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  • #21
Exactly Dustin, even the same Distributor. When some of the N. lowii turned out to be N. x trusmadiensis, he politely declined our offer to exchange them for replacements.
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  • #22
Hi, all.
My putative Jaq x izumiae has opened it's new pitcher now:

Compare.jpg


Here's my pure izumiae for comparison:

izumeae.jpg


They seem subtly different to me, and based on it's origin Rob told me ' despite the appearance, I can't see much liklihood of it not being a hybrid', so I think there must be a range of forms of the plant out there.
Cheers,
T.
 
  • #23
Hi Tony,

Sorry but I don't see any difference there. Can you elaborate? I have seen dozens of N. izumiae and N. jacquelineae and about 10 different N. jacquelineae x izumiae and in all cases the hybrid was easily identifiable from a very young age and quite clearly different from either species.

Tony
 
  • #24
Hmm... Don't know how this happened, all the hybrids we have came from N. jac seed and none from N. izumiae seed. After we realised that not all our N. jac were true, we started to select hybrids by their diffferent appearance from a young age. I'm realy sure there was no mixup with the seeds here, they were even germinated in different nurseries. Could of course be due to the dodgy UK Distributor you purchased the plant from
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I agree with Tony, that it looks just like N. izumiae to me too and I've never seen a hybrid looking exactly like one of the parents. I know you don't want a replacement but I think you deserve one and so we shall send you a typical N. jacquelineae x izumiae hybrid as a gift later in the year.  Are you going to the EEE by any chance?
 
  • #25
[b said:
Quote[/b] (tonyc @ Mar. 19 2006,3:45)]... They seem subtly different to me, ...
Hi,

judging from your pictures only the leaf apex seems to be totally different. I don't know if this variation can occur in the same species?

Joachim
 
  • #26
Hi Rob:

I know beforehand that you have seen and grown these plants long before i learned to grow them, but would it be possible that a jacquelinae X izumiae combination would yield a plant that looks more than izumiae than Jacquelinae eventhough the majority of the plants from this cross would look more like jacquelinae rather than izumiae. This is based on the laws of probabilities in genetics.

Gus
 
  • #27
Hi Gus, I'm really no expert on this. My understanding is that the characteristics of a hybrid follow a binomial distribution with the highest probability that the offspring will bear roughly even characteristics of both parents. However, there is a possibility that it may look almost exactly like one or other parent but the liklihood of that is very small. I think there is a much higher liklihood of someone here making a mistake although I can't imagine how in this particular case. The N. izumiae and N. jac are in entirely different nursery buildings, it's not just a case of someone accidentally placing a plant on the wrong bench or labeling incorrrectly.

Joachim, there can of course be huge variation in form between plants of the same species. A good example is N. rafflesiana of which there are almost no two identical. However, this seems to apply mainly to lowland species and there is usually much less variation with highland species. I have no field experience with N. izumiae and therefore have little idea opf how much the may vary and whether that variation can include differences in leaf apex. I guess it's possible though.
 
  • #28
When dealing with a first generation primary hybrid, a cross between two species, the odds that one offspring look almost exactly like one parent is nearly if not completely zero. The genetic material in each hybrid offspring is nearly identical with half coming from one parent and half from the other. So all the hybrid plants end up looking very similar with only minor variation from one another. Now this doesn't mean that they can't be more like one parent than the other, but there will be little significant variation among the hybrid population.

For kicks.. take two plants from that first generation and sibling cross them. Then you can get theoretically everything from one species to the other with everything in between ;>

Very simplified layout with a single chromosome pair
N. izumiae AA 100% x N. jacquelineae BB 100% =
first generation AB 100%

first generation AB x first generation AB = mix of:
second generation AA 25%
second generation AB 50%
second generation BB 25%

give it a try with more chromosome pairs and you can see how 2nd generation the combination possibilities become like the Lotto Drawing! The first generation though doesn't change much.
 
  • #29
lol seems to be right! this was taught in i think 9th or 10th grade at my school with puttnum squares, i think thats how you spell it?
 
  • #30
Hi Tony and Rob:

You are absolutely right, very clean mendelian genetics. the exact course of events; however, becomes very obscure when we are dealing with several chromosome pairs, then how can we accurately predict the genotype or the phenotype of a hybrid, considering that the chromosomes predicting the sex on Nepenthes for example are not 50%-50% even on a F1 generations when we should predict a more homogeneous gene distribution
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?

Let's hope there was a mix up with the plants to make matters simpler to everyone
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!
 
  • #31
Hi Gus,

Accurately predicting the genotype on primary hybrids is straight forward. Phenotype is another thing altogether as we are all familiar with some species exhibiting more dominance than another. When dealing with previously unknown primary hybrids there is always room for a surprise as you never know for certain how the genes will express themselves in the F1 generation. It is fairly safe to say though that in F1 primary hybrids the range of phenotype differences in the HYBRID population is minimal. Only when you get to F2 and beyond or start mixing different hybrids do you see a much broader range of phenotypes showing up.

As for the sex determination who knows... Perhaps it is multiple genes? If for example it were 2 genes A and B and in order to be female for example 2 B genes needed to be present. All plants with AA or AB were male. Then the ratio would naturally be about 75% male. On the other hand who can say for certain that the ratio really isn't 50% each? Maybe environmental factors cause more female plants to die in the wild so the ratio is skewed? I could probably come up with another dozen hypothesies too
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Tony
 
  • #32
AH yes punnunt squares....genetics was one of my favorite untis. but tony said that in the F2 generation you have a 25% AA(izumiae) 25% BB(jacquelineae) and a 50% AB(jaq x izumiae). THIS DOES NOT MEAN YOU WILL HAVE A CHANCE OF GETTING PURE JAQS OR IZUMIAES IF YOU BREED TWO OF THE HYBRIDS!!! it means that 25% will look more like a jaq, or 25% will look more like a izumiae or 50% it will have balanced characteristics (i asked this to my biology teacher and that was what he said). oh ya and 25% is just an estimate. for example if you have 100 seeds 25 will most likely not be the jaq or izumae. and anybody PLEASE feel free to go against what i have said. okay im done
smile.gif

alex
 
  • #33
What Rob often does, especially with some of the rarer stuff, is grows a bunch of them from seed, and puts some of the seed into tissue culture. The seed-grown plants, not being divided and divided in vitro, reach maturity earlier. The seed grown plants are the first to be sold and then later the tissue cultured plants are released. Seed-grown material is more highly sought after because each plant is a unique individual, whereas tissue cultured plants share their genes with thousands of other clones.

So whenever you see a reference to different individuals from seed on his pricelist, it means they're from seed and not TC. If you seed 'selection from 42 clones' or something like that, it means they are from tissue culture.

In relation to the jacquelineae x izumiae, my understanding is that the hybrid appeared amongst seed-grown plants. Occasionally a hybrid will appear in TC, but Sods Law mitigates against that. When Rob released a bunch of seed-grown lowii, some of them turned out to be Trusmadiensis. Of course, none of their siblings in TC turned out to be the hybrid, they were all pure lowii.
 
  • #34
Er, I'll put my head over the parapet again
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The differences I thought I could see were the 'hybrid' having a subapical tendril insertion, shorter/fewer hairs at the edges of the leaves, a slightly less angular peristome and generally lighter coloring. All of these could well be within the natural variation of izumiae though, I don't know as I've never read the formal description of the species.
But thanks to all for the imput (and I'll be in touch, Rob
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)
Cheers,
T.
 
  • #35
Hamish,

You're quite correct, that's exactly what we do. Only one thing though, we do seem to get a much higher proportion of hybrids appearing in TC than one would observe in the wild and I don't know why, unless they just don't survive well in natural habitat. The best example of this is with N. bicalcarata.  Out of 24 clones we kept in TC we had a large proportion turn out to be unexpected forms and hybrids, some of which I've never seen in the wild. They were:

N. bicalcarata, typical orange flush - about 6 clones
N. bicalcarata, red flush - very rare in Brunei where the seed was collected from
N. bicalcarata x gracilis - several clones
N. bicalcarata 'red shorthorn' - a red form with stubby fangs - one clone
N. bicalcarata x (gracilis x ampullaria) - several clones
N. bicalcarata x ampullaria - one clone

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  • #36
Rob with the more complex ones such as N. bicalcarata x (gracilis x ampullaria) is this just your best guess as to parentage because of what was growing in the area or what? just curious.
 
  • #37
There's a lot of N. x trichocarpa around there and the appearance of the pitcher is exactly what you would expect from that cross. I had already made up my mind and then showed a plant to Ch'ien lee without comment to see what he said. He immediately made the same ID, so I'm pretty sure. I'l see if I can get a photo, it's a very pretty plant.
 
  • #38
Re: sex determination. It is not really genetic in plants, it is hormonal. Most of the research in this area is what the weed-heads have discovered but male plants can be "switched" to female plants by application of certain chemicals at certain times. Now, yes the hormones are genetically controlled but it is not a predetermined thing in plants, there are not "sex chromosomes" like in animals. Regulation of the genes is environmentally regulated at an early age. A slight stress environment favors males which produce copious amounts of pollen (vs. seed) thereby encouraging the availability of greater genetic variation within the geen pool thereby promoting various genotypes, one of which should hopefully be more likely to survive the stressful environment.
 
  • #39
Very interesting Pyro. Charles Clarke has a section in the Sumatra book dealing with gender in Nepenthes populations. A general conclusion reveals males growing out in exposed, harsh areas. I believe they found 100 percent of rafflesiana growing in open harsh environments were male, whereas females were found growing in more sheltered environments, under shrubs and trees.
 
  • #40
Hi Pyro:

Very interesting information. If we analyze it, it'd be very curious to find out why under the same growing environment a plant has two sexes. Unfortunately for the people who grow these plants in captivity, the sex of the plant does not change but remain the same. A male is always a male and a female is always a female.
Therefore it should be a predisposition of the plant to keep a particular sex, whether it's given by sex hormones or X hormones nobody may know the genes encoding for the predisposition to have a male character or female character may still be constant.
Whether you can play with the expression of the genes and change the gender is a different story.
Now, going back to the original discussion if these sex hormone genes are mixed in any particular cross between two different species, we should get a very homogeneous distributions of these.

Gus
 
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