This document discusses mutation breeding in plants. It begins by defining key terms like mutation, mutagen, and mutant. It then describes the history of mutation breeding, which began in the 1920s with experiments exposing plants to radiation. The document outlines different types of mutations and mutagens used, including physical mutagens like radiation and chemical mutagens. The breeding process is explained as inducing mutations, screening mutants for desirable traits, and releasing improved varieties. Advantages include developing new varieties quickly, while disadvantages include the unpredictability of mutations. The document concludes by listing achievements of mutation breeding programs in India.

1. Mutation Breeding in
Plants

2. Introduction
• The word mutation is derived from Latin word
“mutatus” meaning “changed”
• In biology, a mutation is the permanent alteration of
the nucleotide sequence of the genome of an
organism, virus or extra-chromosomal DNA or other
genetic element.
• Refers to sudden heritable change in the phenotype
of an individual.
• Mutation breeding: referred to as variation breeding
is the process of exposing plants or seeds to chemical
or radiation in order to generate mutants with
desirable traits to be bred with other cultivars (plant
varieties)
• Plants/seeds created using mutagenesis are called
mutagenic plants or mutagenic seeds.

5. • Mutant: A mutant is an organism or a new genetic
characters arising or resulting from mutation which
is an alteration of the DNA sequence of a gene or
chromosome of an organism.
• From 1930 to 2014 more than 3200 mutagenic
plant varieties were released & still counting.
• From direct mutation 70% and from their progeny
30%
• Natural occurrence of genetic mutation is integral
to the process of evolution
• Mutation occurs in two ways :
(1) By alteration in nuclear DNA (point mutations)
(2) By change in cytoplasmic DNA (cytoplasmic
mutation)

7. History
• 1927 – First proof of induced mutations in
plants; radium ray treatment of Datura
stramonium (Gager and Blakeslee).
• 1927 – H. J. Muller working with Drosphila
provides proof of mutation induction by X-rays,
Muller champions induced mutation for animal
and plant breeding and opens a new era in
genetics and breeding.
• 1928, Stadler publishes the first results of
mutation induction in crop plants, barley,
maize, wheat and oat, etc.

8. • 1936, The first induced mutant variety is
released, tobacco variety-‘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).
• 1944/46 First reports of chemical induced
mutation (Auerbach and Robson).

9. TYPES OF MUTATION

10. TYPES OF MUTATION
1. Spontaneous mutations: Mutation occur in natural
populations. Natural exposure of a plant to certain
environmental factors, such as ultraviolet light and
chemical carcinogens (e.g., Aflatoxin B1). A
common cause of spontaneous point mutations is
the de-amination of cytosine to uracil in the DNA
double helix.
2. Induced mutations: Mutation may be artificially
induced by various mutagenic agents.
Induced mutations are of two types:
i) Macro-mutations: Mutation with distinct
morphological changes in the phenotype.
ii) Micro-mutations: Mutations with invisible
phenotypic changes.

12. De-amination of cytosine to uracil

14. 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,
greater yields, etc.
Important steps to know before mutation breeding are:
1.Selection of variety for mutation breeding, It should be
the best variety available in crop and Seed should be pure
2.Part of the plant to be treated
3.Dose of the mutagen (LD50): Mutagens generally induce a
high
frequency of chromosomal changes and meiotic and mitotic
irregularities, Optimum mutagen dose is one, which
produces maximum frequency of mutations and causes the
minimum killing.

15. MUTAGENS
• 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 neutrons and thermal neutrons.
(b) Non-particulate radiations: x-rays and
Gamma rays.
2.Non-ionising radiation: ultraviolet radiation.

16. B. Chemical mutagens:
1.Alkylating agents: EMS `(ethyl methane
sulphonate), methyl methane sulphonate
(MMS),sulphur mustard, nitrogen mustard
2.Acridine dyes: Proflavin, acridine orange,
acridine yellow and ethidium bromide.
3.Base Analogues: 5 Bromo uracil, 5 chloro-uracil.
4.Other mutagens: Nitrous Acid, Sodium Azide.

17. BREEDING PROCEDURE

19. 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 (method of
determining the concentration of a chemical
element or chemical compound in a solution with
the aid of a colour reagent), chromatographic or
electrophoresis techniques may be used to select
isolate protein variants

20. Advantages of mutation breeding
• Mutation breeding is a cheap and rapid method
of developing new varieties.
• Induced mutagens are used for the induction of
CMS (Cytoplasmic male sterility). Ethidium
bromide (EB) has been used for induction of CMS
in barley.
• Mutation breeding is more effective for the
improvement of oligogenic characters (a trait
that is influenced by more than one gene).
• Mutation breeding is the simple, quick and the
best way when a new character is to be induced.

21. Disadvantages
• 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 trialling and germplasm storage can be
expensive and require a lot of space and careful
management if large mutant populations are
handled.

22. The primary research centres and institutes in
India that participated in the development and
release of various mutants
Indian Agricultural Research Institute (IARI)--
New Delhi
Bhabha Atomic Research Centre--Mumbai
Tamil Nadu Agricultural University--TN and
National Botanical Research Institute--Lucknow,
UP

23. Achievements of mutation breeding
• 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)
• water logging tolerance in jute (Padma)
• Bold seed size Groundnut (PB 1,PB 2,Vikram)
and Rice (Jagannath).