Vegetatively propagated crops are bred by intentionally crossing of closely or distantly related individual to produce new crop varieties or lines with desirable traits. Breeding of vegetative crops have successfully improved quality, yield, tolerance of crops to environmental pressure. Breeding helps in producing crops that are resistant to viruses, fungi and bacteria and helps in longer storage period for the harvested crop.

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Plant Breeding Methods of
Vegetatively Propagated Crops
Prepared By
Roksana Aftab Ruhi
Department of Agriculture
Noakhali Science and Technology University
Noakhali, Chittagong, Bangladesh.

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CONTENTS
Topics
❖Introduction
❖Plant Breeding
❖Plant Breeding Methods
❖Vegetative Propagation
❖Types of Vegetative Propagation
❖Characteristics of Vegetative Propagated Crops
❖Breeding Method in Vegetative Propagated Crops
❖Mutation Breeding Method in Vegetative Propagated
Crops
❖Procedure in Mutation Breeding Method
❖Achievements and Limitations of Mutation Breeding
❖Hybridization Breeding Method in Vegetative
Propagated Crops
❖Procedure in Hybridization Breeding Method
❖Achievements of Problems in Breeding Methods of
Vegetative Propagated Crops
❖Conclusion
❖Figures
❖References

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Introduction
Plant breeding is the genetic improvement of plants in order to create desired
plant types that are better suited for cultivation, give quality yields, tolerate
environment pressure and are disease resistant. Vegetative propagated crops
which are the most horticultural crops used for food and cash crops are bred to
improve human and economic live of a nation. Most of our major crops are
derived from the domesticated varieties. Due to advancement in genetics,
molecular biology and tissue culture plant breeding is being carried out by using
molecular genetics tools.
Vegetatively propagated crops are bred by intentionally crossing of closely or
distantly related individual to produce new crop varieties or lines with desirable
traits. Breeding of vegetative crops have successfully improved quality, yield,
tolerance of crops to environmental pressure. Breeding helps in producing crops
that are resistant to viruses, fungi and bacteria and helps in longer storage period
for the harvested crop.
Plant Breeding
Plant breeding is an applied branch of Botany, which deals with improvement of
agricultural crops. This branch of agricultural science has contributed maximum
to the increase in food production all over the world and therefore, now a day it
assuming ever increasing importance in field of agriculture in every country.
● Other Published Definitions
"Plant Breeding is the art and science of the genetic improvement of plants." -
Fehr,Principles of Cultivar Development: Theory and Technique, 1987

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"Plant Breeding is the art and science of changing the traits of plants in order to
product desired characteristics." - Sleper and Poehlman, Breeding Field Crops,
1995
"Plant Breeding is the genetic improvement of plants for human benefit." -
Bernardo, Breeding for Quantitative Traits in Plants, 2010
Frankel, 1958 defined “Plant breeding as the genetic adjustment of plants to the
service man.’
Plant Breeding Methods
The vast diversity of breeding methods can be simplfied into three categories:
A. Plant Breeding Based on Observed Variation
✓ Plant Domestication
✓ Pure Line Selection and Mass Selection
✓ Intuitive Farmer Selection
B. Plant Breeding Based on Controlled Mating
✓ Pedigree Breeding
✓ Ideotype Breeding
✓ Population Breeding
✓ Hybrid Breeding
C. Plant Breeding Based on Monitored Recombination
✓ Mapping Genes of Interes
✓ Marker-Assisted Selectio
✓ Genomic Selection

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Vegetative Propagation
Plant propagation is the method of increasing the number of plants of
a particular cultivar or species. Vegetative propagation also known as
asexual or clonel vegetation is a plant propagation method that produce
new plants from vegetative parts (leaves, stems and roots) of the
original plant. It is a process by which new organisms arise without
production of seeds or spores. It can occur naturally or be induced by
horticulturists
Types of Vegetative Propagation
● Natural vegetative propagation.
● Artificial vegetative propagation.
· Natural Vegetative Propagation: Natural vegetative
propagation occurs when an axillary bud grows into a lateral shoot
and forms its own roots (adventitious root). Plant structures involved
in natural vegetative propagation include Bulbs, Rhizomes, Stolons
and tubers.
Bulbs: They form lateral buds from the base of the mother bulb
producing smaller bulbs or bulbels in coming years e.g.Onion.
Rhizomes: They are root like stems that grows horizontally under the
round. Examples root ginger.
Stolons: They are also known as runners. They are horizontal stems
that grows above the ground e.g. strawberries.

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Tubers: They are swollen part of an underground stem that store
food so a plant can lie dormant. E.g. Potatoes.
Artificial Vegetative Propagation : These are induced
form of vegetative propagation. It involves taking a piece of one parent
plant and causing it to regenerate itself into a new plant. They methods
are commonly: cuttings, grafting and budding, tissue culture and
vegetative apoximixis.
Cutting: A cutting is a piece from a plant that has been cut off from a
mother plant and then caused to grow in a whole plant.
Tissue culture: In these method, tiny fragments of plants are treated
with plant hormones in a sterile growing medium.
Grafting and budding: This method involves joining a stem piece or
a single bud onto the stem of a plant that has roots. The stem piece is
called the scion and the plant with root is called a root stock.
Characteristics of Vegetative Propagated
Crops:
1.Most of these plants are perennial and annual. E.g Sugarcane,
potato, sweet potato.
2. Many of them shows reduced flowering and seed set and
many varieties do not flower at all.
3. They are invariably cross-pollinated.

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4. They are nightly heterozygous and show severe inbreeding
depression.
5. Many species are interspecific hybrid. E.g Banana, sugarcane.
6. Many species shows wider adaptation.
7. These crop consist of a large number of clones i.e. progeny
derived from single plat through asexual reproduction.
Methods Involved in The Breeding Of
Vegetative Propagated Crops
● Domestication: This is not majorly involved in vegetative
propagated crops breeding, but is involved in the process. It is
the process of cultivating vegetative crops and keeping them
under human care and management.
● Collection of germplasm : Germ plasm is the sum total of all
genes present in a crop. The entire collection of vegetative
propagated crops having all the diverse alleles for all genes in
a given crop is known as Germ plasm collection.
● The germplasm of any crop species consist of the following
types of materials:
1) Cultivated improved varieties
2) All the wild species related to the crop species
3) Improved varieties that are no more cultivated
4) Old local varieties.

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The collection of germ plasm from different sources id an
essential first step in any breeding work, and germ plasm is
usually stored at a low temperature, and it is cone within country
or from other countries.
● Evaluation and selection of parents: The parents are
evaluated to identify plants with desirable combination of
characters.
● Plant Evaluation: This is the process of introducing plants of
germ plasms either from a foreign country or introducing
plants or germ plasm from one region to other region of the
same country. After plant introduction, an adaptation period
is followed. Plant introduction is done for the purpose of
genetically improvement of economical crops and also for
studying the origin, distribution, classification and evolution
of plants.
5) Hybridization: This is the mating or crossing of two plants or
lines of dissimilar genotype. The objective of hybridization is to
create genetic variation. When two dissimilar genotypical palnts
are crossed, the genes from both the parents are brought together
in F1 generation. Segregation and recombination produce many
new gene combination in F2 and further generation.
The aim of hybridization may be transfer of one or
few qualitative characters, improvement of one or more
quantitative traits or use of the F1 as a hybrid variety.

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6) Mutation Breeding : Mutation are sudden unpredictable
heritable changes
without any Intermediate stage in characteristics of organism. It is the
permanent and
relatively rare
Change in the nucleotide sequence of the concerned gene or
chromosome structure and
chromosome number.
7) Polyploidy Breeding: Polyploidy breeding in vegetative
propagated crops involves the number or sets of chromosome or
genomes in a cell of an organism. Vegetative propagated crops having
polyploidy conditions are potato, sugar cane, banana, tobacco, e.t.c
Mutation Breeding Method in Vegetative
Propagated Crops
Mutation breeding is hugely successful. The wide use of mutation
induction for crop improvement is documented in the FAO/IAEA
Mutant Variety Database, which includes more than 3200 officially
released mutant varieties from 214 different plant species in more than
60 countries throughout the world.

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Definition : The utilisations of induced mutation in crop
improvement is called mutation breeding .It is the sudden heritable
change in an organism.
● Mutations can be induced by some physical and chemical agents,
called mutagens. Mutagens greatly enhance the frequency of
mutations. Mutagenic action of X-ray was first discovered by
Muller in 1927, and that of nitrogen mustards by Averbach and
Robson in 1946.
● Based on their effect on survival, mutations are classified into
four groups: lethal,sub-lethal, sub-vital, and vital. Mutation
breeding utilizes vital mutations only.
A. Physical Mutagens:
➢ Ionizing Radiation
➢ Non-ionizing Radiation
B. Chemical Mutagens:
➢ MMS(Methyl Methane Salphonate)
➢ 5 Bromo Uracil
➢ Nitrous Acid
Procedure in Mutation Breeding Method
Treating a biological material with a mutagen in order to induce
mutation. Irradiation :- Exposure of biological material to one of the

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radiation(X-rays, gamma rays etc.). When mutations are induced for
crop improvement, the entire operation of the induction & isolation etc.
of mutants is termed as mutation breeding.
Selection of the variety for mutagen treatment :
Selection of the variety for mutagen treatment Generally the variety
selected for mutagenesis should be the best variety available in the
crop. Note: In certain situations, it may be desirable to isolate in
varieties other than the best one, ex. Dwarf & semi dwarf mutants
would have to be isolated from tall varieties in cereal crops (wheat, rice
etc.)
Part of the plant to be treated :
Part of the plant to be treated Seeds, pollen grains, buds/cuttings or
complete plant can be used for mutagenesis. It depends on whether the
crop is sexually or asexually propagated & on the mutagen to be used.
Sexually propagated crops : Seeds are commonly used because seed
can tolerate extreme environmental conditions.
● Pollen grains are also infrequently used because They are
difficult to collect in large quantities. Hand pollination(with
treated pollens) is rather difficult. Survival percentage of pollens
is relatively low.
● Note- Pollen grains are the only plant part which can be treated
with ultra violet rays.

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Dose of the mutagen :
Dose of the mutagen Clonal crops: Buds/cuttings are used for
mutagenesis. The usefulness of a mutagen and its efficiency depends
on the mutagenic agent employed as well as on specific characteristics
of the biological system to be treated. An optimum dose is the one
which produce the maximum frequency of mutation causes minimum
killing. LD50 dose should be optimum.
Giving mutagen treatment :
Giving mutagen treatment The plant part is exposed to the desired
mutagen dose. In irradiation the plant parts are immediately planted to
raise M1 plants from them. In case of chemical mutagens seeds are
usually soaked for few hours to initiate metabolic activities. Then they
are washed under running tap water. After this they are planted in the
field to raise M1 generation.
Handling of mutagenic population :
Handling of mutagenic population Treatment of seeds & vegetative
propagules commonly produce chimeras. Shoot tip meristem has three
layers :- L1 :- Give rise to epidermis. L2 :- Part of leaf mesophyll &
gametes. L3 :- Yield the rest of plant. Periclinal chimera :- When the
whole of L1 , L2 or L3 layer is affected. Sectorial chimera :- When
only a part of L1 , L2 or L3 layer is affected .

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Achievements and Limitations of Mutation
Breeding
1. A number of crop varieties have been developed through
mutation breeding.
A brief list given below=
Cereals:350
Legumes:62
Fruits:40
Ornamental :462
2. The first commercial success with induced mutations was reported
in 1934 with the release of a new tobacco cultivar ‘Chlorina’ through
X-ray irradiation.
3. Many varieties of barley contain artificially mutated genes which
contribute to reduction in height, increase in yield, insensitivity to day
length and resistance to mildew diseases. Sharbati Sonara and Pusa
Lerma are two amber grain colour mutants of wheat produced from the
red grained Sonara 64 and Lerma Rojo 64A, respectively. A mutant
gene that induces semi-dwarfing in rice has been produced by X-ray
treatment.
Induced mutations have also become recently important in developing
parents useful in hybridization programmes. Forty-five rice cultivars
have been developed by the year 1982, either by direct radiation or by
crossing with induced mutants.

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4.Crop plants are propagated vegetatively even though they can bear
seed. Potato, tapioca and sugarcane are classical examples of such
crops.
In these, genetic improvement is carried out using sexual reproduction
but the maintenance of the improved varieties is by cloning. For
examples, potatoes are multiplied by tubers, apples by cuttings, and
strawberries by runners.
5. Spontaneous mutations in somatic cells of a vegetatively propagated
plant are commonly referred to as SPORTS. Such desirable sports
occurring in well-adapted, asexually reproducing plants may result in
quick improvements such as the colour sports in many apple varieties
and superior shrub types in coffee plants.
6. The characters improved through mutation breeding include
flowering time, flower shape, fruit shape, changes in oil content, and
protein quality.
● Some of the important limitations of the use of
mutation breeding for vegetative propagating
crop improvement are:
(i) Most induced mutations are undesirable and have no value to the
breeder. Many induced mutations are lethal.

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(ii) The mutation rate is extremely low and a very large number of
plants must be screened to identify the few individuals that may have
desirable mutations.
(iii) The stability of a mutant must be thoroughly tested as some
mutants have a tendency to revert.
(iv) Most induced mutations are recessive; these have to be in double
dose to be expressed phenotypically.
(v) There may be problem in registration of mutant variety of many
plants
Hybridization Breeding Method in Vegetative
Propagated Crops
Definition : Hybridization may be defined as “The mating or
crossing of two plants or lines of dissimilar genotype.” The chief
objective of hybridization is to create genetic variation. When two
genotypically different plants are crossed, the genes from both the
parents are brought together in F1 generation.
Types :
Two types:
(i) Interspecific and (ii) Inter-generic.
● Interspecific Hybridization: Here the plants of two different
species belonging to the same genus are crossed together. It is

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also known as intra-generic hybridisation (within the same
genus). All the disease, insect, drought and frost resistant
varieties in wheat, tomato, sugarcane, etc., have been evolved by
this method.
Two species of sugarcane are cultivated in India-Saccharum
officianarum in Central and South India, while S. barberi is grown in
northern India. Both these species are susceptible to red rot, lodging
and drought. A wild species of sugarcane, S. spontaneum has genes for
resistance to diseases to which cultivated species are susceptible.
Therefore, to introduce the genes for resistance to diseases, both of the
cultivated species were crossed with the wild species S. spontaneum
individually and thus high-yielding, disease resistant canes have been
evolved.
(50% characters of cultivated species, 50% characters of wild species)
It was found that the hybrid shows some bad features of wild species,
like no sugar content. So bad characters have to be got rid off. For this,
back crossing is carried out. In back crossing, hybrid is crossed with
the cultivated species, which has the characters tor sugar content.

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So by continued backcrossing, canes with high sugar content have been
obtained.
● Inter-generic Hybridization: Crosses made between plants
belonging to two different genera constitute inter-generic
hybridisation
.
Cross between Sugarcane and Sorghum:
Sugarcane takes about 9 months to ripe and so no other crop can be
grown. Sorghum, on the other hand, is a short duration crop (3 to 4
months). So early maturing sugarcane varieties have been evolved by
crossing with sorghum.
Procedures in Hybridization Breeding Method
Improved clones of asexually propagating plants are selected and
allowed to grow under conditions, which favour flowering and seed
setting. Desirable clones are crossed together and the hybrids are
multiplied by cloning. Each F1 plant is a potential source for a new
clone. This procedure has been used for developing many improved
varieties of sugarcane, potato etc. (Fig. 14).

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Achievements of Problems in Breeding
Methods of Vegetative Propagated Crops
Clonal Selection:
In India clonal selection has been successfully used for developing
varieties in potato, sugarcane, banana, citrus, etc.
Potato: Kufri red, Kufri safed.

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Mango: Neelam, Ko-11, Ko-22.
Hybridization:
A large number of varieties of clonal crops have been developed
through hybridization.
Potato: Kufri Alankar, Kufri Kuber, Kufri Sindhuri, Kufri Kundan
Sugarcane: Co-1148, Co-1158, Co-975, Co-541, etc.

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Conclusion
Many agricultural crops of economic importance are vegetatively
propagated. This work was done to elaborate more on vegetatively
propagated crops, importance and developing new cultivars of
vegetative propagated crops. Vegetative propagation aids to fix
favorable combinations of important traits, very specific chemical
compositions, superior genetic variance interactions and high levels of
heterozygosity.
Breeding vegetative propagated crops involve few genetic crossing and
genetic combination by sexual reproduction. Vegetatively propagated
crops are best suited for maintaining hybrid vigour because once a
desired hybrid has been produced; there are fewer chances of losing it.
Breeding by mutation enables to get improved characters in plant like
tolerance to environment pressure, plant shape, changes in oil content,
disease resistant in plant and protein quality.

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References
● http://agriinfo.in/default.aspx?page=topic&superid=3&topicid=
1792
● http://eliciousuzo.blogspot.com/2016/09/breeding-method-for-
vegetatively.html
● National Association of plant breeding (US),
https://www.plantbreeding.org/content/what-is-plant-breeding
● http://www-naweb.iaea.org/nafa/pbg/mutation-breeding.html
● http://www.easybiologyclass.com/mutation-breeding-technique-
for-the-improvement-of-crop-plants-with-ppt/
● http://www.biologydiscussion.com/plant-breeding/steps-
involved-in-the-plant-breeding-process-4-steps/15641
● http://pubs.acs.org/doi/pdf/10.1021/jf305531j
● https://www.bats.ch/bats/publikationen/1995-1_TA/2-
methods.php
● http://www.authorstream.com/Presentation/chhabra61-438993-
mutation-breeding-crop-improvement/
● http://www.biologydiscussion.com/crops/improvement/hybridiz
ation-method-of-crop-improvement/17701

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