grafting lec12_0

8/7/2019 grafting lec12_0

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Grafting

Defn: connecting 2 pieces of plant tissue to grow as one

plant

Terms: scion: upper portion (usu. the shoot system)

stock: lower portion (usu. the root system)

interstock: stem piece between the scion and stock

budding: scion is reduced to a bud


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Reasons for grafting/budding

perpetuating clones that cant be maintained by other

asexual methods

obtaining the benefits of a rootstock

changing cultivars of established plants (usu. fruit

trees)

obtaining special plant forms

repairing damaged parts of trees

virus indexing


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Growth activity of stock/scion wood

for some methods, best results are obtained when both

stock and scion are dormant

for other methods, stock and/or scion wood needs tohave slipping bark


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Grafting Methods

Bench grafting

Field methods

Container or field methods

Repair grafting


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Bench grafting

Whip-and-tongue graft

Saddle graft


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Whip-and-tongue grafting

useful for small (1/4-1/2 in.) material, double working

(interstocks), root grafting, and bench grafting

splice grafting (the tongue is not made)

both stock and scion are dormant


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Figure 1 Figure 2A (top), Figure 2B (bottom)Figure 3A (left), Figure 3B (r ight)


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Saddle grafting

useful for machine grafting, bench grafting of grape

and Rhododendron

scion and stock should be the same size grafting is done when stock and scion are dormant,

then the completed graft is stored in a grafting case

until the graft union has healed


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Field methods

Cleft graft

Wedge graft

Bark graft

Four-flap graft


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Cleft grafting

useful for topworking fruit trees, crown-grafting

grapes

the best time is early spring, before active growth wedge grafting allows 1 more scion per stock


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Formation of successful graft unions: sequence of events

lining up of vascular cambia

the wound healing response

callus bridge formation new cambium formation

vascular tissue formation


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Bark grafting

Two types (rind and inlay-bark grafts) differ only in

prep of stocks bark, which should be slipping

often used in lieu of cleft graft later in the season


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Figure 23 Figure 24Figure 25 Figure 26


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Container or field methods

Side grafts

Approach grafts


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Side grafting

defn: (smaller) scion inserted into the side of a (larger)

stock

Types side-stub: nursery trees too large for whip-and-tongue, not

large enough for cleft

side-tongue: useful for broad- and narrow-leaved evergreens

(e.g., oriental arbovitae)

side-veneer: useful for small potted plants, e.g., uprightjunipers


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Approach grafting

two independent plants are grafted together

after union, the top of the stock and the base of the

scion are removed used when other methods are unsuccessful (e.g.,

Camellia)

often done on plants in containers

three methods: spliced-, tongued-, and inlay-approachgrafting


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Repair grafting

Inarching

Bridge grafting


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Inarching

used for repairing damaged roots of a full-grown tree

seedlings are planted around the tree during the

dormant season, grafting is done in the spring


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Bridge grafting

used for repairing a damaged trunk

early spring (with the bark slipping) is the best time

(dormant) scion wood should be 1/4 to 1/2 in. diam.


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Technique Date Use

Bark grafting Mid-April through mid-May Establish a pollinating variety on a limb of a treeor to completely topwork a tree.

Bridge grafting Mid-April through mid-May Repair trees girdled above the ground line.

Cleft grafting Late February and March Establish a pollinating variety on a limb of a tree

or to completely topwork a tree. Limbs should be

1 inch or more in diameter.

Inarch grafting Mid-April through mid-May Repair trees girdled at or below the ground line.

Also used if a root disease is suspected or feared.

Saw-kerf grafting February and March On peaches, nectarines and plums to completelytopwork a tree.

T-budding June through mid-September

Propagate actively growing rootstocks in the

nursery. May also be used to topwork apple and

pear trees up to 3 years old and 1-year-old peach,nectarine and plum trees.

Whip grafting February and early March Propagate 1-year-old rootstocks. May also be

used to establish a pollinating limb on a young,established tree.


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Fruit

Method

Propagation in Nursery Topworking Tree Repair

Apple Whip grafting, June budding ordormant budding

T-budding on trees

three years old or less,

cleft or bark grafting onolder trees

Bridge or inarchgraft

Peach, plum andnectarine

June budding or dormant Saw-kerf grafting Not normally done

Pear For propagating seedlings, whip graft,June budding or dormant budding

For propagating on quince rootstocks,

the interstem piece should be whip

grafted and the scion variety June or

dormant budded onto the interstem.

T-budding on trees 3

years old or less, cleft

or bark grafting onolder trees

Bridge or inarchgraft

Persimmon June budding, dormant budding orwhip grafting

Cleft graft or bark graft Bridge or inarchgraft

grafting lec12_0

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