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Thread: Is there species dominancy with hybrids

  1. #1

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    Hey Folks,

    I was wondering if certain species have more dominant genes when hybridizing than others. For example, Exotica's "Predator" between N. truncata and N. hamata appears to have more N. hamata features than N. truncata. I've also noticed that the N. aristolochioides hybrids tend to have more N. aristo characteristics than the other species they're crossed with. So does this mean that N. hamata and N. aristolochioides tend to have the more dominant genes compared with other species? Also do the male plants add more characteristics to the hybrid or vice versa?

    Thanks!
    Joel
    Nepenthes around the house

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    I bet it depends on the plant. Who was female and all that.

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    Geoff Mansell, who probably has more experience hybridising than anyone else, has made some observations in relation to this. He does note that it does make a difference depending on what species is the female, and which the male, parent. I think he has an article on his website.

    The other thing to consider is what you mean by dominance. Attributes that need to be considered are more than the physical attributes. The genes relate to the entirety of a plant's make-up, so you would have to consider temperature requirements, flower structure and size, leaf shape and structure, flowering time, growth habit and growth speed, light tolerance/preference, preferred medium etc etc etc. It is easy to look at specific traits, such as peristome or overall shape, but the devil would be in the detail. I'm not sure how much detailed work has been done on this.

    You'll also find variation within crosses. For example, I have several thorelii x aristolochioides grown from seed, and they show varying traits, some have pitchers with a strong aristo flavour, others are more influenced by thorelii. All my plants have the very strong tendency of thorelii to produce numerous basal shoots even early in growth. The colour is strongly influenced by thorelii, and the leaves and stem have a strong aristo look.

    Nor are certain species traits dominant with all other species. For example, northiana's peristome and shape will come out when crossed with a species like maxima or veitchii, but cross it with albo-marginata and it gets overwhelmed - if you've seen x cincta, it looks very similar to albomarginata.

    Anyway, it's an excellent point that will provoke some good discussion.
    Demystifying Nepenthes: http://www.nepenthesforeveryone.com

  4. #4

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    That was my point exactly. There's been discussion with regard to how certain hybrids might turn out. I've never heard of a "dominance" chart that might show that N. lowii tends to be more influential in hybridizing than say N. ventricosa. Or does N. maxima tend to be more influential than N. veitchii. Do highlanders have more influence when crossed with lowlanders? I'm curious because if I have one female plant in flower and multiple males, which plant might I choose to pollinate for certain features. I've heard of dominance in regards to breeding animals for example and wondered if that applied to Nepenthes as well.

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    Our observations have been so far are limited to a certain range of plants, but here is what we have noticed:
    N. ampullaria pitcher shape is dominant, both as the pod parent and pollen parent.
    N. albomarginata is dominant. Hybrids with the rubra (red) form seem to always be red.
    N. bicalcarata primary (or first generation) hybrids tend to be "plain" or not as spectacular as the pure species, but crossed back onto bical - interesting things can happen.
    Some species enhance the characteristics of others in hybrids, both pitchers and growth are usually benefited by N. thorelii and N. ventricosa - neither one being dominant, but seeming to pass on positive traits.
    Other groups seem to work well together, like veitchii, maxima, northiana, truncata, spathulata, and some others. (maxima is not more dominant than veitchii, they are very similar).
    Highland x lowland or lowland x highland, for the most part, have a wide temp tolerance. Sometimes a hybrid of two highland plants will have a wider temp tolerance than either parent.
    Anyone interested in hybrids would probably enjoy reading Geoff Mansell's article on his website (as Hamish mentioned).
    Just looking at Mansell's hybrid catalog photos is an education!
    A lot of the results have to do with the individual plants used for breeding.
    These are not the rules, just patterns we have noticed, that may not always be true 100 percent of the time. There is so much more to be done.

  6. #6

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    Joel,

    I doubt you'd come up with a hierarchy of dominance of species (as in lowii being more dominant that ventricosa). In any cross, 50% of genes come from each parent, so you'd have a 50/50 outcome in features. Some species may have a particular feature that is not dominant in relation to the same feature in most other species, but it might have a strong influence in another feature. Like human genetics, it could also not be so clear cut as dominance or recessiveness, there might be shades of grey. You might get compromises or interesting quirks. Some features generally do prevail in certain species (veitchii's peristome, thorelii's red colouring, truncata's size), but it doesn't always happen or not always to the same degree.

    It comes down to selective breeding (I think Trent has raised this before). You need to cross in the hope of a certain feature, and pick out the seedlings from the batch that have that feature, and dump the rest. Then you might choose to back cross or make an f2 cross to try to increase or finesse a feature. I think it was Keith Dodd who made a comment in his notes about having to make the same cross numerous times before you get the seedling you're looking for.

    Hamish
    Demystifying Nepenthes: http://www.nepenthesforeveryone.com

  7. #7

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    Hamish, where did Keith Dodd post notes? Do you mean Cliff Dodd?

    Also, N. rafflesiana pitcher shape seems to be dominant. Like the clipeata x rafflesiana (looks more like dad). N. rafflesiana x veitchii (looks like mom), N. even sibuyanensis x raff looks like a fat raff. This dominance seems to be more than 50 percent in these primary hybrids.

  8. #8

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    Cliff, sorry... I had a strong feeling the name wasn't right, but had to get back to the Hewitt v Nalbandian match and didn't bother checking LOL.
    Demystifying Nepenthes: http://www.nepenthesforeveryone.com

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