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Layering is the developing of roots on a stem while it is still attached to the parent plant. The rooted stem is then detached or become a new plant growing on its own roots. A layered stem is known as a layer.Layering includes several forms of ground and aerial layering. When rooting is encouraged
on the aerial part of a part of a plant after wounding it is known as air layering or gooty or marcottage. When branches running parallel to ground are utilized, it is known as ground layering, The root formation during layering on a stem is stimulated by various stem treatments like ringing, notching etc, which causes an interruption in the downward translocation of carbohydrates and other growth factors from leaves and growing shoot tips.
However, the root formation in layered stems, completely depends upon continuous moisture supply, good aeration and moderate temperature around the rooting zone.
Some times synthetic growth regulators like IBA, IAA etc, are also treated to layered stem to induce better rooting, as the auxins in layered stem is an important factor for rooting.
Advantages:
i. It is an easy method and does not require much care and arrangement like cutting.
ii. The mother plant supplies nutrient and other metabolites as it remains attached while rooting.
iii. By using a large branch a much larger plant can be obtained in the first instance.
iv. Some plants that cannot be satisfactorily started from cuttings can be propagated by layering.
Disadvantages:
ii. The mother plant supplies nutrient and other metabolites as it remains attached while rooting.
iii. By using a large branch a much larger plant can be obtained in the first instance.
iv. Some plants that cannot be satisfactorily started from cuttings can be propagated by layering.
Disadvantages:
i. It is a costlier method.
ii. It is a slow process
iii. Limited number of plants can be propagated
iv.Layered plants are generally shallow rooted
v.Interference with cultivation
vi.Require more individual attention
vii.The beneficial effect of root stock cannot be exploited.
ii. It is a slow process
iii. Limited number of plants can be propagated
iv.Layered plants are generally shallow rooted
v.Interference with cultivation
vi.Require more individual attention
vii.The beneficial effect of root stock cannot be exploited.
Classification of layering:
I. Ground layering
1)Tip layering
2)Simple layering
3)Trench layering
4)Mound layering or stool layering
5)Compound or serpentine layering
II.Air layering. (Gootee or Marcottage).
1)Tip layering
2)Simple layering
3)Trench layering
4)Mound layering or stool layering
5)Compound or serpentine layering
II.Air layering. (Gootee or Marcottage).
Tip layering : It is generally followed in plants which have trailing type of shoots. It is quite similar to simple layering.
Procedure: Dig a hole 3 to 4 inches deep. Insert the tip of a current season‘s shoot and cover it with soil. The tip grows downward first, then bends sharply and grows upward. Roots form at the bend. The re-curved tip becomes a new plant. Remove the tip layer and plant it in late fall or early spring. Examples of plants propagated by tip layering include purple and black raspberries, and trailing blackberries Simple layering
Simple Layering: In this method, a branch is bent to the ground and some portion of it is covered by soil leaving the terminal end of the branch exposed.Root initiation takes place at the bent and buried portion. After allowing sufficient time for root formation, the rooted stem is separated from the mother plant. Eg. Bougainvillea, Jasmine, Rangoon creeper. Procedure: Select a healthy, flexible and sufficiently long (50 to 60cm) branch towards the base of the plant. The selected branch should be closer to the ground. At a distance of about 15 to 30cm back from the tip give a sharp, slanting inward and upward cut 1.5 to 2.5cm below a node and insert a small wood splinter. Bend the shoot gently to the ground so that the treated part can conveniently be inserted into the soil. Cover the treated region with soil. Peg down the shoot or keep a stone of brick on the covered soil to keep the layered shoot in place. Drive a vertical stake into the soil by the side of the layered branch and tie the terminal portion of the branch to keep it upright. Water the layered portion regularly so as to keep it moist all through till root initiation take place. After sufficient root formation separate the layer by cutting just below the rooted zone.
Simple Layering: In this method, a branch is bent to the ground and some portion of it is covered by soil leaving the terminal end of the branch exposed.Root initiation takes place at the bent and buried portion. After allowing sufficient time for root formation, the rooted stem is separated from the mother plant. Eg. Bougainvillea, Jasmine, Rangoon creeper. Procedure: Select a healthy, flexible and sufficiently long (50 to 60cm) branch towards the base of the plant. The selected branch should be closer to the ground. At a distance of about 15 to 30cm back from the tip give a sharp, slanting inward and upward cut 1.5 to 2.5cm below a node and insert a small wood splinter. Bend the shoot gently to the ground so that the treated part can conveniently be inserted into the soil. Cover the treated region with soil. Peg down the shoot or keep a stone of brick on the covered soil to keep the layered shoot in place. Drive a vertical stake into the soil by the side of the layered branch and tie the terminal portion of the branch to keep it upright. Water the layered portion regularly so as to keep it moist all through till root initiation take place. After sufficient root formation separate the layer by cutting just below the rooted zone.
Compound or serpentine layering : Compound layering is essentially the same as the simple layering except that the branch is alternatively covered and exposed along its length. The branch for compound layering must be long and flexible so that it can be layered at different places along its length. Eg. Bougainvillea, Jasmine, Rangoon creeper.
Procedure: Select a healthy, flexible and sufficiently long (100 to 250 cm) basal branch that is close to the ground. Give a sharp slanting, inward and upward cut 1.5 to 2.5 cm below a node at 30cm interval starting from the tip leaving 3 to 3 buds in between two such cuts. Bend the shoot gently to the ground, and insert and cover the cut portions with the soil exposing the uncut portions. The remaining steps are same as in simple layering.
Mound or stool layering : Mound (stool) Layering: In this method, a plant is cut back to the ground level during the dormant season and soil is heaped around the base of the newly developing shoots. After slowing sufficient time for root initiation, individual rooted layers are separated from the mother plant and panted. Eg. Apple roots tocks, Guava, Litchi, Quince, Procedure: Select the plant to be mound layered or plant a rooted layer in a trench and allow it to grow for a year. Cut back the plant to 2.5 cm from the ground level just before growth begins. Allow the new shoots to develop. When these shoots have grown 7 to 15 cm tall, girdle them at the base and treat the girdle portion with the recommended growth regulator and draw up the loose soil round each shoot to half its height. When these shoots have are 20 to 25 cm tall add soil again to half their height. Add soil again when the shoots grow to a height of about 35 to 45 cm. Water the heaped soil regularly and allow sufficient time for the initiation of roots. A depression can be made in the centre of the heap to hold water. After sufficient root formation, remove the heaped soil and cut the rooted shoots individually to their base. Transplant the rooted shots in pots or suitable containers. Trench Layering Trench Layering: Trench layering consists of growing a plant or a branch of a plant in a horizontal position in the base of a trench and filling in soil a round the new shoots as they develop, so that the shoot bases are etiolated. Roots develop from the base of these new shoots. Etiolated roots develop from the base of these new shoots.
Mound or stool layering : Mound (stool) Layering: In this method, a plant is cut back to the ground level during the dormant season and soil is heaped around the base of the newly developing shoots. After slowing sufficient time for root initiation, individual rooted layers are separated from the mother plant and panted. Eg. Apple roots tocks, Guava, Litchi, Quince, Procedure: Select the plant to be mound layered or plant a rooted layer in a trench and allow it to grow for a year. Cut back the plant to 2.5 cm from the ground level just before growth begins. Allow the new shoots to develop. When these shoots have grown 7 to 15 cm tall, girdle them at the base and treat the girdle portion with the recommended growth regulator and draw up the loose soil round each shoot to half its height. When these shoots have are 20 to 25 cm tall add soil again to half their height. Add soil again when the shoots grow to a height of about 35 to 45 cm. Water the heaped soil regularly and allow sufficient time for the initiation of roots. A depression can be made in the centre of the heap to hold water. After sufficient root formation, remove the heaped soil and cut the rooted shoots individually to their base. Transplant the rooted shots in pots or suitable containers. Trench Layering Trench Layering: Trench layering consists of growing a plant or a branch of a plant in a horizontal position in the base of a trench and filling in soil a round the new shoots as they develop, so that the shoot bases are etiolated. Roots develop from the base of these new shoots. Etiolated roots develop from the base of these new shoots.
Trench layering : It is used primarily for woody species difficult to propagate by mound layering. Eg. Apple rootstocks, Litchi, Quince.
Procedure: Dig small trenches of about 25-30cm deep and in about 1 m wide rows. Plant rooted layers or one year old nursery – budded or grafted plants in the trenches in rows at an angle of 30O to 45 Oand 50 to 10cm apart within the row.The rows should be1.2 to 1.5 m apart. Just before growth begins, lay the plant or a branch flat on the bottom of the trench. Plants must be kept completely flat with wooden pegs or wire fasteners. Cut back the shoots slightly and remove the weak branches. Add roots medium (sand or sawdust or peat moss) or their mixture at intervals to produce etiolating on 5 to 10 cm of the base of the developing shoots. Apply first 2.5 to 5cm layer before buds swell and repeat as shoots emerge and expand. At the end of the season, remove the medium and cut off the rooted shoots close to the parent plant. Transplant the rooted shoots in pots or suitable containers.
II. Air Layering: In air layering roots form on an aerial shoot. The rooting medium is tied to the shoot for getting root initiation. Sphagnum moss is the best rooting medium for air layering as it holds large quantities of water till root initiation and through the root initiation and through the root development. Eg. Crotons, ficus, fig, Guava, Phalsa, Pomegranate.
Procedure: Select a healthy branch of previous season‘s growth. At a point 15 to 30 cm back from the tip of the shoot make a girdle just below a node by completely removing a strip of bark 2 to 3.5 cm wide all around the shot. Scrape the exposed surface lightly to remove traces a phloem or cambium to retard healing. In difficult-toroot species treat the girdled portion with the recommended growth regulator to induce better rooting. Cover the girdled portion with moist propagating medium. Sphagnum mass, saw dust, vermiculite. Tie the medium around the girdled portion using a polyethylene sheet. Tying should be perfect so that no water can enter the treated part. After observing the fully developed roots through the transparent polyethylene sheet, separate the root zone and transplant the layer appropriately.
Procedure: Dig small trenches of about 25-30cm deep and in about 1 m wide rows. Plant rooted layers or one year old nursery – budded or grafted plants in the trenches in rows at an angle of 30O to 45 Oand 50 to 10cm apart within the row.The rows should be1.2 to 1.5 m apart. Just before growth begins, lay the plant or a branch flat on the bottom of the trench. Plants must be kept completely flat with wooden pegs or wire fasteners. Cut back the shoots slightly and remove the weak branches. Add roots medium (sand or sawdust or peat moss) or their mixture at intervals to produce etiolating on 5 to 10 cm of the base of the developing shoots. Apply first 2.5 to 5cm layer before buds swell and repeat as shoots emerge and expand. At the end of the season, remove the medium and cut off the rooted shoots close to the parent plant. Transplant the rooted shoots in pots or suitable containers.
II. Air Layering: In air layering roots form on an aerial shoot. The rooting medium is tied to the shoot for getting root initiation. Sphagnum moss is the best rooting medium for air layering as it holds large quantities of water till root initiation and through the root initiation and through the root development. Eg. Crotons, ficus, fig, Guava, Phalsa, Pomegranate.
Procedure: Select a healthy branch of previous season‘s growth. At a point 15 to 30 cm back from the tip of the shoot make a girdle just below a node by completely removing a strip of bark 2 to 3.5 cm wide all around the shot. Scrape the exposed surface lightly to remove traces a phloem or cambium to retard healing. In difficult-toroot species treat the girdled portion with the recommended growth regulator to induce better rooting. Cover the girdled portion with moist propagating medium. Sphagnum mass, saw dust, vermiculite. Tie the medium around the girdled portion using a polyethylene sheet. Tying should be perfect so that no water can enter the treated part. After observing the fully developed roots through the transparent polyethylene sheet, separate the root zone and transplant the layer appropriately.