Selfing to achieve 4N breeders - Page 15 - Orchid Board

FairyInTheFlowers · #**141** 12-03-2012, 03:28 PM

There's nothing wrong with you disliking 4n species, as people will always have different views on a given topic! For some reason, though, you using the term "genetically modified" in reference to orchids was really, really agitating me!

Phew, now that we got that out of the way, I have a theoretical question for you, Rob! Ok, so we know it is easily possible to get 3n's by crossing a 4n (that reduces to 2n) with a 2n (that reduces to 1n). Now, the issue with the infertility of 3n's is because it is difficult for the three pairs of chromosomes to divide themselves evenly in chromosome reduction to form the gametes. However, would it be possible to treat a 4n x 2n in flask to make it 6n? I know that there are some 6n hybrids out there, so I know it is a stable ploidy number. Furthermore, would it be possible to breed a 6n (reduces evenly to 3n) with a 2n (reduces to 1n) to obtain a 4n? Mathematically, this should be possible, but I know that in the real world sometimes things ignore mathematical rules. If this is possible, we could really do a whole lot of interesting breeding in the future. . . I anxiously await your thoughts on this!

GirlGoneWild · #**142** 12-03-2012, 05:10 PM

Quote:

Originally Posted by TheBlazingAugust

There's nothing wrong with you disliking 4n species, as people will always have different views on a given topic! For some reason, though, you using the term "genetically modified" in reference to orchids was really, really agitating me!

Phew, now that we got that out of the way, I have a theoretical question for you, Rob! Ok, so we know it is easily possible to get 3n's by crossing a 4n (that reduces to 2n) with a 2n (that reduces to 1n). Now, the issue with the infertility of 3n's is because it is difficult for the three pairs of chromosomes to divide themselves evenly in chromosome reduction to form the gametes. However, would it be possible to treat a 4n x 2n in flask to make it 6n? I know that there are some 6n hybrids out there, so I know it is a stable ploidy number. Furthermore, would it be possible to breed a 6n (reduces evenly to 3n) with a 2n (reduces to 1n) to obtain a 4n? Mathematically, this should be possible, but I know that in the real world sometimes things ignore mathematical rules. If this is possible, we could really do a whole lot of interesting breeding in the future. . . I anxiously await your thoughts on this!

Sorry, I'm not Rob...

....but I believe I read that 6n plants are not stable. I think things start to get messy when you're dealing with pairing up that many chromosomes.

Somebody correct me if I'm wrong...

FairyInTheFlowers · #**143** 12-03-2012, 05:21 PM

Quote:

Originally Posted by GirlGoneWild

Sorry, I'm not Rob...

....but I believe I read that 6n plants are not stable. I think things start to get messy when you're dealing with pairing up that many chromosomes.

Somebody correct me if I'm wrong...

I know at least one cultivar of the classical white, Phal. Doris, is a hexaploid that was used in breeding, potentially in the way that I described. I'm pretty sure that Robert has this fabled hexaploid Doris, but he'd have to chime in and say for sure. I think there are other hexaploids out there too. I remember reading in an old (1991-ish) Orchids magazine that there was a second or third generation hybrid of Vanda Miss Joaquim that was a hexaploid. I think it is when you approach above 6n that you get issues. I think it might be impossible to get near 7n, and as far as I've heard, colchicine treating 4n crosses has been unsuccessful.

orchidsarefun · #**144** 12-03-2012, 06:06 PM

Quote:

Originally Posted by TheBlazingAugust

There's nothing wrong with you disliking 4n species, as people will always have different views on a given topic! For some reason, though, you using the term "genetically modified" in reference to orchids was really, really agitating me!

I don't think you interpreted my post #140 correctly.

I have a naturally occurring 4N species that I like !

If something walks like a duck, looks like a duck and quacks like a duck, I am going to believe its a duck. I don't care if a scientist tells me its a chicken because it has the genes of a chicken !

The proof that only characteristics are being altered doesn't mitigate the fact that once altered its difficult to put Humpty Dumpty together again. I think that you believe that somehow chemical treatment is a panacea to getting better everything whereas I believe that ultimately there is more of a downside and all those ramifications haven't been figured out.....to species, remember. Can we agree to disagree ? Other than Rob's "blue" ( how many years on that ? ), what other notable orchids do you think have been produced that makes you so keen to experiment ? What about the failures of colchicine ? What are those ? If its so great, why isn't there more literature on it ? What breeders are regularly using it ?

TxRobNLa · #**145** 12-03-2012, 06:17 PM

Quote:

However, would it be possible to treat a 4n x 2n in flask to make it 6n? I know that there are some 6n hybrids out there, so I know it is a stable ploidy number.

Yeah, unfortunately it get's really messy and going above 4n rarely results in anything usable. I didn't think there was a Doris that was higher than 4n, but there could have been. Robert had a good 4n pink Doris for a long time. I do know that there was a cultivar of Cast Iron Monarch that was either hexaploid or pentaploid and it did breed. Apparently it caused a lot of really messy aneuploid crosses back when standard phals were being developed, but ultimately due to fertility issues the aneuploids fell out of use and only the tetraploids remained.

Many really talented hybridizers have tried to come up with ways get around the 3n problem. It's only been the few special case plants that have been a workaround and the cases where the hybridizer has been able to coax out a series of crosses enough times to eventually get back to even ploidy levels.

FairyInTheFlowers · #**146** 12-03-2012, 06:38 PM

Ok, I'm now really getting an idea of why you are against converting tetraploid species. Once they are tetraploid, they aren't going back. I assume the duck/chicken comment is directed at the clarification of the real meaning of genetic modification, and I could argue about the use of your metaphor, but for the sake of peace, I'll not. Also for the sake of peace, think of calling an orchid a GM plant as a highly offensive term for my sake, as it really does irritate me. . .

As for the purpose of me converting species, primaries, and complex hybrids to 4n is solely for breeding reasons. As I've mentioned before, there are many hybrids that are 4n that I would love to cross with a 2n novelty, but since I don't want to deal with anueploidy, the only logical option for me (someone who is focused on breeding alone) is to convert 2n's to 4n. Even if it doesn't drastically cause an increase in vigour or flower size (given a large enough population, you could easily find a seedling or several that's won the 'genetic' lottery and is, in fact, a larger and better looking plant), it will be well worth it because the options I will now have to breed with have increased exponentially. Like one of my previous examples I've used: say I want to make a 2n cross between an amboinensis and a white species or hybrid. If a person was restricted to 2n's, the options would be very limited. However, get a tetraploid amboinensis, and you now have the ability to make a clean cross with almost every available white, pink, or purple, most of which have far superior form and flower count than the available 2n species. In other words, my goal is to bring the two divergent roads of Phalaenopsis breeding together. Honestly, in my opinion, I would be quite happy if we saw a complete end to diploid Phalaenopsis breeding, as it would cut out issues of making triploid hybrids.

TxRobNLa · #**147** 12-03-2012, 06:45 PM

I think in terms of the should we create 4n species issue it is definitely going to be better to agree to disagree here.

Quote:

Other than Rob's "blue" ( how many years on that ? ),

I have a lot converted tetraploids. It's actually faster for me to grow out a converted tetraploid seedling than it is for me to grow out a diploid from the same cross. The only reason I have years in all of this is I have a very extensive decades long breeding program that is planned out with multiple stages of goals I want to accomplish.

Quote:

what other notable orchids do you think have been produced that makes you so keen to experiment ?

Most of your tetraploid Cymbidiums come from colchicine treatment. The more recent warm growing and smaller flowered Cymbidiums that are tetraploids also came from colchicine conversion. As far as I know all of the 4n Phrags were from colchicine treatment. Probably a good 50% or more of the tetraploid Cattleya's were also produced from colchicine treatment. Outside of orchids modern tetraploid daylilies are all produced from colchicine or orzyalin treatment.

Quote:

What about the failures of colchicine ? What are those ? If its so great, why isn't there more literature on it ? What breeders are regularly using it ?

The failures resulted in the myth that colchicine treated orchids were poor growers. The bad failures resulted in dead plants in the lab.

You don't have a lot of breeders using it because most breeders either don't have their own lab or they are afraid of working with the chemical. The process is a bit of a pain in the lab, so there are not many labs that offer it as service. It's too hard to make money on doing the treatments. It's the end result that is of value, not the service of doing it. There are many individuals that actually use it all the time but they keep very quiet about it because they are creating their own stud plants to make a profit off of and it's easier to just not say anything and then later offer plants from the resulting crosses. Historically hybridizers have also been extremely guarded and kept a lot of information to themselves to protect their work.

I actually do not release my colchicine protocol to the general public because I personally won't teach people how to do the treatments unless they have a way to do chromosome counts. It's funny in the context of this larger discussion... Believe it or not I actually do have my own set of ethical guidelines that I follow when it comes to this topic. I've given serious thoughts to the ethics for a long time, I know where I personally stand and stick to that.

Best, Rob