Mutation breeding is a tool for crop improvement that induces mutations using physical or chemical mutagens. Over 3,200 mutant varieties have been released globally in over 70 plant species. Key milestones included the first induced mutations in plants in 1927 and development of the first induced mutant variety in 1936. Procedures involve choosing plant material, applying mutagens like radiation or chemicals, handling mutated plants, and screening generations to select desirable traits. Successful examples include developing semi-dwarf, disease resistant, early maturing, and stress tolerant rice, wheat, barley, peanut, and chickpea varieties. Mutation breeding has made major contributions to global food production.

1. Presented By:
Yogendra Katuwal
AGR-O3 M, 2016
Department of Agronomy
AFU, Rampur, Chitwan
A faster tool, yet,
Environmentally friendly

2. INTRODUCTION
 Mutation refers to sudden heritable change in the phenotype of an individual.
Mutation may be the change in gene, chromosome or plasmagene (genetic
material inside mitochondria and chloroplasts.
 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.
 The term mutation breeding (‘Mutationszüchtung’) was first coined by Freisleben
and Lein (1944). He referred mutation breeding as the deliberate induction and
development of mutant lines for crop improvement.
Mutation breeding is a fundamental and highly successful tool in the global
efforts of agriculture to feed an ever increasing and nutritionally demanding
human population.

3. MILESTONES
 1927 - First proof of induced mutations in plants; radium ray treatment of
Datura stramonium (Gager and Blakeslee).
 1927 - Muller working with Drosphila provides proof of mutation
induction by X-rays that induced mutation for animal and plant breeding
and opens a new era in genetics and breeding.
 1928 - Stadler in 1928 first used X-rays for induction of mutation in barley.
 1936 - The first induced mutant variety was released, tobacco var.
‘Chlorina’ using X-rays in Indonesia.
 1942 - First report of induced disease resistance in a crop plant; X-ray
induced mildew resistance in barley (Freisleben and Lein, 1942).
 1944/46 First reports of chemical induced mutation (Auerbach and
Robson, 1944).
 Father of mutation breeding - Ake Gustafsson.

4. 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.

5. MUTATION BREEDING
 Inducing desirable mutations and exploiting them for crop improvement.
 Mutation breeding is commonly used to produce traits in crops such as
larger seeds, new colors, or sweeter fruits, that either cannot be found in
nature or have been lost during evolution.

6. PROCEDURES OF MUTATION BREEDING
Choice of material : It should be the best variety available in crop and seed
should be pure.
Choice of mutagen : Depends upon the plant parts to be treated. Generally,
chemical mutagens are more preferred for seed treatment and radiation for
treatment of vegetative parts.
Mutagenic treatment : In seed propagated species, generally, seed are
treated. In vegetatively propagated species, buds, suckers or cuttings are
LD50 is the dose of mutagen that kills 50% of the treated individuals.
of treatment depends on intensity of radiations or concentration of chemical
mutagens.
Optimum mutagen dose is one, which produces maximum frequency of
mutations and causes the minimum killing.
Handling of treated material : The handling of mutagen treated material

7. MUTAGENS
 Mutagen : Physical or chemical agent which greatly enhance the frequency
mutation.
 Mutant: Is an individual, organism, or new genetic character, arising or resulti
from an instance of mutation.
Types of mutagens:
A. Physical mutagens:
1. Ionising radiation:
• Particulate radiations: alpha-rays , beta-rays, fast neurons and thermal neurons.
• Non-particulate radiations: x-rays and gamma rays.
2. Non-ionising radiation: ultraviolet radiation.

8. MUTAGENSB. Chemical mutagens:
1. Alkylating agents: Cause mutation by
adding alkyl group at various positions
in DNA. Eg: EMS (ethyl methane
sulphonate), methyl methane
sulphonate (MMS), sulphur mustard,
nitrogen mustard
2. Acridine dyes: They are very effective
mutagens. Leads to addition or
and cause frame-shift mutations. Eg:
Proflavin, acridine orange, acridine
yellow
3. Base Analogues: Chemical compounds
similar to DNA bases. Eg: 5 Bromo
Uracil, 5-chlorouracil.
4. Other mutagens: Nitrous Acid, Sodium
Azide.

9. GENETIC STRUCTURE CHANGES:
Gene (point mutation)
Change in specific sequence of nucleotides in DNA molecules leading to
formation of a new type of protein or preventing that of the normally
protein
Chromosomal mutation:
Deletion or deficiency (loss of a chromosomal segment),
Duplication (doubling of a chromosomal segment),
Inversion (rearrangement of a group of genes in a chromosomal
in a such a way that their order is reversed) and
Translocation (change in position of a chromosome or exchange of
chromosome segments)
Genome mutation: Changes in sets of chromosomes.

10. PROCESS

12. HANDLING OF SEGGREGATING POPULATION
M1 GENERATION
 Seeds treated with chemical mutagens should be washed thoroughly and be
be planted as soon as possible.
 Large M1 generation is raised from treated seeds (Wider spacing). E.g:
25,000 plants are to be grown to obtain a useful mutation in M1 generation.
 Mutagens if has high mutation frequency, then M1 generation size can be
reduced.
 The M1 plants should not be allowed to cross pollinate.
Dominant mutations are selected and each plants are selfed and harvested
separately for M2
M2 GENERATION
Two methods of sowing M2 generation can be followed
 M1 plant to row where all seeds produced from a single plant are grown in
row
 M1 spike or branch to row

13. SCREENING/SELECTION
 Mainly three types screening/selection
techniques are used in M2 and
subsequent generation.
1. Visual: Most effective and efficient
method for identifying mutant
phenotypes.
2. Mechanical/Physical: Very efficient for
seed size, shape, weight, density, etc.
using appropriate sieving machinery.
3. Other methods: Low alkaloid content
mutants can be selected using
colorimetric tests. Chromatographic or
electrophoresis techniques may be used
to select isolate protein variants

14. ADVANTAGES OF MUTATION BREEDING
Mutation breeding is a cheap and rapid method of developing new
varieties.
Induction of desirable mutant allele, which is not present in germplasm .
Induced mutagens is used for the induction of CMS. Ethidium bromide (EB)
has been used for induction of CMS in barley.
Mutation breeding is more effective for the improvement of oligogenic
characters.
Production of haploids by irradiating pollens.
Mutation breeding is the simple, quick and the best way when a new
character is to be induced.

15. MORE THAN 3,200 MUTANT VARIETIES INCLUDING NUMEROUS
CROPS (75 %), ORNAMENTALS AND TREES (25 %) HAVE OFFICIALLY
BEEN RELEASED FOR COMMERCIAL USE IN MORE THAN 210 PLANT
SPECIES FROM OVER 70 COUNTRIES
(SOURCE: FAO/IAEA MUTANT VARIETIES DATABASE).
PERCENTAGE OF MUTANT VARIETIES BY CROP TYPE

16. GLOBAL DISTRIBUTION OF MUTANT VARIETIES

17. HIGHLIGHTS OF SOME GLOBAL MUTANT VARIETIES
1 GENETIC ENHANCEMENT OF RICE
The impact of induced rice mutants in applied research is best
by the development of improved rice varieties through mutation
During the past five decades, more than 800 varieties of rice have been
developed across the globe, either directly from induced mutations or as
result of crossing such mutants with other breeding lines.
The first rice varieties KT 20-74 and SH 30-21, developed through
mutation, were released in China in 1957
Afterwards, the semi dwarf mutant Reimei was released in Japan which
have significantly increased yield because of their lodging resistance.
Calrose 76 and Basmati 370, semi dwarf varieties of rice with short and
straw has revolutionized the rice production in USA and Pakistan

18. contd
2 DEVELOPING DROUGHT AND SALINITY TOLERANCE IN WHEAT CROP
‘Sharbati Sonora’, a semi dwarf and non-lodging mutant variety has
a significant contribution to wheat production in India.
‘Sharbati Sonora’ was produced from red grained Mexican variety
60’ by gamma irradiation at the IARI, New Delhi, India.
A high yielding mutant Stadler, developed in Missouri, USA had
to leaf rust and loose smut, better lodging resistance and early maturity.
In Italy Durum wheat cultivation area was significantly expanded due to
the cold tolerant mutant varieties.

19. contd
3 Enhancing lodging resistance in Barley crop
Mutation breeding has been very successfully used in breeding barley, the
introduction of ‘Diamant’ and ‘Golden Promise’ a gamma-ray induced semi-
dwarf mutant revolutionized brewing industry in Europe.
‘Luther’, gamma ray induced mutant had 20% increased yield, higher
and lodging resistance and ‘Pennrad’, had winter hardiness, better lodging
resistance and early ripening [46].
4 Developing early maturing varieties of Peanut
5 High yielding and wilt disease resistant chickpea mutants
6 Improvement in Ornamental plants
7 Major economic successes in USA (rice, barley, sunflower, grape fruit),
Pakistan (cotton), India (blackgram), Australia & Canada (linseed), Japan

20. LIMITATIONS
The process is generally random and unpredictable.
Useful mutants are rare and predominantly recessive.
Mutants can have strong negative pleiotropic effects on other traits.
Health risks: handling, chemical mutagens; radiations, fast neutrons
treatments.
Most mutants are of no use to breeding even if a large number of mutants
can be produced.
Field trialing and germplasm storage can be expensive and require a lot of
space and careful management if large mutant populations are handled.

21. CONCLUSION
Applied since the 1930s to accelerate the process of developing and
selecting new valuable agronomic traits, mutation breeding uses a plant’s
own genetic make-up, mimicking the natural process of spontaneous
mutation.
The mutation process generates random genetic variations, resulting in
mutant plants with new and useful traits.
Mutation breeding is built on mutation induction and mutation detection.
It has many comparative advantages: it is cost effective, quick, proven and
robust. It is also transferrable, ubiquitously applicable, non-hazardous and
environmentally friendly.
Crop varieties generated through the exploitations of mutation breeding
are significantly contributing to global food and nutritional security and
improved livelihoods.