Agriculture Reference
In-Depth Information
The graft union, grafting
and budding
Introduction
Grafting is the art of connecting two pieces of living tissue together in such a
way that they unite and grow as one. In apples and pears it is generally used
to combine a scion (fruiting) cultivar with a rootstock. Budding is a special
form of grafting in which the initial scionwood component is reduced to a
single bud.
This art has been practised for thousands of years, Garner (
) noting that
grafting with detached scions was used by the Chinese before
BC. It was
described by writers in ancient Greece and Rome and very widely employed
in western Europe in the Renaissance period and subsequently.
The main purposes of grafting are to assist in the propagation and perpet-
uation of clones that cannot readily be propagated by other asexual means,
and to enable the production of composite trees from rootstocks and scions
each of which possesses specific and distinct desirable attributes. It is also used
to change scion cultivars in established orchards, to hasten the fruiting of
seedling selections in breeding programmes and as a research tool in the study
of physiological processes and viruses.
Formation of the graft union
The formation of the graft union can be considered as resulting from the
wound-healing processes which take place on the cut surfaces of the rootstock
and scion, operating in the context of close contact between surfaces. The
unionisaccomplishedentirelybycellsthatdevelopafterthegraftingoperation.
The sequence of events is as follows.
The placement of freshly cut scion tissue in intimate contact with similar
freshly cut stock tissue in such a way that their cambial regions, capable of
