Note for HORT 101 with Professor Bosela at IPFW
Note for HORT 101 with Professor Bosela at IPFW
Popular in Course
Popular in Department
verified elite notetaker
CSCI A110: Intro to Computers and Computing
verified elite notetaker
verified elite notetaker
One Day of Notes
verified elite notetaker
This 13 page Class Notes was uploaded by an elite notetaker on Friday February 6, 2015. The Class Notes belongs to a course at Indiana University taught by a professor in Fall. Since its upload, it has received 14 views.
Reviews for Note for HORT 101 with Professor Bosela at IPFW
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 02/06/15
GRAFTING AND BUDDING Grafting and budding are related processes Both involve the physical joining of two or more plants with the goal of producing a single physiologically integrated plant However in budding the grafting partner that is used to produce the shoot system of the new plant termed the scion consists of a single bud rather than a whole branch or branch section with multiple buds For grafting to be successful the vascular cambia of the grafting partners must grow together ensuring that the vascular tissues xylem phloem produced post grafting are continuous between both partners Grafting is one of the oldest forms of plant vegetative propagation dating back to 1000 BC In developed countries grafting is also one of the most expensive propagation techniques since it is intrinsically labor intensive However for some plants e g red oak black walnut reliable vegetative propagation is only possible through grafting Grafting especially between tree roots can occur spontaneously under natural field conditions but both trees typically maintain separate root and shoot systems In contrast in greenhouse and nursery propagation separate plants are used to produce the roots and shoots of the new plant These plants are tenned the rootstock understock and scion respectively Fig 1 Although grafting is generally considered a form of cloning since the phenotype of the scion is preserved in the new plants at a higher frequency than is possible in most other types of vegetative propagation However the root and shoot systems of grafted plants are generally genetically distinct and may even be from different species This genetic variability is often advantageous since rootstocks can be used to contribute additional traits e g disease resistance stress tolerance cold tolerance growth control dwarfing etc that would not be possible if the scion had been propagated on its own root system In fact for several fruit and nursery crops the phenotypes conferred by the rootstock are so important that the rootstocks are clonally propagated In doubleworking three plants are combined a scion a rootstock and an interstock Interstocks which are placed between the scion and the rootstock are routinely used for height control e g to produce tree roses Interstocks can also be used to prevent graft incompatibility Collectively a large number of grafting and budding techniques have been developed This diversity is largely a re ection of the divergent grafting preferences of plant taxa with the optimal grafting technique frequently varying between species In addition several specialty grafting techniques have been for use within the orchard industry eg bridge grafting for the repair of damaged stems top working for tree conversion between cultivars etc Compared to other popular vegetative propagation techniques stem cutting propagation layering etc grafting is technically more challenging and also more sensitive to differences in the physiology and growth condition of the stock plants As a consequence of these difficulties grafting is sometimes jokingly referred to as an art more so than a science However there are several generalizations that can be made about variables that contribute to grafting success First off the stock plants used must be healthy diseasefree as is true of any vegetative propagation technique The tools used for grafting knives wedges etc should be wellmaintained sharp and sterilized before each use At a mechanistic level grafting cuts should be long even and wellmatched and the graft junctions should be well wrapped to ensure close contact between the grafting partners and to prevent dessication In addition the vascular cambia of the scion and rootstock must be properly aligned to facilitate their intergrowth Fig 2 Proper aftercare is also important especially for grafts involve partners differing significantly in diameter where the initial graft junctions are liable to be structurally unstable For trees and shrubs timing as it relates to the developmental state of the scion and rootstock at the time of grafting is also an especially important variable In general grafting is done in the Spring as growth is resuming for the year but it is important that the degree of activation is greater for the rootstock than the scion To ensure this growth differential the scionwood is generally collected in the Fall or early Winter and stored in a refrigerator until the time of grafting Cold storage ensures that the buds are exposed to the low temperatures required to break their dormancy but prevents growth resumption In contrast the rootstocks in either the field or greenhouse are exposed to warm temperatures prior to grafting The goal is to graft onto rootstocks to have resumed their growth just prior to or shortly after the point of grafting The more active state of the rootstock allows for sap ow to the grafting site and wound healing prior to the onset of growth resumption in the scion which will die if begins to grow too early before functional vascular connections have formed between the rootstock and scion For grafts that require bark slippage veneer grafting Tbudding etc the rootstocks must be actively growing at the point of grafting for bark peeling see the term list below In this lab you will practice several of the most common grafting and budding techniques We will initially work with herbaceous plants tomato and potato since nonwoody stems are easier to cut and there is less chance of injury However you will also have the opportunity to practice both grafting and budding with apple Grafting Terminology Scion 7 a whole branch or section of a branch usually from last year s growth that is used to propagate a plant The scion gives rise to all or part of the shoot of the grafted plant A budstick is a section of stem used as a source of buds for budding Roostock Understock 7 the portion of a graft to which the scion is attached It may be a piece of root a seedling or a tree with part of the top removed in preparation for grafting Interstock 7 a piece of stem that is grafted between the rootstock and the scion Bark slippage bark peeling 7 A condition that is diagnostic of periods of rapid cell division in the vascular cambium of a stem or root As a consequence the cells are loosely adherent and the bark can be pulled peeled off The vascular cambium is generally removed with the bark Top working 7 any grafting that involves the use of larger understocks as in the case of grafting onto the limbs of an established tree Topworking can be used to combine multiple varieties on the same tree or for orchard conversion ie following severe pruning Top working can also be used to facilitate sexual reproduction eg male branches may be grafted onto female trees to produce to create bisexual plants etc Double working 7 any grafting the involves the use of an interstock such that the shoot of the grafted plant is derived from two separate plants one which contributes to the basal regions of the shoot and a second which contributes to the crown Vascular cambium 7 a cylinder of meristematic cells located between the secondary xylem wood and the secondary phloem The vascular cambium produced the secondary xylem and phloem Callus 7 a mass of rapidly dividing cells that is not involved in the production of organized organs Under natural eld conditions callus tissues are generally produced at injury sites presumably as a result of hormonal imbalances and are involved in would healing In grafting callus production is an essential step in the formation of the graft union Healing over 7 the process by which a functional connection is formed between the grafting partners Graft healing involves three stages 1 proliferation and interlocking of callus cells at the junction of the scion and rootstock to form a callus bridge 2 adhesion of the scion and rootstock via the formation of strong connections between the callus cells and 3 vascular tissue differentiation across the callus bridge In general the scion contributes disproportionately both to callus formation and vascular differentiation In addition the vascular cambia of the grafting partners must be physically aligned for the formation of effective vascular connections Graft incompatibility 7 a phenomenon whereby grafts fail to take not as a result of poor grafting technique but rather as a result of a lack of stable physiological integration In general the more distantly related the plants being grafted the more likely they are to be incompatible However the relationships are often complicated with graft compatibility depending upon which partner is assigned as the rootstock or scion Graft incompatibility may occur after months or years of growth in which case the incompatibility may be related to differences in growth rate Types of Grafting Cuts Slice cuts 7 made using the arm and shoulder to pull the knife towards the grafter as in splice or whip grafting Splice cuts can also be made away from the grafter but the cutting angle is more difficult to control Cross cuts 7 the grafter s arm and knife are rotated using the thumb as a pivot with both hands being joined to prevent the knife from cutting the grafter Binding Materials used in Grafting Budding rubbers 7 strips of rubber that can be stretched and used to try grafts Budding rubbers deteriorate within a matter of weeks when exposed to the light and temperature conditions Graftingbudding tape 7 Polyethylene or polyvinyl chloride PVC strips They must be tied by the grafter and physically removed following graft healing to prevent girdling Nursery adhesive tape similar to surgical adhesive tape but nonsterile Adhesive so self tying but must be removed following graft healing ParafilmTM 7 a deformable plastic film Parafilm is selftying and also generally water impermeable alleviating the need for waxes or tars to limit water loss Parafilm is not strong enough to restrict subsequent plant growth and thus does not present a girdling risk NOTE Waxes or tars are frequently applied after binding the graft union both to prevent water loss and pathogen ingress I Tomato Potato Grafting In this exercise we will graft tomato scions onto potato rootstocks Tomato and potato are in different genera Solanum vs Lycopersicum but the same family Solonaceae and are easily grafted The resulting plants affectionately termed pomatoes may produce both tubers and berries tomato fruits but it has been suggested that grafting adversely affect the taste of both In this exercise you will prepare both cleft grafts and whip and tongue grafts Plant Material Red Potato Solanum tuberosum 45 wk old potato plants that were produced vegetatively from seed potatoes are provided Seed potatoes are whole tubers or sections of tuber with one or more axillary buds eyes that give rise to new plants Tomato Lycopersicum esculentum Summerpink VF 56 wk old tomato seedlings are provided Summerpink is a determinate bush cultivar and thus does not require staking A Cleft Grafting Protocol 1 Obtain two pairs of potato and tomato stockplants for grafting One of the pairs should be of equivalent diameter at the anticipated grafting sites approximately 1015 cm below the growing tip on the tomato seedlings and 310 cm above the base of the potatoes For the other pair the scion should be smaller in diameter than the rootstock 2 Working one graft at a time use a sharp razor blade to decapitate the potato rootstock 310 cm above soil level Cut the stem perpendicularly transverse cut at an intemodal position 3 Use the same razor to make a 23 cm long median longitudinal incision cleft in the top of the rootstock NOTE A longitudinal cut runs parallel to the long axis of the organ while a median cut runs though the middle of the organ being section 4 Cut off the tomato scion approximately 10 15 cm below its growing point Remove all of the leaves except the distalmost two to four to limit the amount of leaf surface for water loss 5 Make opposite oblique longitudinal cuts at the base of the scion that met to create a wedge The cuts should be prepared at a low angle sloping cuts so that their length matches that of the rootstock cleft 23 cm to create a large surface area for contact with the rootstock 6 Insert the base of the scion into the cleft at the top of the rootstock and position the base of the scion to ensure maximal contact between the cut surfaces of both partners If the scion is smaller in diameter than the rootstock as for your second graft position the scion towards one side of the rootstock to align the vascular cambia of the rootstock Fig 3 Oblique means at an angle other than transverse or longitudinal An oblique longitudinal cut is oblique but approximates a longitudinal cut 7 Wrap the graft union in Para lm starting on the rootstock below the point of grafting and proceeding onto the scion You should have enough Para lm to reverse direction and double wrap the graft The Para lm will hold the scion in place until adhesion and tissue intergrowth have occurred at the graft junction The Parafilm also maintains a high humidity at the graft union 8 Obtain two bamboo stakes 1520 cm taller than the height of the grafted plant and place in opposite sides of the pot with the grafted plant 9 Obtain a clear plastic bag and wet its inside slightly by misting with a water sprayer bottle Place the bag over top of the grafted plant using the bamboo stacks as a guide and seal the bag around the base of the pot with a rubber band 10 After you have finished grafting place the plants under indirect light or on an open greenhouse bench with 50 shadeclothe 11 After 7 days remove the rubber band and loose the base of the bag to start to lower the humidity experienced by the plant Sprouts from the rootstock which may appear watersoaked as a result of the high humidity levels should be pinched off at this time Adventitious roots may be present at the base of the scion The roots do not need to be manually removed since they will eventually air dry 12 After an additional 34 days the bags can be completely removed However it is best remove the bags at the end of a day so that the plants will have several hours to adjust to the ambient humidity prior to addition of an illumination stress The parafilrn will break as the plants increase in diameter B WhipandTongue Grafting The whip and tongue graft is one of the most popular types of grafts Whip and tongue grafts are most effective when used with to join plant less than 1 cm 25 cm in diameter with one year old seedlings being the most common rootstocks Grafting take is facilitated by the multiple long wound surfaces on each grafting partner In addition since the grafting partners are generally the same diameter the graft union tends to be relatively strong and stable Protocol Obtain two pairs of tomato and potato plants for grafting Both members of each pair should be approximately the same diameter at the anticipated grafting point see Step 1 in the cleft grafting protocol Using a singleedged razor blade prepare the grafting cuts as illustrated in the whipandtongue diagrams provided at the end of this handout Fig 4 The grafts will be sealed with Parafilm and the plants will be covered with plastic for humidity control as described for the cleft grafting protocol C Aftercare and Evaluation To produce both tomato and potato crops the grafted plants should be planted in a garden or transferred to larger pots provide sufficient room for tuber formation Continue to remove rootstock suckers as they develop as they will compete with the tomato scion for resources Tubers will form naturally after 23 months of growth irrespective of the photoperiod If you have multiple plants you may want evaluate the effect of fruit thinning on tuber yield since the processes of fruit development and tuber growth may compete for resources 11 Apple Grafting Plant Alaterial Since I was unable to locate a supplier of apple rootstocks that ships early enough in the Spring for this lab we will use grafted apples as our rootstocks The grafted cutlivars Sun Fuji and PioneerMac were kingly provided to IPFW at cost by Adams County Nursery Aspers PA wwwacnurserycom The Sun Fuji are grafted on M9Nakb337 rootstock and the PioneerMac are grafted onto Bud9 rootstocks Both rootstocks are dwalfmg and are adapted to a wide variety of soil types For each cultivar the rootstocks are two years old and the scions are one year old Before starting your own grafting today you should examine the trees to locate the graft union and to try to detennine the type of grafting or budding technique employed The apple trees were shipped as bareroot planting stock in early February They were stored in a refrigerated room for about one week warmed to room temperature and planted on 2 152 1606 using 610 inch plastic pots and standard peatbased potting media Each tree was numbered sequentially 125 for each cultivar and cut back 12 feet above soil level The top portion of each tree was labeled and placed into cold storage to be used as scionwood for our grafts The planted trees have been maintained in the greenhouse with supplemental lighting from dusk to 9 pm and 5 am to dawn to provide a 16 hr photoperiod Protocol 1 Select two apple trees for grafting Each tree will be labeled to indicate the cultivar and the speci c tree number 125 Add you name to the label and locate the top portion of each tree from the scionwood bag The tops of each tree were cut off at the time of potting 2 Prepare cuts as shown in the illustration at the end of this handout Fig 4 starting with the rootstock Although slice cuts are normally made by pulling the knife towards the body of the grafter to minimize your risk of injury you should prepare your cuts by running the knife away from your body To facilitate the cutting of the rootstock you may need to place the rootstock on its side or partly upside down If you are not able to make a suitable cut on your st try ie 1 to 2 inches long straight and angled across the stem can cut back further on the rootstock and try again at a lower position on the stem 3 Prepare equivalent cuts at the base of the corresponding scionwood branch Once you have prepared suitable cuts use the pruners to isolate a 45 inch long section of the scionwood branch that will be used for grafting The remaining distal portions of the branch which will be used for budding should be labeled and saved 4 Fit together the rootstock and scionwood If you were able to make good cuts in your rst try for each grafting partner the diameter match should be perfect However if you needed multiple tries to make the cuts the rootstock will be greater in diameter than the scionwood and you will need to align the vascular cambia of the grafting partners on a single side After your alignment has been checked by the instructor use the budding rubbers provided to wrap and tie the grafts The budding rubbers should cover the entire length of the graft using multiple rubber strips if necessary and should be tied tightly to maintain good contact between the wounded surfaces of the grafting partners a concern that is especially important when learning grafting and the cuts are not perfectly straight 5 After the grafts have been tied seal each with grafting tar TreeKote The scions may also be wrapped in plastic bag with a small amount of moist sphagnum peat moss to stimulate growth from the buds of the scionwood The bags will help to moisten and warm the buds 6 Remove all shoots from the rootstock by pinching and return your trees to the greenhouse Your grafts should be examined at least once a week to remove any new rootstock shoots that have formed Once scionwood bud growth is apparent the plastic bags place around the scions should be removed New shoots will continue to develop from the rootstock and will need to be removed on a regular basis If these shoots are not removed they will divert mineral nutrients and hormones away from the scion adversely affecting its healing and growth III Chip Budding of Apple Whereas grafting utilizes a scion consisting of a short piece of stem tissue with multiple buds budding utilizes individual buds isolated with a small section of subtending stem tissues Budding offers several advantages compared to grafting Budding is more economical since a single bud is used per propagation In addition budding is generally possible at multiple times during the growing season Spring Summer and Fall at least for chip budding Bud healing occurs more quickly than graft healing and the graft union is generally stronger at least for the first few years Budding is technically simpler than grafting Budding cuts are easier to make than grafting cuts the process of cambial alignment is facilitated by the size differential of the grafting eXplants and bud unions are easy to tie and seal As with grafting several distinct budding techniques have been developed the most poplar of which include patch budding Tbudding and chip budding Patch budding and T budding require bark slippage and thus are only possible in the Spring In contrast since chip budding does not require bark slippage and therefore can be performed at nearly any time during the growing season however success rates are generally highest in the Spring and Fall When chip budding is done in the Spring or Summer the branch or seedling that was used for grafting is typically cut off beyond the point of bud insertion after 1015 days provided that the buds have taken as assessed based on their color and degree of turgidity to force shoot growth from the bud In Fall budding the branch or seedling is cut off the following spring before the rootstock has resumed its growth Protocol Decide which cultivar Sun Fuji or Pioneer Mac you want to use for the scionwood See Plant Materials under Section II Apple Grafting above Fuji apples are sweet and crisp and one of the most popular eating apples MacIntosh apples have a more tart taste but also can be eaten directly or used for baking Select a tree rootstock of the opposite cultivar Locate a scionwood branch of the appropriate cultivar and follow the instructions provided in the diagram provided at the end of this handout Fig 5 You can bud twice on the rootstock on opposite sides of the stem The buds can be added at more or less any position on the rootstock provided nodes are avoided you are above the point of original grafting and are leave at least a few inches of space between the top of the rootstock and the buds Only the healthiest buds on the scionwood should be used and the bud chips used should exactly match those removed from the rootstock in both shape and size If the match is not perfect be sure to align the vascular cambia of the bud chip with the rootstock cambium on at least one side Wrap with parafilm from the top to the bottom so the bud chip does not pop out The bud itself should not be wrapped or tears should be made at the position of the bud following wrapping so it is open to the air Review Questions 1 For the potatotomato grafting experiment can you explain the production of adventitious roots at the base of the scion in terms of what you have learned in class about activity and transport of auXins 2 Can you think of any possible advantages to taproot grafting where the scion is grafted into the taproot of the rootstock 3 Some types of apple cultivars are selfinfertile and require pollinizers Can you think of a way grafting top working could be used to overcome these problems 4 Most of the callus that forms at the graft union is thought to be derived from the scion With this in mind can you account for the popularity of hot pipe grafting techniques in which the graft unions are placed on top of PVC pipes that are heated with circulating hot water The air temperature in contrast is generally kept cool 5060 0F gures and Illustrations In Gm ing Termlnology 39Bark39 Periderm Codex Phloem and Vascular cambiurn 39Wood39 Seoondaryxytem andpim fmesem Figure 2 Steps in gra union healing 1 Stock wilh Cle ZV Scion 3 Sciun inscrlud in Clef of Stock Figure 3 Cleft gra ing illustrations PREPARING THE STOCK PREPARiNG THE SClON A long sloping cut 25 to 6 cm 1 to 22 in long is made at the top of the stock A second downward cut is made starting one third of the distance from the tip to the base of 4 the first cut A long sloping cut is made at the base of the scron the same length as the cut on the stock Pulled apart it looks like this i l A second cut is made under the first just as for the stock The stock and soion are slipped together the tongues interlocking Figure 4 Whipandtongue grafting procedures illustrated ROOTSTOCK STEM Side View A A 45 cut is made in the rootstock about onequarter of the way through the stem CHIP REMOVED Side View C The chip produced by the two outs is removed SECOND CUT START SHARPLY AT THE TOP TO GO IN DEEP QUICKLVr Front View Side View B A second cut ts made starting about 1 12 Inches above the first cut and extending down to meet the rst cult Cut deeply enough at the top so an upside down U39 form is made A cut that is made too shallow results in an quotAquot shape BUD BUD F39RST CUT FIRST CUT Front View Side View D The bud to be inserted is cut item the bud stick exactly as the chip was removed trom the rootstock lt BUD 5 BUD CHIP 0F WOOD Side View Front View I i F The bud ts removed trom the bud suck E Second cut on the bucL BUD Q g BUD TIE gt a ROOTSTOCK Side Wew NOTE Be sure to align the cambturn al the bud and the wctstock on a least one side G The bud is inserted in the rootstock and tied with rubber bud tie Figure 5 Chip budding procedures illustrated TBuddlng mMg 14mins FIGURE 1116 Top Tissues involved in healing of an inserted Tbud as prepared with the quotwoodquot xylem attached to the scion bud piece Graft union formation occurs when callus cells developing from the young xylem of the rootstock inlen39ninglc with callus cells forming from exposed cambium and young xylem of the T bud piece As the bark is li ed on the rootstock for insertion of the bud piece it detaches by separation of the youngest xylem and cambial cells Bailout A cross section of a chip bud CB 39llbud TB and rootstock RS Because the chip bud substitutes exactly for the part of the rootstock that is removed the cambium of the roots and scion are placed close together resulting in a rapid and strong union When a T bud right is slipped under the quotbarkquot the cambium of the rootstock and scion are not adjacent and the initial union formation can be weak and slow Redrawn from B H Howard Hortiwlmm Research Intemational East Malling England 73 Figure 6 Gra union formation following budding
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'