Graft-chimera

In horticulture, a graft-chimaera may arise in grafting at the point of contact between rootstock and scion and will have properties intermediate between those of its "parents". A graft-chimaera is not a true hybrid but a mixture of cells, each with the genotype of one of its "parents": it is a chimaera. Hence, the once widely used term "graft-hybrid" is not descriptive; it is now frowned upon.

Propagation is by cloning only. In practice graft-chimaeras are not noted for their stability and may easily revert to one of the "parents".

Nomenclature

Article 21 of the '' ICNCP'' stipulates that a graft-chimaera can be indicated either by
* a formula: the names of both "parents", in alphabetical order, joined by the plus sign "+":
: ''Crataegus'' + ''Mespilus''
* a name:
** if the "parents" belong to different genera a name may be formed by joining part of one generic name to the whole of the other generic name. This name must not be identical to a generic name published under the ''International Code of Nomenclature for algae, fungi, and plants'' (''ICN''). For example + ''Crataegomespilus'' is the name for the graft-chimaera which may also be indicated by the formula ''Crataegus'' + ''Mespilus''. This name is clearly different from ×''Crataemespilus'', the name under the ''ICN'' for the true hybrid between ''Crataegus'' and ''Mespilus'', which can also be designated by the formula ''Crataegus'' × ''Mespilus''.
** if both "parents" belong to the same genus the graft-chimaera may be given a cultivar name. For example ''Syringa'' 'Correlata' is a graft-chimaera involving ''Syringa vulgaris'' (common lilac) and ''Syringa × chinensis'' (Rouen lilac, which is itself a hybrid between ''S. vulgaris'' and ''S. persica''). No plus sign is used, because both "parents" belong to the genus ''Syringa''.

A graft-chimaera cannot have a species name, because it is simultaneously two species. Although +''Laburnocytisus'' 'Adamii', for example, is sometimes seen written as if it were a species (+''Laburnocytisus adamii''), this is incorrect.

In Darwin's works

Charles Darwi
"The Variation of Animals and Plants Under Domestication"
, 1868 г.:

I will therefore give all the facts which I have been able to collect on the formation of hybrids between distinct species or varieties, without the intervention of the sexual organs. For if, as I am now convinced, this is possible, it is a most important fact, which will sooner or later change the views held by physiologists with respect to sexual reproduction. A sufficient body of facts will afterwards be adduced, showing that the segregation or separation of the characters of the two parent-forms by bud-variation, as in the case of Cytisus adami, is not an unusual though a striking phenomenon. We shall further see that a whole bud may thus revert, or only half, or some smaller segment.

See also

* Bizzaria – a very popular graft chimaera in ''Citrus''
*
* Grafting

References

{{Reflist

Botanical nomenclature