFs being crossed, doing the cross 'backwards' might work if the apparent pod infertility were actually just an incompatibility issue between identifiers in one direction.


Yes that is correct.

As always, thanks very much for your in depth explanation in a way I can understand.


You are welcome.

Maurice

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