1. Principles of Grafting and Budding
Chapter 11

2. Grafting & Budding Terms
Graft: Two living plants connected and growing as one
Scion: Dormant shoot, upper portion of graft
Stock: Lower portion of graft, root system

3. Grafting & Budding Terms
Bud: Similar to graft, but scion is reduced to
a single bud

4. Grafting & Budding Terms
Interstock: A middle or intermediate
stem piece located between scion & stock

5. Grafting & Budding Terms
Vascular Cambium: Meristematic tissue between xylem & phloem X P
Vascular
Cambium

6. Grafting and Budding Perpetuate clones Rootstock effects
Changing cultivars
Rapid maturity
Shortens juvenility
Used for breeding programs
Special growth forms
Damage repair
Studying viruses

7. Seedling Rootstocks Simple Cheap Disease free Better root systems
Genetic variation

8. Clonal Rootstocks Source Characteristics Stool beds Cuttings
Tissue Culture
Characteristics
Uniformity
Disease Resistance
Growth Habit
Flowering Habit
Scion rooting
Disease potential

9. Rootstock benefits Interstock benefits
Disease resistance
Soil tolerance
Size control
Fruit quality
Interstock benefits
Overcome incompatibility
Add additional attributes
Dwarfing

10. Topworking
Change cultivars
Add pollinators

11. Topworking
Multiple varieties on one tree

12. Formation of graft union
Line up vascular cambium
Wound healing response
Necrotic plate
Callus bridge formation
Cambium formation
Vascular tissue formation

13. 1. Close Vascular Contact
55-90F
Active cambium
High humidity
Pathogen free
Mechanical support
Cambium ‘matching’

14. 2. Formation of Necrotic plate
Cells killed when
cut is made

15. 3. Callus Bridge Formation
Production & Interlocking of parenchyma
Comes from phloem and immature xylem
Stock produces most callus

16. 4. New Cambium Formation
Adjacent callus differentiates to form cambium
Cambium forms across bridge of callus tissue

17. 5. New Vascular Tissue (X&P) From New Cambium
Vascular system must be in place before bud break

18. GRAFT FORMATION

19. BUD FORMATION

20. Factors of graft healing
Incompatibility
Species or variety (cultivar)
Temperature
Moisture
Oxygen
Growth status (active vs. dormant)
Technique or type of graft
Disease situation

21. Polarity in grafting Distal and Proximal ends
Reversed polarity works only for a limited time with grafts
Nurse-root grafting
Buds can be reversed
Can cause a wide crotch angle as it grows - strong

22. Limits of grafting Generally limited to dicots & gymnosperms
More closely related the better
Permanent grafts in monocots are not successful
Likely has a lot to do with cambium and vascular tissue production
Common between same species
Apple on apple
Harder between different Genera in same family
Tomato on potato (Solanaceae family, or Nightshade)
Rare between families

23. Symptoms of Incompatibility
High failure rate
Yellow foliage, early defoliation
Premature death of scion
Differences in growth rate
Not always a sign of incompatibility
Can be differences in genetic potential for growth rate
Overgrowths
Breaks at graft union

24. Types of Incompatibility
Localized
At site of graft contact
Translocated
Substances moved from the scion to rootstock or vice-versa
Virus present

25. Incompatibility Cause: Genetic Mechanism (example theories):
Chemicals found in one partner may be toxic to the other (Cyanogenic glucoside)
Lignification of cell walls may be inhibited

26. Effects of Rootstocks on the Scion
Size and growth habit
Fruiting
Size, quality, and maturity of fruit
Winter hardiness
Disease resistance
Timing of fruit maturity
Effects of Scion on the Rootstock
Vigor
Cold-hardiness

27. Effects of Interstock on Stock & Scion
Reduces stock and scion size
Direct effect, not indirect
Mechanisms of effects (theory)
Translocation (stem)
Absorbing ability (root system)
Interaction of all parts

28. Factors influencing growth of grafted plants
Nutrition
Translocation
Endogenous growth factors