Propagation - Asexual - Cutting and Layering.pdf

Vegetative propagation – Cutting and Layering

1. Propagation
Vegetative propagation –Cutting and Layering
22CHOR11 - Fundamentals of Horticulture 2(1+1)
Dr. M. Kumaresan (Hort.)
Department of Horticulture
Vels Institute of Science, Technology & Advanced
Studies (VISTAS)
Pallavaram, Chennai, Tamil Nadu -600117

2. Propagation through cuttings
A cutting may be defined as any vegetative plant part, when
detached from the parent, is capable of regenerating the missing
organ or organs. According to the plant part from which a
cutting is prepared
Classified as root cuttings, stem cuttings, leaf cuttings and
leaf bud cuttings.

3. Root Cuttings
Root cuttings may be made from the true roots of any plant
species.
Their use is limited to plants with roots capable of producing
shoots or root primordia.
Root cuttings of 10 to 25 cm long are planted horizontally in soil
or moist sand and watered regularly.
The adventitious buds will sprout to produce shoots

4. Stem Cuttings
According to the nature of the wood used in making the
cuttings, stem cuttings are of four classes viz.,
1. Hard wood cuttings
2. Semi hard wood cuttings
3. Soft wood or terminal cuttings
4. Herbaceous cuttings

5. Hard wood cuttings
Most of the fruit plants are propagated by hard wood cuttings.
Cuttings are prepared during dormant, season from the wood of
the previous season growth. In certain fruit crops like fig and Olive
hard wood cuttings are prepared from two years or still older
woods. These cuttings have ample supply of stored food to nourish
developing shoots and roots. Hard wood cuttings should be about
15 to 25 cm long, with at least 2 to 3 nodes. Basal end of the
cuttings should be slanting and just below the basal node while the
top cut end should be straight and 2 to 3 cm above the last node.
These cuttings may be planted straight or slantingly in rooting
media with or without leaves keeping about 3/4th of length buried
in them. Grapes, rootstocks of roses, pear are propagated by hard
wood cuttings.

6. Semi-hard wood cuttings
Semi-hard wood cuttings is generally from evergreen species
during summer from new shoots just flush of growth has taken
place and the wood is partially matured. Leaves are retained on
this type of cuttings usually on the top side
E.g. Duranta, Hibiscus, Crotons etc.

7. Soft wood cuttings
Soft wood cuttings is also known as green woodcuttings.
These cuttings are taken from woody plants prior to lignification
when the tissues are still relatively soft. The best material of this
kind has some degree of flexibility but it is enough to break
when bent sharply. Soft wood cuttings root easier and quicker
than the other types but require more attention
E.g. Jasmine, Hibiscus etc.

8. Herbaceous cuttings
Herbaceous cuttings is made from succulent herbaceous plants
such as geranium, chrysanthemum, coleus or carnations.
This differs from soft wood cutting in that these plants will not
develop woody tissues.
These will root relatively in a shorter period under proper
conditions

9. Leaf and lead-bud cuttings
Leaf and closely, related parts are used to propagate many
common green house plants. The red begonia may be
propagated by severing some of the radial, veins or vascular
bundles of the leaf and placing it in top of a moist propagation
medium. The severed tissues are capable of regenerating both
roots and shoots, or with the subsequent production of new
plants

10. Leaf and lead-bud cuttings
A whole leaf of the common bryophyllum produces a plant from each
of its lobes
In other plants like Sansiviena, long tapering leaf is cut into sections of 5 to 8 cm.
These leaf pieces when inserted 3/4th of their length in sand, hew plants form,
after a period of time.
Leaf bud cutting consists, of leaf blade, petiole and a short-piece of
stem with the attached axiliary buds.
Axillary bud give rise to the shoot and the roots are initiated from the
basal end of the stem piece (e.g. Tea, Camellia, Rhododendron).

11. Important factors affecting the regeneration of cuttings
Food Supply: The ratio of carbohydrate to nitrogen in the stems at the time of collection of
cutting is directly related to rooting ability. High carbohydrate with low N level will aid easy
and copious rooting
Sex of the plant: Cuttings taken from the male tree root better than the female trees
(e.g. Red maple)
Age of the stock plant: Rate of formation of adventitious roots increases with increasing age of
the cuttings (e g., Apple, Pear, Eucalyptus). This is mainly due to the accumulation of rooting
inhibitors as the plants grow older. The rooting ability in such old plants can be induced by
severe pruning which tends to produce juvenile shoots
Time of year in which the Cuttings are taken: Broad leaved evergreen plants usually root most
readily if the cuttings are taken after a flush of growth has been completed and this occurs
during spring to late fall. An example is that in scented geranium the cuttings root readily
during summer and autumn months but they root poorly during winter spring months.

12. Important factors affecting the regeneration of cuttings
Presence of foliage on cuttings: Amount of leaf area left on a cutting will determine the extent
and amount of root production. The retention of a large photosynthetic leaf area will not only
reduce losses of cuttings but produce more strongly rooted cuttings in a shorter period of time
Flowering or vegetative wood: In most plants, cuttings could be made from shoots that are
either in a flowering or vegetative condition. Cuttings will root easily and more in number
when they are taken from the vegetative shoot than from flowering shoot (e.g., Jasmine)
Type of cuttings: In scented geranium, soft wood cuttings always root well than the hard wood
or semi hard wood cuttings. This kind of variation in rooting has also been observed in many
plant species
Wounding: Root production on stem cuttings can be promoted by wounding the base of the
cuttings (e.g., Magnolia and Rhododendron).

13. Environmental Conditions during Rooting
Water relation: The soft wood and herbaceous cuttings which
retain more number of leaves have to be kept without withering or
wilting by reducing its transpiration rate. This is possible by
maintaining the vapour pressure of water in the atmosphere
surrounding the leaves equal to the water vapour pressure in the
intercellular spaces within the leaf High amount of rooting in the
above kinds of cuttings is achieved in mist propagation-by
following the above principle. Such cuttings may not give adequate
rooting or may fail to root under outside condition

14. Environmental Conditions during Rooting
Temperature: For most of the cuttings, it has been established that
of day air temperature of 21 - 27°C and night temperature of about
15°C are satisfactory for rooting. Any high temperature tends to
promote bud development in advance of root development and
increase the water loss from the leaves

15. Environmental Conditions during Rooting
Light: The basic principle of a cutting responding to light may be
attributed to its effect of auxin production in plants. Cuttings
under etiolation are found to have a higher level of endogenous
auxin at the etiolated site during the period of root initiation. In
rooting leafy cuttings products of photosynthesis are more
important for root initiation growth, the synthesis of which is
dependent on light

16. Environmental Conditions during Rooting
Rooting media: The kind of rooting media can affect the type of
root system arising from the cuttings. Cuttings of some species
when, rooted in sand produce long unbranched coarse and brittle
roots but they, develop well branched roots when rooted in a
mixture of peat moss and sand. The pH of the media is also
important for rooting some species. Tea cuttings tend to produce
excess callusing (club roots) if pH of the rooting media is altered
below 4 or above 5.0.

17. Layering
Layering is the development of roots on a stem while it is still
attached to the parent plant. The layer is supported by the parent
plant until it develops its own root system. In all forms of layering,
the rooted branch is removed from the parent plant when enough
roots have formed to enable it to lead an independent existence.
The downward flow of' metabolites and hormones in phloem is
checked at the point of treatment causing accumulation of
carbohydrates in the regions where roots are produced. This is a
dependable method of inducing rooting as water and minerals are
continuously supplied to the layered shoot.

18. Advantages of Layering
It is easy to propagate new plants
Any clone which cannot be easily rooted by stem cuttings
may be made to root through layers
Desired size of plants (big or small) can be obtained by
layering

19. Disadvantages of Layering
Layering is limited to certain types of plants which produce low-lying branches.
Number of new plants which can be produced by layering from mother stock-
plant is low as compared to cuttings.
Although the operation is simple, after care of the layers is essential, this requires
daily watering to maintain a very good growth
Special platforms have to be erected and special provisions have been made for
constant watering of the layered shoots in- case where branches or shoots at high
level are to be slavered.

20. Layering
Layering is the development of roots on a stem while it is still
attached to the parent plant. The layer is supported by the parent
plant until it develops its own root system. In all forms of layering,
the rooted branch is removed from the parent plant when enough
roots have formed to enable it to lead an independent existence.
The downward flow of' metabolites and hormones in phloem is
checked at the point of treatment causing accumulation of
carbohydrates in the regions where roots are produced. This is a
dependable method of inducing rooting as water and minerals are
continuously supplied to the layered shoot.

21. Techniques in Layering
The methods of layering can be broadly divided into two
main groups viz.,
1. Ground layering
2. Air layering

22. Ground Layering
In this method the main principle is that the rooting of
layers takes place in the ground mediator in pots
containing any rooting media

23. Simple layering
It consists of bending down a shoot and burying part of
it in the soil so that the tip is above the ground level. The
buried portion is sometimes wounded by a single stroke
upwards on the underside of the shoot to be buried. The
layered branches are held firmly in position by pegs or
large stones. Roots are formed at the buried portion
where the cut is made. Low flexible branches of the
plants can be bent to the ground (e.g. Rose, Jasmine,
Guava). Sometimes a single tongue-like cut is made in
the shoots on the underside towards the growing point.
At the cut portion, a pebble is placed to avoid fusion of
tissues. This is completely covered with soil. After two
months in the cut portion roots will develop

24. Compound or Serpentine layering
This is again same like simple layering but here flexible branches may be covered with
soil in several places that they are alternately covered and exposed over their entire
length. Roots are formed usually at or in close proximity to the nodes that are covered
and new shoots develop at exposed area. When a good root system has developed at
each covered portion the new plants may be severed from the parent plants
E.g., American grapes, Clematis and Peperomia

25. Trench layering or etiolation methods
Etiolation refers to growing in darkness and in this method a branch is covered
for its entire length to produce plants from all nodes, where in roots will strike.
One year old plant is planted slantingly at an angle of 30° to 45° at a distance
of 0.9 to 1.2-m apart in the ground. Once these materials get established these
parent layers are bent over and laid flat on the bottom of a trench dug along
the row about 5 cm. (e.g., Cherry, Plum and Apple rootstocks).

26. Tip layering
In this method the apical ends or tips of current season’s shoots are
buried in the soil.
E.g blackberry and Raspberry

27. Mound layering or stool layering
It is a modification of etiolation method of layering.
The parent plant which is already established is cut
down to the ground and the resulting growth form the
stud or stool is covered up with soil at intervals.
In this method stool beds are maintained by planting
rooted layers in small trenches. During the winter
season, the dormant shoot is cut back to 5 to 10 cm
from the ground level. The soil is mounded half way up
the new shoots. If the root development, is good on the
new shoots, the rooted shoots are severed from the
parent plant and transplanted (e.g. Rootstocks of apple
and pear)

28. AIR LAYERING
•Air layering is also known as gootee or marcottage.
•In air layering roots form the aerial part of the plant where the stem has been
girdled or slit at an upward angle. Girdling consists removal of bark at the nodal
region.
•The injured portion closed with rooting medium which is maintained continuously
moist and is achieved by wrapping the moist sphagnum moss or vermiculite around
the girdled portion by polythene sheets.
•These polythene sheets permit gaseous exchange but are impervious to water.
•The roots start emerging above the girdle or on the upper portion of the cut end of
the ring.
•When the stem or shoot has produced a good root system, a first half cut is given
just below the point of rooting and within a day next half cut is given in the same
place to cut off the rooted portion.
•This separated portion is then transplanted in pots kept in the nursery for curing
•E.g., Ficus elastica, Guava and Crotons

29. AIR LAYERING