Layering propagation

Layering propagation

1. Define layering ? ⦿ Stems still attached to their parent plants may form roots where they touch a rooting medium. Severed from the parent plant, the rooted stem becomes a new plant.

2. Stems still attached to their parent plants may form roots where they touch a rooting medium. Severed from the parent plant, the rooted stem becomes a new plant. This method of vegetative propagation, called layering, promotes a high success rate because it prevents the water stress and carbohydrate shortage that plague cuttings. Some plants layer themselves naturally, but sometimes plant propagators assist the process. Layering may be enhanced by wounding one side of the stem or by bending it very sharply. The rooting medium should always provide aeration and a constant supply of moisture.

3. Dig a hole 3 to 4 inches deep. Insert the shoot tip and cover it with soil. The tip grows downward first, then bends sharply and grows upward. Roots form at the bend, and the recurved tip becomes a new plant. 5.Remove the tip layer and plant it in the early spring or late fall. 6.Examples: purple and black raspberries, trailing blackberries.

4. Bend the stem to the ground. Cover part of it with soil, leaving the last 6 to 12 inches exposed. Bend the tip into a vertical position and stake in place. The sharp bend will often induce rooting, but wounding the lower side of the branch or loosening the bark by twisting the stem may help. Examples: forsythia, honeysuckle.

5. This method works for plants with flexible stems. Bend the stem to the rooting medium as for simple layering, but alternately cover and expose stem sections. Wound the lower side of the stem sections to be covered. Examples: heart-leaf philodendron, pothos

6. Cut the plant back to 1 inch above the ground in the dormant season. Mound soil over the emerging shoots in the spring to enhance their rooting. Examples: gooseberries, apple rootstocks.

7. Air layering is used to propagate some indoor plants with thick stems, or to rejuvenate them when they become leggy. Slit the stem just below a node. Pry the slit open with a toothpick. Surround the wound with wet unmilled sphagnum moss. Wrap plastic or foil around the sphagnum moss and tie in place. When roots pervade the moss, cut the plant off below the root ball.

8. Method s of Layering Simple Layering Air Layering Compound Layering Mound Layering Trench Layering

9. Introduction Roots are formed on a stem root while still attached to the parent plant

10. C on t d. the stem or root which is rooted is called a layer the layer is removed from the plant only after rooting has taken place

11. C on t d. Layering is the process of developing new plantlets in which root formation takes place on layered port i o n of ste m be f ore they are severed from mother plant.

12. Principles of Layering Through notching or girdling,The d o w n w ar d t ra nl oca t i on o f c a rbo hy dra t e s, hormones and other organic substances is interrupted by the removal of the bark . This carbohydrates, hormones and other organic substances are accumulated in the girdled site where dormant adventitious buds regenerates and give rise to root.

13. Simple Layering a branch from the parent plant is bent to the ground covered with soil at one point terminal end remains exposed

14. Simple Layering Eg. Climbing rose, Rhododendron

15. Trench Layering parent plant is bent to the ground and covered. Shoots arise from buried buds and roots form under soil

16. Trench Layering Examples: Willows, viburnum, and dogwood

17. Serpentine Layering Similar to trench layering but the branch is alternatively covered with soil. and exposed over their entire length.

18. Serpentine Layering Eg. grapes, wisteria

19. Stool or Mound Layering parent plant is cut back to the soil level entire plant is mounded with soil forms numerous shoots and roots

20. Stool or Mound Layering Examples: apple rootstocks, quince, magnolia, etc.

21. T i p Layer i ng the tip of the stem or branches are bent down burried in the soil to the depth of 5-7.5cm.

22. T i p Layer i ng Examples: blackberries, raspberries,etc.

23. Air Layering instead, a part of the stem is girdled cut all the way around the cut is surrounded by moist sphagnum or peat moss

24. Air Layering Ancient Chinese practiced air layering process eliminates burying part of the plant in the soil

25. Air Layering Moss is wrapped with plastic to hold in place roots grow from the wound on the stem

26. Air Layering Plants that propagate well this way: Rubber Tree Persian Lime Magnolia

27. Equipment Used Pruning Knife Secateur

28. Technique of Air Layering 1.Selecting a branch: Select a healthy, nonflowering branch Pencil size 5 years old and Above branch

29. Technique of Air Layering 2 . Make two incisions in the bark, one inch apart, around the diameter Of the branch and connect with another incision

30. Technique of Air Layering 3. Remove the bark between the incisions using the connecting incision as a S t a r t i n g point

31. Technique of Air Layering 4. Applying Rooting hormone

32. Technique of Air Layering Place damp, not wet, sphagnum moss around the wound

33. Technique of Air Layering Compress and shape sphagnum moss to cover the wound - about one to two inches on either side of the wound.

34. Technique of Air Layering C o v e r w i t h p l as t i c .

35. LAYERING Definition: It is a technique of propagation in which a portion of plant is faced to the produce adventitious root while it still remains attached to mother plant.

36. Layer i ng A branch of a plant is bent over and pinned to the earth at a node When roots develop the branch is separated from the parent plant. Useful for the propagation of woody plants e.g. blackberry, gooseberry.

37. ADVANTAGES It is an effective means of propagating species that usually do not root easily by cuttings as in mango, kumquat, filberts and litchi. It is the best method of propagation of plants, which reproduce naturally by layering e.g., black berries, black raspberries, etc. It does not require precise control on water, relative humidity or temperature as is required for other methods of propagation. It is easy to perform and does not require much facility. It is possible to produce large sized plant with layering within a short time. Layering is useful for producing relatively a smaller number of plants of good size with minimum propagation facilities.

38. DISADVANTAGES It is a costlier technique in areas where labour availability is problem. It is not possible to produce large number of plants within short time. The plants produced through layering have usually small and brittle roots. In layering, the beneficial effects of rootstocks on the scion cultivar can’t be exploited. The mortality rate in layers (particularly air layers) is usually high.

39. PRINCIPLES OF LAYERING HOW ROOT FORMATION TAKES PLACE IN LAYERS? Girdling Girdling is removing the bark and phloem tissues from a stem. The stem remains alive because water and nutrients can still travel in the xylem. This treatment is used in propagation because it can halt the downward flow of auxin, so it accumulates at the site of girdling and rooting occurs in these areas even though the stem is attached to the parent plant. Water and nutrients are supplied to the layered shoots, because the stem is not cut and the xylem remain intact. This has how the root formation takes place in ground, serpentine and air- layering.

40. Etiolati o n Etiolation is development of plants or plant parts in the absence of light. The absence of light is favourable for initiation of root primordia in the stem tissue. This is how root formation takes place in round and trench layering.

41. F A C T O R S AFFE C TING THE SUC C ESS BY LAYERING Stem treatments Etiolation treatment Physiological condition of the mother plant Rejuvenation of the stock plant Treatment with growth regulators Nutrition The environmental conditions

42. METHODS OF LAYERING SIMPLE LAYERING Simple layering is perhaps the easiest and most efficient method of layering which is practiced in a great variety of woody plants without disturbing the parent plant to any extent. For making simple layers, rapidly growing shoots are first trimmed off side branches and leaves for 10-20 cm behind the tip; the shoot is then bent to ground level and covered with 5-7.5 cm of soil, leaving the tip of the shoot exposed above the soil. If the shoot comes out of the soil, it should be pegged down to the soil. The soil around the buried stem is kept reasonably moist, especially during the dry period. Sometimes a notch or a girdle or a ring is made to the stem before burying it to the soil.

43. This operation interrupts the downward movement of metabolites generated by the leaves, resulting in accumulation of carbohydrates and hormones above the notch, girdle or ring which ultimately stimulate the root formation. In most plants, rooting is complete within 4-8 weeks. The rooted layer is severed from the stock plant and kept in a pot in the nursery for about a year before planting it in the final site. E.g., lemon, black berry, grape, etc.

44. TIP L A YERING Tip layering is practiced in such plants which have got trailing type of shoots, in tip layering, growing tips of such plants are bent down and buried in the soil to a depth of 5-7.5 cm or they may be inserted in pots. The covered portion becomes etiolated and swollen, and strikes root within 2-3 weeks. The rooted layer is then severed from the mother plant and transplanted either in a permanent location or in the nursery. E.g., blackberries, raspberries, gooseberries, currant, etc.

45. SERPENTINE LAYERING OR COMPOUND LAYERING This is also very easy to perform and is practiced in plants which have long slender shoots like Jasminum or Clematis . Stems of these plants are laid in the ground and alternately covered and exposed over their entire length. Sometimes the shoots are layered into pots sunk in the ground. A slanting cut of about 5 cm long is given at a point where the shoot is to be layered sometimes ringing or girdling is also dose. Roots strike at or in close proximity to the node that is covered and new shoots arise from the buds which are not covered. E.g., strawberry.

46. TRENCH OR CONTINUOUS LAYERING In trench layering, the branch is placed in a shallow trench and is covered for its entire length, leaving only the terminal portion exposed. Trench layering has the advantage of producing many plants per branch. When the root formation is complete, the soil is removed around the layered shoot, and the rooted layers are cut off from the original stock plant. Trench layering can be adopted in the vegetative propagation of rootstocks of fruit trees that are difficult to propagate by other methods. E.g., plum, peach, etc.

47. MOUND OR STOOL LAYERING Mound (stool) layering consists of cutting back the stem of a plant to the ground during the non-growing season and covering the basal portion of the newly developing young shoots in the spring with a mound of soil. Covering with soil keeps the shoots etiolated and encourages root formation. Mounding should be done with moist soil. Sometimes to encourage root development, ringing or girdling at the base of the young shoot and application of root-promoting substances are practiced. E.g., apple root stock, pear, peach, etc.

48. Mound or stool layering: (a) the top is removed, (b) soil is heaped around the young shoots arising on the topped stump, (c) formation of roots at the bases of shoots, (d) removal of rooted layers.

49. AIR-LAYERING This method is also known as Chinese layerage, pot layerage, marcottage and gootee. Air-layering is very popular and practiced in a wide range of plants, because the method is easy to perform, does not require any specialized equipment and does not disturb the plant. Generally, long, one- to two-year-old shoots are used for air-layering. First, the leaves are removed from the base of the selected shoot, then the stem is given a notch or is girdled by removing a ring of bark about 2-3 cm wide. The girdle helps in building up high carbohydrate and hormone reserves which are necessary for easy and profuse rooting. The cut surface is sometimes treated with hormones to bring about further improvement in rooting. The ringed or girdled area is then covered with a handful of moist soil.

50. This ball of earth is again covered with moist sphagnum moss, wrapped with the polythene sheet and the two ends are then tied. The polythene film used for wrapping retains moisture and allows gaseous exchange. Air-layering is usually done either in spring or in monsoon. Depending on the species, rooting takes place within 4-8 weeks. The rooted layer is separated from the parent plant in two or three stages to reduce the stock of sudden separation. The first cut, V-shaped and going in half way through the stem, is given about 2.5 cm below the point of root emergence. The second cut which is given to deepen the first one is given a week later. A few days later the final cut is given, separating the layer from the mother plant.

51. The rooted layers are either planted in pots or in the nursery beds in a shady place until they are fully established and show renewed growth. E.g., guava, pomegranate, etc.

52. REFERENCES Plant propagation and nursery management by R. R. Sharma and Manish Srivastav. Propagation of tropical and subtropical horticultural crops by T. K. Bose, S. K. Mitra, M. K. Sadhu, P. Das, D. Sanyal. Fundamentals of horticulture by Jitendra Singh. Basic concepts of fruit science by Neeraj Pratap Singh. www.leavingcertbiology.net. www.online-sciences.com. www.majordifferences.com.

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