Grafting is the act of joining two plants together. The upper part of the graft (the scion) becomes the top of the plant or tree, the lower portion (the understock or rootstock) becomes the root system or the bottom part of the trunk. Although grafting usually refers to joining only two plants, it may be a combination of several. A third plant added between two others becomes the trunk or a portion of it. This is called an interstem.
Budding is a method of grafting in which the
scion (upper portion of the graft) is a single bud rather than a piece of stem
or twig. Budding is a form of asexual reproduction in which a new organism develops
from an outgrowth or bud on another one. The new organism remains attached as
it grows, separating from the parent organism only when it is mature, leaving
behind scar tissue. Since the reproduction is asexual, the newly created
organism is a clone and is genetically identical to the parent organism.
Generally, deciduous fruit and shade trees are well suited to budding. PRINCIPLES OF GRAFTING AND BUDDING
Grafting is a
historic method of propagating fruit, nut and ornamental trees. Its use by the
Chinese has been documented as early as 1560 BC. The technique was discussed in
detail by historic writers including Aristotle and Theophrastus and it became
very popular in
Europe during the Rnaissance (1350 to 1600). Grafting is still important today
and is the basis for commercial production of fruit, nut and many ornamental
trees.
- Preparing the Rootstock
Rootstock can be grown in the field where it will be budded,
or dormant liners can be transplanted into the field and then allowed to grow
under moderate fertility until they reach the desired 3/16- to 7/16-inch
caliper. Since budding is generally done less than 4 inches above the soil
surface, leaves and side branches must be removed from this portion of the
rootstock to create a clean, smooth working area. To avoid quickly dulling the knife,
remove any soil from the rootstock where the cut will be made just before
actual budding takes place. The stem can be cleaned by brushing or rubbing it
gently by hand or with a piece of soft cloth.
- Preparing the Budwood
Collect scion or budwood early in the day while temperatures
are cool and the plants are still fully turgid. The best vegetative buds
usually come from the inside canopy of the tree on the current season's growth.
Mature buds are most desirable; discard terminal and younger buds because they
are often not mature. To keep budwood from drying out, getting hot, or freezing
(depending on the season), place it into plastic bags or wrap it in moist
burlap as it is collected. Then move to a shaded or sheltered area to prepare
the buds. Place budwood of only one variety in each labeled bag.
Budsticks are usually prepared in a cool, shaded area. Remove
the leaves but keep the petioles (leaf stem) intact to serve as handles when
inserting a bud into the rootstock. Then cut the sticks to a convenient length,
leaving three to six buds per stick. Budsticks that will not be used
immediately should be bundled, labeled, and stored in moisture-retaining
containers such as plastic bags or waxed cardboard boxes and kept cool (32o
to 45oF). The longer budwood is stored, the less likely it is to
"take." Generally, budwood stored for more than a few days should be
discarded.
When budwood is taken to the field, equal precautions against
drying should be taken. Storing budwood in a picnic cooler with ice will help
keep it cool and moist. Individual bundles of scions carried by budders are
often wrapped in moist burlap or kept in dark (not clear) plastic.
FACTORS THAT
INFLUENCE GRAFTING SUCCESS:-
- Plant
- Temperature
- Moisture
- Growth activity of rootstock
- Polarity
- Craftsmanship
- Pests and diseases
- Compatibility