Re: Clones

 

Robert,

you have confused me, here. We may have misunderstood each other. My comments in italics.

Am 13.12.2012 19:56, schrieb Robert Pries:

Jamie; I agree with what you say but must take issue on one point. "Cultivar" does have a precise defined meaning. The International Code for Cultivated Plants (ICCP)Â gives a reasonbly precise definition with many examples. Botanical terms as you know are defined by The International Code of Botanical Nomenclature (ICBN), and you are correct when you say it (the ICBN)Âdoes not have a precise definition of cultivar, since that is not a botanical taxonomic term, but a horticultural term.

not sure where we went astray, here. We agree on these points. As I mentioned, the contraction of cultivated variety, cultivar, is not taxanomical, rather horticultural and has no weight, as it were and nothing directly to do with a clone. (more below)

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Clone is a scientific (specifically genetic)Âterm. It is not defined as a strictly taxonomic term and not defined by horticulturalists alone either,Âbut is essentially defined by all scientists and used throughout botanical-taxonomic and horticultural literature.

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we agree here, as well. Should include biological literature, as well. Although its use in any of these other fields MUST reflect the original genetic definition. It is not to be randomly used.

Jamie; I know you are the authority on Daylilies and perhaps all registered daylilyÂcultivars are clones. But clone and cultivar are not synonymous in other groups. Each cultivar may beÂa separate clone from the other cultivars. But In other groups cultivars can be either clones or seed strains. In Iris as I said most registered cultivar names designate a plant that is propagated vegetatively (a clone).


I must have been unclear, as a registered cultivar is a clone, it must be to be registered, but a clone may not be in cultivation, therefore not necessarily a clutivar. The two have little to do directly with each other, despite this association. For a cultivar to be true, it should be part of the original clone, otherwise it is a horticultural variety or strain, not a cultivar.

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Another way that clones are defined is products of asexual reproduction. That is why they are genetically unique. Individual offspring of sexual reproductionÂcan be called a clone if they are subsequently repoduced vegetatively (or tissue cultured) butÂuntil those idividuals are reproduced asexually we would generally not use the word clone for a single plant, but the set of plants thare are all genetic copies of each other. Progeny of a sexual cross would have different genetic makeup and while each individual could be called a clone upon asexually reproducing itself, collectivelyÂthe progeny of a sexual cross all have different genetics.


Here we have some disagreement. A clone is not defined by its method of reproduction! Although a clone is asexually reproduced, the original clone was not. It was the result of sexual reproduction or mutation. The original clone is not the offspring, rather the mother of the offspring, in asexual reproduction, which are clones of the original clone. This is where people become confused with clone. It is not the reproduction, it is the identification of the original genetic material. We refer to the original and its offspring as a clone. Singular. Genetically identical. Identifiable. Cloning is the asexual reproduction of the clone and this off-spring are clones. It is not the clone itself.

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I think we may have confusion with these terms becomes they are all used in different contexts where sometimes they may appear to be synonymous but really each has a special defined meaning.

Darlene I hope you are not totally confused. I live in NC also near Durham, Where are you?


I think Darlene is completely lost at this point. We are all a bit mad, don't you think?

Jamie

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Am 12.12.2012 23:37, schrieb Darlene Moore:
Jamie,

You mean there aren't any registered (registered with some governing 
body) daylily that didn't come into being by sex!  I thought one could 
pollinate daylilies and then the plant grown from the seed would not be 
considered a clone.

Darlene
Darlene,

although that was not the point I was aiming for, as far as I know, there are no registered daylilies that were asexually produced. If there were, they would be stabile mutations that were then registered.

I think we need to step back a bit. The concept of clone is much simpler than many of you are believing. A clone is ANY unique genome. An example; we have just crossed two plants belonging to different genetic make-up (two different clones) or not. This doesn't matter. They produce seed. We raise this seed to new plants. Each of these off-spring are clones. Genetically unique units. Every seed will produce a unique clone. The only exception to this is apomixis, which is found in certain plants, such as the genus Sorbus, i.e., or parthenogenisis in the animal world. We may choose to name some, as we have found them of quality, or we may decide to use them as parents for another generation. This later group would typically be refered to as Clone 1, Clone 6, Clone 12, etc. as a method of identifiing them. All of these offspring are genetically unique. All are individual clones.

As you see, it is a very simple definition. The confusion has arisen due to the romance involved with the word. Also, depending on your profession, the word may be used in a more specialised manner, yet the definition is still the same. A unique genetics.

Another item we are bantering about are the terms variety, forma and cultivar. These have been recently sorted for nomenclature. The word variety is now rarely used botanically, with forma prefered. A forma is a described variation of an otherwise defined unit. Thus, a taxon. A variety is anything, more or less, that can be seperated from others. This has nothing more to do with taxon, clone, etc. One can say the red varieties, the short varieties, the hardy varieties. It is very general. This leads us to cultivar, which is the contraction of cultivated variety. In other words, a variety that is identified and further cultivated. It has no official meaning, although it is amply used to speak/write of plant breeding/marketing, and so on. It is not to be confused with a strain, which is a defined, non-clonal group of organisms. It has variation, yet, enough qualities in common to be placed under a strains definition/description. Snapdragons, petunias, zinnias, etc are available as strains, as are many plants.

-- Jamie V.
_______________________
KÃln (Cologne)
Germany
Zone 8 


-- 
Jamie V.

_______________________

KÃln (Cologne)
Germany
Zone 8

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