Propagation by GraftingPROPAGATION OF HORTICULTURALCROPS AND NURSERY MANAGEMENTSUBMITTED BY ; SUBMITTED TO;Kuldeep garwa Dr. L.N.Mahawar
GraftingDefn: connecting 2 pieces of plant tissue to grow as one plantIt includes the SCION which forms the above ground part of the grafted plant:AND the ROOTSTOCK which is the lower portion of the grafted plant which provides the root system for the new
GraftingAn INTERSTOCK or intermediate rootstock may be used with some fruit trees where a degree of incompatibility occurs:Interstocksare not normally needed with ornamental plants:Graftingwith interstocks is referred to as DOUBLE WORKING
Grafting The aim of grafting is to make clean cuts in the tissue of the two pieces so that the CAMBIUM tissues can be matched together: Cambium is the main layer of meristematic tissue in woody plants: It is located as a thin layer of tissue immediately under the bark in stem and roots:
The botanical limits of grafting Grafting within species: Grafting of species within the same genus: Grafting of different genera within the same family: Grafting between families:
Reasons for grafting plants Topropagate plants which cannot be economically propagated by other techniques Eg. Cultivars of ornamental shrubs and trees
Reasons for grafting plants Tocontrol the growth and performance of trees Eg. Apple and pear orchards Malling series rootstocks Malling 27, 26, 9
Reasons for grafting plants Toconfer resistance to pathogens to the grafted plant Eg. Waxflowers Eg. Avocados Eg. Grapes Eg.Tomatoes
Reasons for grafting plants Tobring fruiting plants into fruit production earlier in the life of the plant: All fruit crops which are commercially grafted: Fruit at 2-3 years
Reasons for grafting plants Grafting to obtain special effects in plants: Eg. Weeping standards Eg. 2 citrus fruits on the same tree Eg. Multicoloured rose plants
Reasons for grafting plants Grafting as an orchard management technique Eg.Top working of fruit trees to change varieties Eg. Frame working of fruit trees to assist pollination
Factors of importance in the healing ofa graft union Time of year Scion material at correct stage of growth Standard of carpentry Tying of the graft Growing environment
Polarity in grafting Correct polar differentiation of stock and scion must be maintained: The PROXIMAL end of the scion is fitted to the DISTAL end of the stock:
Selection of suitable rootstocks With woody The vigour ornamentals, most characteristics of the rootstocks used are rootstock usually closely related determine the size species to the scion: and vigour of the Many are seed grafted plant: propagated: This means that Easy to propagate many grafted shrubs and fast growing: grow to a large size:
Tying materials for graftingWith t-budding, simple rubber budding patches are often used:The rubber is biodegradable and they will disintegrate within 4-6 weeks:PVC budding tape is widely used but must be cut off after the graft union has formed:
Tying materials for graftingAt UQ Gatton we use the medical laboratory tape “PARAFILM”:This is a thin, stretchable tape which seals the graft union very effectively against the entry of water:It also degrades rapidly so it does not need to be removed:
Veneer Grafting Selection of Scion: Scion stick or bud stick should be healthy with swollen eye buds and 10 to 15 cm length and of pencil size thickness. Leaves are defoliated 8 to 10 days before cutting for grafting. Procedure Make a slanting cut up to 5 cm to the bud stick and same length deep notch to mango rootstock seedling. Put the cut part of scion in the notch of rootstock and tie with 1 cm wide polythene film tape.
Veneer Grafting Season: Veneer grafting should be performed in the month of September to October After Care Grafted plants / seedlings are kept humid and moist condition. Scion shoot starts sprouting in about 3 to 4 weeks. Polythene strip should be removed after the success of graft. Grafts ready for planting in 3 months. Success rate is 75 to 80 %.
Stone Grafting Selection of Scion: Scion sticks with 7 to 8 cm long from current year growth from healthy mother plants should be selected. Procedure Stone grafting operation should be performed in July- August months. Vertical cut of 3 to 4 cm is given on the rootstock and a corresponding wedge shaped cut is given on the scion. Wedge shaped cut on scion is matched with the cut on rootstock and then tied firmly with a polythene strip.
Stone Grafting After Care Remove the growing shoots from root stock and inflorescence from grafted scion immediately after emergence. Remove the polythene strip when union is formed and protect the graft from hot sun, pest and disease attack. Advantages Survival Success is more than 80 to 90 %, Requires less time and this Method is very suitable for coastal region.
1. Selection of bud sticks 3. Vertical Cut on Rootstock 2. wedge shaped Cut on Scion4. Grafting and Polystriping 5. Grafted Scion 6. Successful Grafts
Inarch Grafting Selection of Scion and Rootstock: Select one year old at least two feet long and healthy rootstock grown in pots / polythene bags. Root stock plant and scion stock plant sticks should have equal thickness. It should be from current year growth and from healthy mother plant Season August-September is best season for Inarch Grafting.
Inarch Grafting Procedure: Arrange the root stocks and scion tree on some platform or mandapam and Mark the grafting locations on stock and scion. Remove 5 cm long, 1 to 2 cm wide & about 0.2 cm deep slice of bark along with wooden part from stock and scion branches. Bring the cut surfaces together, cover the joint with a banana leaf sheath and tie them together with soft threads and cover joint part with cow dung plaster to protect from rain water.
Inarch GraftingAfter care Water the plants as and when required. Cut the scion from the parent tree after 2 to 3 months when the wound has healed. One week after separating the plant from root stock, the part of the rootstock above the graft is cut off. Keep the graft in semi shading area to harden the graft before transplanting into the main field.
Grafting Methods Bench grafting Field methods Container or field methods Repair grafting
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
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
Container or field methods Side grafts Approach grafts
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., upright junipers
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-approach grafting
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.
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.
Technique Date UseBark grafting Mid-April through mid-May Establish a pollinating variety on a limb of a tree or 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 completely topwork a tree.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.
The Biology of GraftingNatural grafting ◦ Bracing of limbs in commercial orchards to support weight of fruit ◦ Root grafting in woods is prevalent (CHO’s of upper canopy trees provide support for understory trees). This grafts only occur between trees of the same species ◦ Problems with root grafting include: transmission of fungi, bacteria and viruses between plants (Dutch Elm Disease spreads this way)
The Biology of GraftingFormation of the graft union ◦ A “de novo” formed meristematic area must develop between scion and rootstock for a successful graft union3 events ◦ 1) adhesion of the rootstock & scion ◦ 2) proliferation of callus at the graft interface = callus bridge ◦ 3) vascular differentiation across the graft interface
The Biology of Grafting Steps in graft union formation ◦ 1.) lining up of the vascular cambium of rootstock and scion. Held together with wrap, tape, staples, nails or wedged together ◦ 2.) wound response Necrotic layer 1 cell deep forms on both scion and stock Undifferentiated callus tissue is produced from uninjured parenchyma cells below the necrotic layer Callus forms a wound periderm (outer “bark”) which becomes suberized to prevent entry of pathogens Necrotic layer dissolves
The Biology of Grafting ◦ 3.) callus bridge formation Callus proliferates for 1 - 7 days Callus mostly comes from scion (due to basal movement of auxins and CHO’s, etc.) An exception to this is on established rootstock which can develop more callus than that from the scion. Adhesion of scion and stock cells with a mix of pectins, CHO’s and proteins. Probably secreted by dictyosomes which are part of the Golgi bodies in cells.
The Biology of Grafting◦ 4.) Wound-repair : First the xylem and then the phloem is repaired Occurs through differentiation of vascular cambium across the callus bridge Process takes 2 - 3 weeks in woody plants◦ 5.) Production of 2º xylem and phloem from new vascular cambium in the callus bridge Important that this stage be completed before much new leaf development on scion or else the leaves will wilt and the scion may die
The Biology of Grafting Some water can be translocated through callus cells but not enough to support leaves Cell-to-cell transport via plasmodesmata = symplastic transport (links cells membranes) Apoplastic transport is between adhering cells
Graft IncompatibilityCompatibility = ability of two different plants grafted together to produce a successful union and continue to develop satisfactorilyGraft failure: caused by anatomical mismatching/poor craftmanship, adverse environment, disease and graft incompatibility
Graft IncompatibilityGraft incompatibility from: ◦ Adverse physiological responses between grafting partners ◦ Virus transmission ◦ Anatomical abnormalities of the vascular tissue in the callus bridge
Graft IncompatibilityExternal symptoms of incompatibility ◦ Failure of successful graft or bud union in high percentages ◦ Early yellowing or defoliation in fall ◦ Shoot die-back and ill-health ◦ Premature death ◦ Marked differences in growth rate of scion and stock Overgrowth at, above or below the graft union Suckering of rootstock Breakage at the graft union
Graft IncompatibilityAnatomical flaws leading to incompatibility ◦ Poor vascular differentiation ◦ Phloem compression and vascular discontinuity ◦ Delayed incompatibility may take 20 years to show up (often in conifers and oaks)
Graft IncompatibilityPhysiological and Pathogen-Induced Incompatibility ◦ Non-translocatable = localized. Problem is fixed by using mutually compatible interstock(no direct contact between scion and stock) ◦ Translocatable = spreads. Interstock does not solve the problem. Some mobile chemical causes phloem degradation. Ex: cyanogenic glucosides like prunasin is converted to hydrocyanic acid (from Quince to pear)
Graft Incompatibility ◦ Pathogen-induced virus of phytoplasma induced ◦ Tristeza = viral disease of budded sweet orange that is grafted onto infected sour orange rootstock
Graft IncompatibilityCorrecting incompatible combinations ◦ Generally not cost-effective. Remove and top-work the rootstock ◦ Bridge graft with a mutually compatible rootstock ◦ Inarch with a seedling of compatible rootstock