Breeding techniques in self pollinated crops presentation
1. BREEDING TECHNIQUES IN SELF- POLLINATED CROPS
Dept of GPB &SST Allahabad school of agriculture
S.H.I.A.T.S. Allahabad (India )
,
Deva Ram
M.Sc Ag SST 12mssdci049
2.
3. Introduction
Plant breeding is an art or science as old as
agriculture, started since man learnt to cultivate
the plants. Plant breeding is considered as the
current phase of crop evolution. Selection of
desirable plant even today is an art which depends
on the skill of a person but skill alone is not
enough, modern plant breeding is based on
thorough understanding and use of genetics
principles.
4. Objectives of Plant Breeding
• The prime aim of plant breeding is
to improve the characteristics of
plants that they become more
useful automatically and
economically. Some of the
characteristics are as follows
• Higher yields
• Better Quality
• Disease and pest resistance
• Agronomic characters
• Moisture stress and salt tolerance
• Wider adaptability
5. Methodsof BreedingAutogamous species
The principle methods of breeding self pollinated crops are:
1. Plant Introduction
2. Pure line selection
3. Mass selection
4. Pedigree method
5. Bulk method
6. Backcross method
7. Mutation breeding
6. Brief account of breeding methods
Plant introduction
• According to Allard (1960) plant introduction is an oldest and rapid method of crop improvement.
Introduction may involve new varieties of a crop already grown in the area wild relatives of the crop
species or totally new crop species for that area. Plant introduction may within the country between the
countries or confirmed between the states or within the state. The plant may be introduced from the
country of another continent . It is the process of introducing crop plant into new areas.
• Ex. Introduction of Ridley wheat varieties from Australia.
a)Primary
When the introduced variety is well suited to the new environment and is directly released for commercial
cultivation without any change the original genotype, known as primary introduction. Ex. Introduction of
semi dwarf wheat varieties Sonora 64, Lerma Rojo and semi dwarf Rice Var. TN-1, IR-8, IR-28, and IR-36
Introduction may be classified in two categories:
b) Secondary
The introduced variety is subjected to selection, to isolate superior variety or may be hybridized with
local variety to transfer one or few desirable characters to the local variety, known as secondary
introduction. Ex. Kalyan sona and sonalika varieties selected from the material introduced from
CIMMYT. Mexico
7. Procedure of Plant Introduction:
i)Procurement of Germplasm:
While introducing germplasm
scientist has to allow two routes.
first route individual make a direct
request to individual or institution
abroad.
second route individual submit his
requirement to the NBPGR, by
giving much detail information
about the requirement.
The plant part to be introduced
depend upon the crop species,
The part of the plant used for the
propagation of a species is known
as propagule.
ii)Quarantine If necessary, the materials are grown in
isolation for observation of disease, insect, pest and
weeds, this entire process is known as quarantine and
the rules prescribed them are known as quarantine
rules. The quarantine controls is exercised by NBPGR at
prescribed part of entry. E.g. Mumbai, Calcutta and
Madras and this process is required at least three weeks.
iii) Cataloguing: The introduced material is entered in
accession register and is given on entry number. The
information regarding the name of the species, crop
variety, and place of origin, adoption and morphological
character are reduced. The plant materials are classified
into three groups viz.
a) Exotic Collection (EC)
b) Indigenous Collection (IC)
c) Indigenous Wild Collection (IW)
8. iv) Evaluation : To assess the potential of new introductions, their performance is evaluated at
different substations of the Bureau. In case of those crops for which Central Research
Institutes are functioning,
e.g., rice, sugarcane, potato, Tobacco etc., the introduced materials are evaluated and maintained
by these institutes. The resistance to diseases and pests is
evaluated under environments favouring heavy attacks by them.
v) Multiplication and Distribution: After evaluation promising material from production
may be increased by multiplication and released for general cultivation as varieties after
necessary trials. Most of there are identified for desirable character and maintain for future
use.
Acclimatization:
The process that leads to the adoption of a variety to a new environment is known as
acclimatization. Generally the introduced varieties perform poorly because they are often not
adapted to the new environment. The population having more variability is easily
acclimatized i.e. cross pollinated crops are easily acclimatized than self pollinated crop
9. Plant Introduction Agencies in India
• In India centralized plant introduction agency was initiated at IARI in 1946 at New Delhi. In 1956 it was
expanded as the “Plant Introduction and Exploration Organization” and in 1961, it was made an
independent division in IARI as the “Division of Plant Introduction”. In 1976 division was reorganized
as NBPGR This bureau is responsible for the introduction and maintenance of germplasm of Agricultural
and horticultural crops.
In addition to bureau there are some other agencies
1.FRI (Forest Research Institute):
2.Botanical Survey of India:
3.The Central Research Institute:
4. NBPGR:
10. Achievement of Plant Introduction
I) New Crop Species:
The crop introduced in India includes Potato, Maize, Chilly, coffee. Hevea rubber, guava,
grape, papaya, soybean, Jojoba.
II) Directly Released as Varieties:
Semi dwarf wheat varieties, sonara-64 and lerma Rajo introduced from Mexico. TN-1 rice
variety introduced from Taiwan and other varieties IR-8, IR-28 and IR-36 introduced from
IRRI Philippines, pea, Rice, Wheat from Australia.
11. Merits of Plant Introduction
1. It provides entirely new crop plants.
2. It provides superior varieties either directly or after selection & hybridization.
3. Introduction and exploration are the only feasible means of collecting germplasm and
to protect variability from genetic erosion.
4. It is very quick & economical method of crop improvement, particularly when the
introductions are released as varieties either directly or after a simple selection.
5. Plants may be introduced in new disease free areas to protect them from damage, e.g.,
coffee and rubber.
Demerits of Plant Introduction
The disadvantages of plant introduction are associated with the introduction of weeds, diseases
and pests.
12. Method of Plant Breeding in Self Pollinated Plants
Selection
One of the oldest method of breeding and is the basis for all crop improvement, practiced by farmer in
ancient times. Selection is essentially based on the phenotype of plants. Consequently the effectiveness
of selection primarily depends upon the degree to which the phenotypes of plants reflect their genotype.
Two methods of selection are practiced in breeding self pollinated crops
i)Pure Line Selection
ii) Mass Selection.
13. Pure line selection
Pure line selection has been the most commonly used method of improvement of self
pollinated crops. Almost all the present day varieties of self pollinated crops are pure lines.
Pure line selection has several applications in improvement of self pollinated crops. It is used
to improve.
1. Local varieties
2. Old pure line varieties and
3. Introduced varieties
General procedure for evolving a variety by pure line selection
The pure line selection has three steps.
1. Selection of individual plants from a local variety or some other mixed population.
2. Visual evaluation of individual plant progenies and
3. Yield trials
14.
15. Advantage of pure line selection
1. The pure lines are extremely uniform since all the plants in the variety will
have the same genotype.
2. Attractive and liked by the farmers and consumers.
3. Pure lines are stable and long test for many years.
4. Due to its extreme uniformity the variety can be easily identified in seed
certification programmes.
disadvantages of pure line selection
1. New genotypes are not created by pure line selection
2. This method is applicable to sell pollinated crop only.
3. Improvement is limited to the isolation of the best genotype present in population.
16. Achievements :
Several varieties developed by pure line selection were released in many crops.
Some examples are given below
Rice : Mtu-1, Mtu-3, Mtu-7, Bcp-1, Adt-1, 3, 5, and 10
Sorghum : G 1 & 2, M 1 & 2, OO 1, 4 & 5,
Groundnut : TMV 3, 4, 7, 8 and Kediri 71-1
Red gram : TM-1, ST-1
Chillies : G1 & G2
Ragi : AKP 1 to 7
17. MASS SELECTION
It is the earliest method of selection. Man has always practiced mass selection
consciously or unconsciously from the time of domestication. In its most basic form mass
selection consists of selecting individuals on the basis of phenotypic superiority and mixing
the seeds for using as planting material for next season.
18. Procedure for evolving variety by mass selection
First year : Large number of phenotypically similar plants having desirable characters are
selected.
Second year : composited seed planted in a preliminary field trial along with standard
checks.
Third to fifth year : The variety is evaluated in coordinated yield trials at several locations.
Six year : if the variety is proved superior in main yield trials it is multiplied and
released after giving a suitable name.
19.
20. Merits of Mass selection :
1. Can be practiced both in self and cross pollinated crops
2. The varieties developed through mass selection are more widely adopted than pure
lines.
3. It retains considerable variability and hence further improvement is possible in future
by selection
4. Helps in preservation of land races
5. Useful for purification of pure line varieties
6. Improvement of characters governed by few genes with high heritability is possible.
7. Less time consuming and less expensive.
Demerits of mass selection
1. Varieties are not uniform
2. Since no progeny test is done, the genotype of the selected plant is not known
3. Since selection is based on phenotype and no control over pollination the
improvement brought about is not permanent. Hence, the process of mass selection
has to be repeated not and then.
4. Characters which are governed by large number of genes with low heritability can not
be improved.
5. It can not create any new genotype but utilizes existing genetic variability
21. Achievements
Mass selection must have been used by pre historic man to develop present day
cultivated cross from their wild parents. It was also used extensively before pure line
selection came into existence.
Cotton : Dharwad American Cotton
Groundnut : TMV-1 & TMV-2
Bajra : pusa moti, Baja puri, Jamnagar gaint, AF3
Sorghum : R.S. 1
Rice : SLO 13, MTU-15
Potato : K122
22. HYBRIDIZATION
A crossing or mating of two plants of dissimilar genotype is known as HYBRIDIZATION.
A X B F1
The seeds as well as progeny resulting from the hybridization are known as HYBRID or F1.
The progeny of F1 obtained by selfing or intermating of F1 plants and subsequent generation
are termed as SEGREGATING generation.
Types Of Hybridization
Based on the taxonomic relationship of the two parents, hybridization may be classified into
two broad groups:-
1) Intervarietal Hybridization
2) Distant Hybridization
23. Intervarietal Hybridization: The parents involved in hybridization belong to the same
species.
The Intervarietal crosses may be simple or complex depending upon the number of
parents involved.
a) Simple Cross:
In simple cross, two parents are crossed to produce the F1. The F1 is self to produce
F2 or is used in a back cross programme.
E .g A X BF1
b) Complex Cross:
More than two parents are crossed to produce the F1 hybrid, which is then used to
produce F2 or used in back cross. The cross is also known as convergent cross,
because it brings genes from several parents into a single hybrid.
E.g. A, B, C (Three Parents)
A X B F1 X C = Complex hybrid (AX B) X C
24. 2) Distant Hybridization
Distant hybridization includes crosses between different
species of the same genus or of different genera.
When two species of same genus is crossed ,it is known
as INTERSPECIFIC HYBRIDIZATION.
e.g. Oryza sativa var.indica X O. perennis CO 31 rice
variety
When two species of different genera are crossed, it is
known as INTERGENERIC HYBRIDIZATION.
e.g. Triticum sp. X Secale cereale triticale
25. Objective and aim of hybridization
• The chief objective of hybridization is to create genetic variation.
• The aim of hybridization may be transfer of one or few qualitative characters, the
improvement in one or more quantitative character or the use of F1 as a hybrid variety.
These objectives are grouped into two classes
1) Combination breeding
2) Transgressive breeding
1) Combination breeding
The main aim of combination breeding is the transfer of one or more characters into a single
variety, from other varieties. These characteristics may be governed by oligogenes or
Polygene
2) Transgressive breeding
Transgressive breeding aims at improving yield or its contributing character through
Transgressive segregation. Transgressive segregation is the production of plants in F2
generation that are superior to both the parents for one or more characters.
26. Procedure of hybridization
There are seven steps are involved in
hybridization
1. choice of parents
2. evaluation of parents
3. emasculation
4. bagging
5. tagging
6. pollination
7. harvesting
8. threshing, drying and storage of
F1 seeds.
28. The pedigree may be define as a description of the ancestors of an individual
and it generally goes back to some distant ancestor or ancestors in past .
In pedigree method, individual plants are selected from F2 and the
subsequent generations, and their progenies are tested.
Pedigree Record:
During the entire operation, a record of all the parent offspring relationship is
kept; this is known as pedigree record.
It should be simple and accurate.
PEDIGREE METHOD
Generation Number Description
F3 7911-7 Progeny in 7th row in the F3 plot
F4 7911-7-4 Progeny in the 4th row of F4 Plot
selected from 7th row of F3
F5 7911-4-14 Progeny in the 14th row selected from
4th row of F4. in the F5 Plot
30. Application of Pedigree Method:
The pedigree method is the most commonly used method for selection from
segregating generations of crosses in self pollinated crops.
It is also very useful in the selection of new superior progeny.
This method is also suitable for improving specific characteristics such as disease
resistance , plant height, maturity time etc.
Pedigree method depends on
1)Basis of selection:
2)Early generation tests
objective of early tests is to select superior crosses and plants from within superior
crosses.
31. Merits and Demerits of Pedigree Method
MERITS:
• Provide maximum opportunity
for the breeder to use his skill
and judgments for the selection
of plants, particularly in the
early segregating generations
• Improvement of characters
which can be easily identified
and are simply inherited.
• Take less time than the bulk
method.
• Plants and progenies with
visible defects and weaknesses
are eliminated at an early
stage.
• Pedigree record helps breeder
to obtain information of
inheritance of qualitative
characters.
32. DEMERITS:
• maintenance of accurate pedigree records take time.
• Selection among and within a large number of progenies in every generation is
laborious and time consuming.
• Success of this method largely depends upon the skill of breeder.
• Selection for yield in F2 and F3 is ineffective. If care is not taken to retain a
sufficient number of progenies, valuable genotypes may be lost in the early
segregating generations.
33. Bulk Breeding
It is also known
as mass method
or population
method of
breeding
It was first
used by
Nilson Ehle in
1908
A species is grown in
bulk plot ( from F1 to F5 )
with or without
selection, a part of the
bulk seed is used to grow
the next generation and
individual plant selection
is practised in later
generation.
34. Procedure for Bulk Method of Breeding
Hybridization Crossing among selected parents
F1generation
F1 seeds (minimum 20) planted.
Bulk harvesting is carried out.
F2 to F6generation
F2 to F6 are planted, harvested
in bulk. Number of plants
should be as large as possible.
Generally artificial selection is
not carried out.
F7generation
Generally 30 to 50 thousand
F6 seeds are space planted,
selection is carried out based
on phenotype and 1000 to
5000 selected ones are
harvested separately.
35. F8generation
Individual plant progenies
are grown, inferior
progenies eliminated.
Harvested in bulk.
F9generation
Preliminary yield trials with
standard varieties as check.
Selection is based on yield.
F10 to F13generation
Multi location yield trials are
conducted using standard
varieties as check.
Evaluation of performance of
lines is done.
F14generation
Seed multiplication for
distribution.
36. Merits
This method is simple, convenient and
inexpensive. It eliminates undesirable types
and increases the frequency of desirable
types by artificial selection.
Demerits
It takes much longer to develop a new
variety. It is suitable for self pollinated crops
only. Natural selection may also work
against desirable traits.
37. Application of Bulk Breeding Methods
This method is suitable for handling the
segregating generation of cereals, smaller
millet, grain legume and oilseeds.
This may be used for three different
purposes.
i.)Isolation of homozygous lines.
ii.)Waiting for the opportunity of
selection.
iii.)Opportunity for natural selection to
change the composition of the
population.
38. Achievements
This method has between used in Barley crop for
developing some varieties from the crosses (
Allas X Vaughn), like Arival, Beecher, Glacier, etc
In India only one variety “Narendra Rai” has
been developed in Brown Mustard.
39. Backcross Method
A cross between F1 hybrid and one of its
parents is known as a backcross. It is
proposed by Harian and Pope in 1922, as a
method of breeding for small grains
Backcrossing has been used for decades to
transfer specific character into elite lines.
The variety which receives gene is
‘recipient parent’ and variety which is the
source of gene is called as ‘donor parent’
Recipient parent is used repeatedly hence
also named as ‘recurrent parent’. Donor
parent is ‘non-recurrent parent’. Repeated
backcrossing leads to homozygosity.
40. Procedure of Backcross Breeding in Self Pollinated
crops
Objective: to improve one or more defects
of a high yielding variety
Let, P1 be a well adapted and high yielding
variety.
P2 be another variety resistant to a specific
disease; which is governed by a dominant
gene. We wish to transfer this dominant
gene P2 to P1
So P1 – recurrent parent (♀)
P2 – donor parent (♂)
Hybridization – The two varieties P1 and P2
are crossed
F1 generation – Plants from F1 seed are back
crossed with recipient variety P1
First backcross generation (BC1) – Selection
is done for disease resistance and selected
ones are back crossed with recurrent parent
P1
41. Second to fifth backcross generation
(BC2 to BC5) – Segregation for disease
resistance occurs in every back cross generation.
Plants are selected on the basis of similarity with
recurrent parent and resistance to disease.
Selected ones are back crossed with recurrent
parent P1.
Sixth backcross generation (BC6) – Disease
resistance plants are selected. They are self
pollinated and harvested separately.
BC6 F2 generation – Individual plant progenies
are grown from seeds of BC6 generation. Plants
are selected on the basis of similarity with
recurrent parent and resistance to disease. They
are harvested separately.
BC6 F3 generation – Individual plant progenies
are grown from seeds of above cross. As done in
above step plants are selected on the basis of
similarity with recurrent parent and resistance to
disease but harvested in bulk.
Yield trials – Replicated yield trials are
conducted with recurrent parent as a check. The
newly constituted variety should be similar to
variety P1 for most of the important
characteristics. Seeds are multiplied for
distribution.
42. • Merits:
• It is not necessary to test
the variety developed by
this method because the
performance of recurrent
parent is already known
• It does not require record
keeping
• It is not affected by
environmental conditions
43. Demerits
• Undesirable genes may
also be transferred to the
new variety.
• Hybridization has to be
done for each backcross
so time required is more.
• New variety cannot be
superior to the recurrent
parent except for the
character transfer from
donor parents
44. Application of Backcross Breeding
This method is commonly used for the transfer of
disease resistant from one variety to another. But is
also suitable for the transfer of quantitative characters
and is applied is both self and cross pollinated crops.
Intervarietal transfer of simply inherited characters
such as disease resistance , seed colour , plant
height etc.
Intervarietal transfer or quantitative characters. Such
as earliness, seed size, seed shape may be transferred
from one variety to another belongings to same
species.
45. Achievements
Backcross method has been
widely used for the development
of disease resistant varieties in
both self and cross pollinated
crops
Wheat- Kharchia 65, NP-853, NI-
5439 etc.
47. INTRODUCTION
Mutation refers to sudden heritable change in the phenotype of an
individual. In the molecular term, mutation is defined as the permanent
and relatively rare change in the number or sequence of nucleotide.In other
words, mutations arise due to change in DNA bases.
Mutation occurs in two ways :
(1) By alteration in nuclear DNA ( point mutations))
(2) By change in cytoplasmic DNA(cytoplasmic mutation))
The best example of useful cytoplasmic mutation is cytoplasm male sterility.
48. TYPES OF MUTATION
A. Spontaneous mutations : Mutation occur in natural
populations .
B. Induced mutations: Mutation may be artificially induced by
various mutagenic agents. Induced mutations are of two types:
1.Macro-mutations: Mutation with distinct morphological
changes in the phenotype.
2.Micro-mutations: Mutations with invisible phenotypic
changes.
49. MUTATION BREEDING
Inducing desirable mutations and exploiting them for crop
improvement. It is commonly used in self pollinated crops and
used to produce traits in crops such as larger seeds ,new
colour.
Mutagen : Physical or chemical agent which greatly
enhance the frequency of mutation
Types of mutagens:
A.Physical mutagens:
1.Ionising radiation:
(a)Particulate radiations: alpha-rays , beta-rays, fast neurons
and thermal neurons.
(b) Non-particulate radiations:x-rays,and gamma rays.
2.Non-ionising radiation: ultraviolet radiation.
50. Type of radiation properties Mode of action/changes caused
1.x-ray S.I , penetrating and non-
particulate
Induce mutations by forming free
radicals and ions.
2.Gamma-ray S.I,very penetrating and non-
particulate
Induced mutations by ejecting
atoms from the tissues.
3.Alpha-particles D.I,particulate ,less
penetrating and positively
charged.
Act by ionization and
excitation.Cause chromosomal
and gene mutations.
4.Beta rays particulars S.I,particulate, more
penetrating than alpha
particles and negatively
charged.
Act by ionization and
excitation.Cause chromosomal
and gene mutations.
5.Fast and thermal
neutrons
D.I, particulate,neutral Cause chromosomal breakage and
gene mutations.
6.Ultra violet Rays Non-ionising ,low penetrating Cause chromosomal breakage and
gene mutations.
Physical mutagens(radiations), their properties and mode of action
52. l
M1FIRST YEAR
SECOND YEAR
THIRD YEAR
i) Treated seeds are space-planted
ii) Seeds from individual plants are
harvested separately
i) Individual plant progenies grown
ii) Seeds from all the plants of each
row containing or suspected to
contain the mutant allele harvested
separately.
llllllllllllll
llllllllllllll i)Individual plant progenies are
grown.
ii)Superior mutant lines harvested in
bulk if they are homogeneous.
ii)In heterogeneous progenies,
individual plants may be selected.
M2
M3
MUTATION BREEDING FOR OLIGOGENIC TRAITS
53. FOURTH YEAR M4 i)Preliminary yield trial with a
suitable check.
ii) Superior lines selected.
FIFTH –
SEVENTH
YEARS
M5-7
i)Replicated yield trial at several
locations.
ii) Outstanding line released as a
new variety.
EIGHT
YEAR M8
Seed multiplication for
distribution among farmers.
Fig: A generalised scheme for mutation breeding for oligogenic trait.
54. Use of viable and fertile mutant in rice
Rice is basically a self pollinating plant, however, the mutational
event may be much lower than the assured self pollinating rate.
Therefore in the M1 planting field (upper left light green
(variety ‘Reimei’) and lower right light green (variety
‘Norin-8’)) previously induced and increased light green and
fertile“chlorina” mutants were used to assure the line purity.
An example of M2 field planted with panicle to
row system. Indicator poles show some kind of
mutants were segregated in the family line.
Two early flowering mutants are shown here as
they segregated in panicle to row planting in a
M2 field.
55. Fertile twin grain mutant has two sets of pistils,
suggesting better external pollen reception. This
recessive mutation will not be expressed in the F1.
Flower of the twin grain mutant has two pistils, both are fertile, if condition allows.
These characters expressed in the maternal tissues may be screened in the M2 generation
field (in case of the “twin grains” flowers in M2 plants, and
seeds shown above are in M3 generatiòn).
In rice the flowering time of the day is not long, a few
hours in the morning. This open hull mutant keeps
open its flowers, or can not close. However, this
mutant has good seed fertility as shown in this picture.
56. APPLICATIONS IN CROP IMPROVEMENT
1.Development of improved varieties : In india ,improved
varieties have been developed through mutation breeding in
wheat ,rice,barley etc.Besides high yield , varieties with
better quality,earliness,dwarfness,disease resistance and low
toxin contents have been developed in various crop.
2.Induction of male sterility: GMS has been induced in durum
wheat and CMS induced in barley. Its reduces the cost of
hybrid seed production.
3.Creation of variability :Induced mutations have been used for
increasing the range of genetic variability in barley, wheat.
4.Improvement in Adaptation: Induced mutations play an
important role in improving adaptation of some crops.
57. ACHIEVEMENTS OF MUTATION BREEDING
1.In plant species, 2252 mutant varieted have been developed in
over the world.Of these 1585 have been released directly and
667 through the use of mutants in hybridization.
2.Out of 2252 mutant varieties ,1700 have been released in seed
propagated crops and 552 in vegetatively propagated species.
3.Among seed propagated species, the maximum mutant
varieties have been developed in rice (434),followed by barley
(269), and wheat (222).
4.Maximum varieties have been developed through radiations.
5.Among the chemical mutagenes,EMS resulted in the
development of maximum mutant varieties.
6.In india, 259 mutant varieties have been developed.
7.Maximum mutant varieties have been released in cereals
(1072).
58. Improved character Crops and mutant varieties
Higher yield Barley (DL 253), Pea (Hans), Groundnut
(Co 2, TG 17).
Short stature Barley (RDB 1),Rice (Prabhavati).
Earliness Rice (IIT 48,IIT 60,Indira,Padmini)
Stress resistance Salt tolerance in Rice (Mohan) and
water logging tolerance in jute (
Padma)
Bold seed size Groundnut (PB 1,PB 2,Vikram) and Rice
( Jagannath)
Improvement achieved in different characters through
mutation breeding in some crops in India :
59. 1. Induced mutagenes is used for the induction of CMS.
Ethidium bromide (EB) has been used for induction of CMS
in barley.
2. Mutation breeding is a cheap and rapid method of
developing new varieties.
3. Mutation breeding is more effective for the improvement of
oligogenic characters.
4. Mutation breeding is the simple, quick and the best way
when a new character is to be induced.
DEMERITS OF MUTATION BREEDING
1.Most of the mutations are deleterious and undesirable.
2.Identification of micro-mutations, which are more useful to a
plant breeder is usually very difficult.
3.Mutation breeding has limited scope for the genetic
improvement of quantitative or polygenic characters.
MERITS OF MUTATION BREEDING
60. Conclusion
Today crop plants are different from the crop from which
they are originated i.e. it’s wild species. This change has
been brought by man through plant breeding. The
important achievement of plant breeding are :
Production of dwarf and semi dwarf cereal varieties in
wheat and rice
Development of hybrid and synthetic varieties in crops.
61. Plant Breeding has a very important role
to play in the future. It can be used as a
tool for intensive breeding of pulses and
oilseed crops, developing high yielding
varieties in vegetables and oilseed crops
and for the development of varieties
desirable for mechanical threshing and
cultivation
