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09-17-2009, 05:35 PM
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Join Date: Sep 2009
Location: Cagliari, Sardinia, Italy
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thank you
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09-17-2009, 06:00 PM
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It's so beautiful!
Can I ask what you mean when you say "returned to type". I'm still a newbie to a lot of this terminology
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09-17-2009, 06:24 PM
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again a superb and envious plant. I can't tell from the picture but is this a smaller overall size? Do you have some rough dimensions?
Thanks again for your wonderful pictures of wonderful orchids.
Nick
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09-17-2009, 09:45 PM
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Quote:
Originally Posted by RosieC
It's so beautiful!
Can I ask what you mean when you say "returned to type". I'm still a newbie to a lot of this terminology
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Rosie, we are all here to share our experiences, so, please, don't hesitate asking whatever you want! If I don't know the answer, someone on the board certainly will!
When you cross two plants of a given variety, say two caeruleas for example (the type species then is lavender) two things may happen: or well the progeny is composed of caerulea plants, repeating the parents, or well the progeny is lavender. In this second case we say the plant got back to the type (lavender). Dominance and recessiveness are behind this and in general one cannot say what the progeny will be, unless the parents' genetic behavior is well known through previous crosses.
Quote:
Originally Posted by cirillonb
again a superb and envious plant. I can't tell from the picture but is this a smaller overall size? Do you have some rough dimensions?
Thanks again for your wonderful pictures of wonderful orchids.
Nick
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Not exactly, Nick. The plant may seem smaller, but that's because it is still young. Both plant and flowers are regular in size (plant about 30 cm hight, flower 15-17 cm across).
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09-18-2009, 05:52 AM
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Quote:
Originally Posted by Rosim_in_BR
Rosie, we are all here to share our experiences, so, please, don't hesitate asking whatever you want! If I don't know the answer, someone on the board certainly will!
When you cross two plants of a given variety, say two caeruleas for example (the type species then is lavender) two things may happen: or well the progeny is composed of caerulea plants, repeating the parents, or well the progeny is lavender. In this second case we say the plant got back to the type (lavender). Dominance and recessiveness are behind this and in general one cannot say what the progeny will be, unless the parents' genetic behavior is well known through previous crosses.
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Ok, I think I understand that. So in the above example there is a lavender recessive gene. A cross can end up with a full load of the lavender gene and so it shows up in the flower. When this happens you say it has 'returned to type'. If there is any of the dominant gene in the cross it will be the standard caeruleas.
Is that right?
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09-18-2009, 07:17 AM
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Rosim & Rosie, if I may interject. What Rosim says is true much or most of the time. Much of the time, the "type" variety is a lavender or lavender-pink.
However, the "type" variety is not necessarily always lavender. In general, in order for a variety to be recognized, it needs to be described by a trained taxonomist and recorded. In some cases of species varieties, the first described variety may not have been a lavender flower (or even the most commomly occurring color). For example, if the first flower found (and described) of a new species happened to be a semi-alba, then the semi-alba would be the "type" variety ... not the lavender variety. The lavender variety (if discovered and described later) may be more predominant, however, in that case, it would not be the "type" variety.
Since this occurrence is not too common, most of the time, when someone says the "type" variety (when referring to Cattleya species), it is understood to mean the lavender form (or the predominant color form if it is not lavender).
Is that confusing enough, Rosie?
Last edited by catwalker808; 09-18-2009 at 07:20 AM..
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09-18-2009, 11:49 AM
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Quote:
Originally Posted by RosieC
Ok, I think I understand that. So in the above example there is a lavender recessive gene. A cross can end up with a full load of the lavender gene and so it shows up in the flower. When this happens you say it has 'returned to type'. If there is any of the dominant gene in the cross it will be the standard caeruleas.
Is that right?
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What Catwalker says is completely right, but as far as Cattleyas are concerned, it is representative of few cases that can be considered exceptions. Let me try to put things in other words:
Consider a population of a lavender Cattleya and also consider that the described type of the species corresponds to a regular lavender flower from that population. Then, the dominant gene for color in that population is lavender.
Sometimes, some kind of mutation occurs and the recessive gene for a 'bluish' pigment has the opportunity to show up producing what we call variety caerulea.
Take two caeruleas and cross them (selfing one of them is the same). Two things may happen: the recessive genes for blue still continue to appear in the progeny, giving blue (caerulea) flowers, or the dominant genes for purple come back to dominance giving regular, type lavender flowers.
That’s what happened to this warneri cross, despite the fact that instead of two caeruleas (or selfing one caerulea) it was used a caerulea and an alba, in the hopes that the alba would not interfere with the blue pigment of the other parent. Sometimes this kind of cross (caerulea x alba) works well and produce caeruleas, but so many other times none of the two varieties repeat and the progeny gets back to type.
Hope I didn't make things more confusing!
Last edited by Rosim_in_BR; 09-18-2009 at 11:53 AM..
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09-18-2009, 12:27 PM
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Ah... got it now... I think.
The caeruleas colour is the recessive not the lavenda as I thought previously. The dominant and recessive colours can be different things but in this case that's the way round we're talking about.
My knowledge of biology is a bit shaky, but I thought that you only got the recessive colour if ALL the genes were for that colour. If there were ANY genes for the dominant colour then you would get the dominant colour.
That is from a simple example of human eye colour though, where everyone gets two genes and if both are the recesive you get that, if either one is the dominant you get that.
I'm guessing from what you have said that there are more genes involved here and that the percetage of them that are recessive needs to be over a certain level to get the recessive colour. Otherwise it would not be possible to cross a recessive with a recessive and get the dominant colour back... no matter... that's just my musings...
So the cross of two caerulea can come out with enough of the dominant gene to 'return to type'. The cross of an alba with a caerulea is more likely to 'return to type'. (Again just my musings, but this implies to me that the alba contains more of the genes for the dominant colour than the caerulea does and it MUST contain some of the caerulea reccesive gene).
OK, so you crossed a caerulea with an alba and the dominant lavender gene came back to the front, it 'returned to type'.
Got it. Sorry to have hijacked this thread, I might not be a biologist, but I studied physics at Uni and I always want to understand how things are working.
Last edited by RosieC; 09-18-2009 at 12:29 PM..
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