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Stabilizing Mad Hatter F1

F

FloridaChiles

There is a baccatum variety named Mad Hatter F1 that was a 2017 AAS winner. The fruit has a bishop's crown shape and is said to be mild in heat, perhaps even bordering on sweet. There are also reports that it is pest resistant and highly productive. I haven't grown it yet, but I look forward to adding it to my list in the spring.

Since this is an F1, my question is whether anyone has tried to stabilize it. If not, that seems like an interesting project, and I know there are people on this forum with a lot more experience than me, so do you have any advice for such an effort? In particular, how many plants would one want to grow at each generation (after the initial) in order to have a good chance of stabilizing it?
 
The easiest answer is you can't stabilize it.  There's a lot behind the reason why, but a simple answer is certain of the plant's features are a function of heterozygosity.  If you want to stabilize a few features of the plant, color and shape of pods, perhaps, that's probably doable.  Then it's a matter of the number of genetic loci that support your desired traits, which is the whole "punnett square" analysis.  This and how many generations relates to whether your stabilizing for dominant or recessive pairings of traits, but, generally, if you are stabilizing for recessive pairings you need to grow a greater number to see examples of your desired attributes and if you're selecting for any dominant trait not shared by P1 and P2, which you won't know in this case, you'll need to grow through F8  +/- to get the odds in your favor.  If you aren't familiar with the genetics, just grow a bunch of F2's, see if you like any of the results, then keep selecting for similar looking plants for about 8 generations.  It's not a perfect solution, but it's probably the best you can do without quite a bit of research and/or growing large numbers of plants. 
 
You'll definitely lose "hybrid vigor" and practically, you won't be able to select for attributes like pest or disease resistance - which are typically key attributes of the F1's - because you can't "see" those to select for them and you won't have access to a lab and cultured pathogens to test for them.  What you see in the stabilized "hobby-hybrids" is generally stabilization of at most a handful of visual attributes (other than those shared by P1 and P2), but a lack of genetic diversity because the plants have been grown in very low quantity which functionally selects that out.  The F1 hybrids that remain F1's are commercially viable hybrids, which, whether F1's or stabilized, are simply a different animal from hobby-hybrids.
 
Yes their mild and sweet with lots of pods on the Bush :)
 
RpZlvFv.jpg
 
CaneDog said:
The easiest answer is you can't stabilize it.  There's a lot behind the reason why, but a simple answer is certain of the plant's features are a function of heterozygosity.  If you want to stabilize a few features of the plant, color and shape of pods, perhaps, that's probably doable.  Then it's a matter of the number of genetic loci that support your desired traits, which is the whole "punnett square" analysis.  This and how many generations relates to whether your stabilizing for dominant or recessive pairings of traits, but, generally, if you are stabilizing for recessive pairings you need to grow a greater number to see examples of your desired attributes and if you're selecting for any dominant trait not shared by P1 and P2, which you won't know in this case, you'll need to grow through F8  +/- to get the odds in your favor.  If you aren't familiar with the genetics, just grow a bunch of F2's, see if you like any of the results, then keep selecting for similar looking plants for about 8 generations.  It's not a perfect solution, but it's probably the best you can do without quite a bit of research and/or growing large numbers of plants. 
 
You'll definitely lose "hybrid vigor" and practically, you won't be able to select for attributes like pest or disease resistance - which are typically key attributes of the F1's - because you can't "see" those to select for them and you won't have access to a lab and cultured pathogens to test for them.  What you see in the stabilized "hobby-hybrids" is generally stabilization of at most a handful of visual attributes (other than those shared by P1 and P2), but a lack of genetic diversity because the plants have been grown in very low quantity which functionally selects that out.  The F1 hybrids that remain F1's are commercially viable hybrids, which, whether F1's or stabilized, are simply a different animal from hobby-hybrids.
Click to expand...
 
 
Most of the time I find your responses helpful CD --- Until we get too deep, i.e." genetic loci "= the position of a gene or mutation on a chromosome. is way over my head. But please don't stop posting as I do learn from your help.
 
FloridaChiles said:
There is a baccatum variety named Mad Hatter F1 that was a 2017 AAS winner. The fruit has a bishop's crown shape and is said to be mild in heat, perhaps even bordering on sweet. There are also reports that it is pest resistant and highly productive. I haven't grown it yet, but I look forward to adding it to my list in the spring.
 
Since this is an F1, my question is whether anyone has tried to stabilize it. If not, that seems like an interesting project, and I know there are people on this forum with a lot more experience than me, so do you have any advice for such an effort? In particular, how many plants would one want to grow at each generation (after the initial) in order to have a good chance of stabilizing it?
Click to expand...
I've tasted the sweet Mad Hatter.... is there a hot variety?
 
CaneDog, thanks for such a thoughtful response. Obviously I asked in the right place. I realize a lot of the productivity may be coming from hybrid vigor, which obviously a stabilized version of the plant wouldn't possess (although I think I've read in the past that self-pollinating plants don't experience as much hybrid vigor as plants like corn?). And yes, I can see how it would be difficult to maintain the pest resistance, although my garden does have the advantage of exposing my plants to plenty of stressors, a lazy waterer chief among them.
 
I was really thinking about just stabilizing the pod shape, color, and taste, and it seems like you are saying this is precisely what's possible? Obviously, I don't know the parents, and I don't have a DNA sequencer at home, so I am more asking for an order-of-magnitude approximation from people like you who have thought about things like this. In order to try to stabilize those traits, would you think I would need to grow out 10, 100, or 1000 F2 plants? In F3-F8, will those numbers go down? If so by how much?
 
There were some aspects of your second paragraph that I didn't really understand, and I'm wondering if there is something big that I am missing and if you would mind explaining them a bit further. You mention that hobby-hybrids have a lack of genetic diversity. I am assuming (but may very well be wrong) that by "hobby-hybrid", you mean the sort of stabilizing of a hybrid that I am describing, where two plants are crossed and then the favorite F2s are stabilized, not an actual hybrid. If I am not reading that term correctly, please correct me. But then I get to the genetic diversity part and I am more confused. It seems to me that although the Mad Hatter F1 (just to pick the example of this thread) has a lot of heterozygosity (and hence hybrid vigor), its parents were surely homozygous, and so every Mad Hatter F1 is genetically identical to every other Mad Hatter F1? (And boy do dragonsfire's pictures make me want one next year.)
 
FloridaChiles said:
 
CaneDog, thanks for such a thoughtful response. Obviously I asked in the right place. I realize a lot of the productivity may be coming from hybrid vigor, which obviously a stabilized version of the plant wouldn't possess (although I think I've read in the past that self-pollinating plants don't experience as much hybrid vigor as plants like corn?). And yes, I can see how it would be difficult to maintain the pest resistance, although my garden does have the advantage of exposing my plants to plenty of stressors, a lazy waterer chief among them.
 
I was really thinking about just stabilizing the pod shape, color, and taste, and it seems like you are saying this is precisely what's possible? Obviously, I don't know the parents, and I don't have a DNA sequencer at home, so I am more asking for an order-of-magnitude approximation from people like you who have thought about things like this. In order to try to stabilize those traits, would you think I would need to grow out 10, 100, or 1000 F2 plants? In F3-F8, will those numbers go down? If so by how much?  
 
There were some aspects of your second paragraph that I didn't really understand, and I'm wondering if there is something big that I am missing and if you would mind explaining them a bit further. You mention that hobby-hybrids have a lack of genetic diversity. I am assuming (but may very well be wrong) that by "hobby-hybrid", you mean the sort of stabilizing of a hybrid that I am describing, where two plants are crossed and then the favorite F2s are stabilized, not an actual hybrid. If I am not reading that term correctly, please correct me. But then I get to the genetic diversity part and I am more confused. It seems to me that although the Mad Hatter F1 (just to pick the example of this thread) has a lot of heterozygosity (and hence hybrid vigor), its parents were surely homozygous, and so every Mad Hatter F1 is genetically identical to every other Mad Hatter F1? (And boy do dragonsfire's pictures make me want one next year.)
Click to expand...
 
Yeah, I know how that is.  Seems about every time I visit Dragonsfire's glog I end up wanting to grow something new.  :)
 
Technically you need grow only one of the F1 seeds, because P1 and P2 will be homogenous for the traits that are fundamental to the variety.  F1 hybrids come from very stable parents, so while the results aren't exact, they're consistent.  Nonetheless, I'll typically grow at least 2 F1's just to be safe against any issues or accident with one of them. If you can get F2 (isolated) seeds from someone who's already grown the F1, you'll save yourself a needless growing generation because you don't - or at least rarely would - have to select among F1's from stable parents.  Note that this definitely does not apply when you see people make crosses like P1 Stable x P2 F3 generation.  These can produce all sorts of different results at F1.
 
F2 is when you want to grow the most plants. The reason is that while the F1 seeds contained a P1 allele and a P2 allele at every spot (locus) along the chromosomes, everything gets mixed up at F2.  Some will have P1/P1, some P2/P2 and some will have P1/P2.  You have to be able to see the all the characteristics you want in one of your F2 plants so when you select that plant you know it has the genes you want to carry forward to the final stable pepper. If you select one that's P1/P1 and you want P2/P2, you'll never get it because that P2 is gone forever.  So, if one of your F2 plants doesn't have the traits you want, you'll need to plant the F2 seeds again until you see an F2 that has what you want and then take that one forward - note that this isn't always technically true, e.g., unpaired recessive genes are hidden but you might know that they're there by understanding the genetics, but that's a big tangent at this point.
 
A rule of thumb for how many F2 to grow is grow more plants the more different traits you're selecting for.  Also, grow more if you're crossing a light colored pepper with a dark pepper and hoping the cross has the lighter color.  For what you're doing, I'd try to grow at least 6.  Growing more than perhaps 10 is probably getting into diminishing returns for the use of space.  Again, this is for a mad hatter F2, there are crosses that can require LOTS of F2's to have any chance of the desired outcome - getting plants that produce white pods is a good example of this.
 
Once you have your F2 plant that looks/tastes like you want, you likely don't need to grow large numbers of plants each generation.  Knowing the genetics still helps here, but 4-6 is probably enough.  In future generations, if you're getting a lot that look like they're supposed to, you probably don't need to grow as many.  If you're getting fewer good results, or you get none and have to repeat a generation, increase your numbers.
 
As to hobby hybrids, every cross I've ever made has been a hobby hybrid.  You can consider that for every gene pair that creates a trait you can see or taste, there are lots of others that affect the plant in ways we can’t see or easily detect.  You can't select for these traits, but if you grow out seeds from only one plant you're unknowingly selecting for them by limiting yourself to only the genes in that one plant.  If you grow out two plants, you're going forward with more possible combinations of these hidden genes.  The more plants you grow and take forward, the fewer hidden genes you're losing each generation.  Commercially viable hybrids typically grow forward with a minimum of 50 plants each generation, usually more, so the hidden genes aren't disappearing based on the selection of only one plant.  As to the commercial F1's parent plants, they have lots of genes pairings that are stable/homogenous, but they still have plenty of hidden ones that aren't. More of these will carry down when more plants are grown out.
 
There's still another big part of this that relates to dominant vs. recessive genes, but I'll leave that alone for now.
 
If you're interested, here are the best resources I know of to get started with pepper genetics.  It's not a lot of reading, but if you read it and understand it you'll have a very strong foundation for understanding pepper crosses.
 
http://kdcomm.net/~tomato/gene/genes.html
 
http://kdcomm.net/~tomato/gene/genes2.html
 
https://the-biologist-is-in.blogspot.com/2015/11/the-color-of-peppers-2.html
 
http://sites.science.oregonstate.edu/genbio/otherresources/punnett%20squares.htm
 
One caveat.  I took plenty of shortcuts and liberties in explaining this so don't take what's said as perfectly true.  It's pretty easy to understand and discuss this stuff 80%, and that's enough for most purposes, but beyond that 80% it starts getting complicated pretty quickly and there are lots of exceptions to the rule and etc.  There's just no way to quickly explain this stuff thoroughly and accurately in any reasonable amount of time.
 
Thank you so much for your elaboration, CaneDog. I did not know about the hidden genes in commercial varieties, although it makes a lot of sense.
 
If anyone who reads this happens to have some seeds from a Mad Hatter F1 they would like to share, please message me and I'll be happy to send you a SASE for them. I'll probably grow out a few of the F1s anyway because I've never seen them, but yes, it would be nice to skip a generation.
 
Nice info Canedog!

The single seed method works well enough using F2 seeds but instead of random seed selection it is easier to plant an assortment of F2 seeds and grow them out and when you find a plant with the right traits, vigor and growth habits you can take cuttings and then isolate them and use them to self pollinate.

For most traits in divergent line crosses the F2 will have a high amount of homozygous specimens. Hybrids can be made stable and tested in two to three seasons or less if you grow indoors or in greenhouses.


For more closely related crosses there tends to be greater variation in F2 and F1 etc and commercially the solution to ideal performance is to create 2 homozygous lines to create a predictable F1 that has high heterosis but unfortunately is very tricky to stabilize without having a linkage map for the alleles in question. I avoid this issue by using asexual propagation on plants that have issues like the hidden genes Canedog mentions above.

I wish I could use anther culture but I'm not equipped for it, it can make a single cross stable in a single year or less... not including field testing.
 
CaneDog said:
 
Yeah, I know how that is.  Seems about every time I visit Dragonsfire's glog I end up wanting to grow something new.  :)
 
Technically you need grow only one of the F1 seeds, because P1 and P2 will be homogenous for the traits that are fundamental to the variety.  F1 hybrids come from very stable parents, so while the results aren't exact, they're consistent.  Nonetheless, I'll typically grow at least 2 F1's just to be safe against any issues or accident with one of them. If you can get F2 (isolated) seeds from someone who's already grown the F1, you'll save yourself a needless growing generation because you don't - or at least rarely would - have to select among F1's from stable parents.  Note that this definitely does not apply when you see people make crosses like P1 Stable x P2 F3 generation.  These can produce all sorts of different results at F1.
 
F2 is when you want to grow the most plants. The reason is that while the F1 seeds contained a P1 allele and a P2 allele at every spot (locus) along the chromosomes, everything gets mixed up at F2.  Some will have P1/P1, some P2/P2 and some will have P1/P2.  You have to be able to see the all the characteristics you want in one of your F2 plants so when you select that plant you know it has the genes you want to carry forward to the final stable pepper. If you select one that's P1/P1 and you want P2/P2, you'll never get it because that P2 is gone forever.  So, if one of your F2 plants doesn't have the traits you want, you'll need to plant the F2 seeds again until you see an F2 that has what you want and then take that one forward - note that this isn't always technically true, e.g., unpaired recessive genes are hidden but you might know that they're there by understanding the genetics, but that's a big tangent at this point.
 
A rule of thumb for how many F2 to grow is grow more plants the more different traits you're selecting for.  Also, grow more if you're crossing a light colored pepper with a dark pepper and hoping the cross has the lighter color.  For what you're doing, I'd try to grow at least 6.  Growing more than perhaps 10 is probably getting into diminishing returns for the use of space.  Again, this is for a mad hatter F2, there are crosses that can require LOTS of F2's to have any chance of the desired outcome - getting plants that produce white pods is a good example of this.
 
Once you have your F2 plant that looks/tastes like you want, you likely don't need to grow large numbers of plants each generation.  Knowing the genetics still helps here, but 4-6 is probably enough.  In future generations, if you're getting a lot that look like they're supposed to, you probably don't need to grow as many.  If you're getting fewer good results, or you get none and have to repeat a generation, increase your numbers.
 
As to hobby hybrids, every cross I've ever made has been a hobby hybrid.  You can consider that for every gene pair that creates a trait you can see or taste, there are lots of others that affect the plant in ways we can’t see or easily detect.  You can't select for these traits, but if you grow out seeds from only one plant you're unknowingly selecting for them by limiting yourself to only the genes in that one plant.  If you grow out two plants, you're going forward with more possible combinations of these hidden genes.  The more plants you grow and take forward, the fewer hidden genes you're losing each generation.  Commercially viable hybrids typically grow forward with a minimum of 50 plants each generation, usually more, so the hidden genes aren't disappearing based on the selection of only one plant.  As to the commercial F1's parent plants, they have lots of genes pairings that are stable/homogenous, but they still have plenty of hidden ones that aren't. More of these will carry down when more plants are grown out.
 
There's still another big part of this that relates to dominant vs. recessive genes, but I'll leave that alone for now.
 
If you're interested, here are the best resources I know of to get started with pepper genetics.  It's not a lot of reading, but if you read it and understand it you'll have a very strong foundation for understanding pepper crosses.
 
http://kdcomm.net/~tomato/gene/genes.html
 
http://kdcomm.net/~tomato/gene/genes2.html
 
https://the-biologist-is-in.blogspot.com/2015/11/the-color-of-peppers-2.html
 
http://sites.science.oregonstate.edu/genbio/otherresources/punnett%20squares.htm
 
One caveat.  I took plenty of shortcuts and liberties in explaining this so don't take what's said as perfectly true.  It's pretty easy to understand and discuss this stuff 80%, and that's enough for most purposes, but beyond that 80% it starts getting complicated pretty quickly and there are lots of exceptions to the rule and etc.  There's just no way to quickly explain this stuff thoroughly and accurately in any reasonable amount of time.
Click to expand...
CaneDog, you rock! Thanks for all this info. Down the rabbit hole I go!
 
Finally at a point where I can start carrying forward genetics, playing with crosses and all that goodness.
 
CaneDog said:
 
Awesome.  Looking forward to pic's of whatever cool stuff you create.
Click to expand...
 
Nice reply above CD!  Appreciate those links also.  I'll spend some time reading them.
 
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