Environment and Genetic Control

Question 1

Budding Rubbers

Answer 1

• must be tied with a half-hitch or slip knot
• which is done at the final turn of the tape by slipping it under the previous turn
• they do not deteriorate in full sunlight and must be removed later to prevent girdling the plant

Question 2

Callus Bridge

Answer 2

• the graft interface
• is made up of a prolification of callus cells

Question 3

Delayed Graft Incompatibility

Answer 3

• the process wher ethe graft will unite initially with apparent success, but fails over time

Question 4

Graft Union Formation

Answer 4

• initially formed by rapidly dividing callus cells, originating from the scion and rootstock, which later differentiate to form the vascular cambium (a lateral meristem) and the associated vascular system
• the development of a compatible graft is typically comprised of several major events:

1. Adhesion of the rootstock and scion
2. proliferation of callus cells at the graft interface or callus bridge
3. vascular differentiation across the graft interface

• there are 5 stages to graft union formation:

1. lining up the vascular cambium
2. a wound response
3. callus bridge formation
4. xylem and phloem differentiation into a new vascular cambium
5. secondary xylem and phloem develop across the graft

Question 5

Grafting Case

Answer 5

• enclosed cases that maintain high humidity around the graft union
• sometimes glass coverings for individual grafts

Question 6

Grafting Clips

Answer 6

• .plastic clips that are used in manual and machine splice grafting of vegetable crops

Question 7

Grafting Wax

Answer 7

• wax that seals over the graft union, thereby preventing the loss of moisture and death of the tender, exposed cells of the cut surfaces of the scion and rootstock
• an ideal graft wax should adhere well to the plant surfaces, not be washed off by rains, not be so brittle as to crack and chip during cold weather or so soft that it will melt and run off during hot days, but still be pliable enough to allow for swelling of the scion and growth enlargement of the rootstock without cracking

Question 8

Grow Straights

Answer 8

• metal shoot guide clips that are used to obtain upright scion growth as the bud elongates
• since they are attached to the rootstock or inserted into the soil, grow straights give some mechanical support to the elongated scion shoot

Question 9

Hot Pipe Callusing System

Answer 9

• with some difficult to graft species, a warm temperature around the graft can be beneficial
• the hot pipe callusing system warms the graft union to about 80 F. but keeps the roots and buds on the scion cool (about 45 F) to prevent their premature growth
• the graft union is kept warm by a PVC pipe that contains a hot wire or re-circulating hot water system
• the entire system is insulated around the graft and the scion and roots are kept cool
• hot pipe callusing is preformed in the late winter or early spring

Question 10

Non-Translocatable (Localized) Graft Incompatibility

Answer 10

• a type of localized incompability where contact cells from the two partners fail to recognize each other and do not initiate callus formation

Question 11

Nursery Tape

Answer 11

• adhesive tape is similar to surgical adhesive tape but lighter in weight and not sterilized
• the adhesive tape is useful for tying and sealing whip grafts
• when this type of wrapping is covered with soil, it usually rots and breaks before any girdling damage can occur

Question 12

Parafilm

Answer 12

• used to cover graft or budding area in order to retain the natural moisture of the tissues
• a self-sealing tying material
• has been used with successful results to wrap graft unions rapidly and for ship-budding roses
• this material is waterproof, flexible, stretchable, thermoplastic film with a paper backing
• the film is removed from the paper, wrapped around the graft union, and pressed into place by hand

Question 13

Pathogen-induced Graft Incompatibility

Answer 13

• viruses and phytoplasma (mycroplasma-like organisms)
• cause pathogen-induced incompatibility

Question 14

Polyethylene Tape

Answer 14

• used to cover graft or budding area in order to retain the natureal moisture of the tissues
• .5 to 1.3 cm wide and slightly elastic, allowing for a more secure wrap

Question 15

Translocatable Graft Incompatibility

Answer 15

• includes certain graft/rootstock combinations in which the insertion of a mutually compatible interstock does not over come incompability
• some biochemical influence moves across the interstock and causes phloen degeneration

Question 16

Waxed String

Answer 16

• string or twine that adheres to itself and to the plant parts without tying a slip knot
• it should be removed following healing of the graft union