Graft Incompatibility & Chimera
· 2026-10-02 21:59:29 · 3 views · 0 downloads
Graft incompatibility – Inability of the stock and scion to produce a graft union.
Types of Graft Incompatibility
1. Translocated G.I.
Incompatibility which cannot be overcome by insertion of mutually compatible interstock.
Cause: Restriction of movement of CHO across union.
Example: When inter-stock ‘Brompton plum’ introduced between Hale Early peach & Myrobalan – B plum incompatibility still present due to accumulation of starch at the base of Brompton plum inter-stock.
2. Localised G.I.
This incompatibility can be overcome by introduction of compatible inter-stock.
Cause: Improper contact between scion and stock.
Example: When Old Home introduced between Bartlett and Quince-C, the localized compatibility is overcome.
3. Delayed Incompatibility
Black line in walnut: When cultivar of J. regia are grafted as seedling of J. hindsi (Paradoax), the tree grows satisfactory for 15–20 years and after the problem arises.
Cause: A thin layer of cambium and dead tissues develop at one point and gradually extend around the tree at graft union until the tree becomes girdled, killing the plant but stock remains live.
Sapota also.
4. Partial G.I.
Mandarin grafted on trifoliate orange rootstock.
Causes of G.I.Mycoplasma: Pear decline disease in Bartlett tree grafted on P. pyrifolia.
When Jonathan apple grafted on EM-IX as rootstock, the scion developed Mo deficiency.
Allahabad Safeda grafted on Aneuploid No. 82 rootstock causes swelling above graft union.
ChimeraDefinition: An individual containing different types of cells.
Term: Hans Winkler (1907).
Cause: Spontaneous mutation.
Chimera or sports arise from genetic changes in the layers of the apical meristem.
Types of ChimeraMericlinal chimera: These are not stable in propagation.
Sectorial: Most common in horticultural plants but not stable.
Periclinal: Most stable form (vegetative propagation), e.g. blackberry.
Chimera are successfully utilized in ornamental plants.
Variation in leaves: Croton, coleus.
Bud sport: Starking Delicious, Richa Red.
Citrus sinensis + Citrus reticulate means this species is a chimera between two or is a result of protoplast fusion (cybrid).
Bud SportBud sport is one where a branch of a tree alone is found with genetic change from the rest of the part.
The characters of bud sport are inheritable.
They can be vegetatively propagated.
Example: Apple varieties – ‘Starking’ and Richared are bud sports from ‘Delicious apple’.
Mycoplasma: Pear decline disease in Bartlett tree grafted on P. pyrifolia.
When Jonathan apple grafted on EM-IX as rootstock, the scion developed Mo deficiency.
Allahabad Safeda grafted on Aneuploid No. 82 rootstock causes swelling above graft union.
Definition: An individual containing different types of cells.
Term: Hans Winkler (1907).
Cause: Spontaneous mutation.
Chimera or sports arise from genetic changes in the layers of the apical meristem.
Types of ChimeraMericlinal chimera: These are not stable in propagation.
Sectorial: Most common in horticultural plants but not stable.
Periclinal: Most stable form (vegetative propagation), e.g. blackberry.
Chimera are successfully utilized in ornamental plants.
Variation in leaves: Croton, coleus.
Bud sport: Starking Delicious, Richa Red.
Citrus sinensis + Citrus reticulate means this species is a chimera between two or is a result of protoplast fusion (cybrid).
Bud SportBud sport is one where a branch of a tree alone is found with genetic change from the rest of the part.
The characters of bud sport are inheritable.
They can be vegetatively propagated.
Example: Apple varieties – ‘Starking’ and Richared are bud sports from ‘Delicious apple’.
Mericlinal chimera: These are not stable in propagation.
Sectorial: Most common in horticultural plants but not stable.
Periclinal: Most stable form (vegetative propagation), e.g. blackberry.
Chimera are successfully utilized in ornamental plants.
Variation in leaves: Croton, coleus.
Bud sport: Starking Delicious, Richa Red.
Citrus sinensis + Citrus reticulate means this species is a chimera between two or is a result of protoplast fusion (cybrid).
Bud sport is one where a branch of a tree alone is found with genetic change from the rest of the part.
The characters of bud sport are inheritable.
They can be vegetatively propagated.
Example: Apple varieties – ‘Starking’ and Richared are bud sports from ‘Delicious apple’.