CBO’s Recent Appeals for New Research on Health-Related Topics
Application of Mutation Breeding Techniques for Crop Variety Development
1. 1
WELCOME TO THE PRESENTATION
ON
Application of Mutation Breeding
Techniques for Crop Variety
Development
Dr. M. A. Malek, CSO & Head
Plant Breeding Division
3. 3
Importance of developing new crop
varieties
To feed the increasing population from the
decreasing cultivable land facing unfavorable
climatic conditions ;
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Growing Population
By 2041, the population of
Bangladesh will reach 220 million,
33% higher than today.
In order to feed this increasing
population, food production must
increase proportionately.
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Develop more tolerant varieties
to face drought, salinity, flood,
temperature (high or low) etc.;
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i. Genetic impurity due to poor maintenance of
the varieties,
ii. Becoming susceptible to diseases and insect-
pests due to the development of virulent
races/biotypes of pathogens/insect-pests,
iii. Natural mutations
Varietal deterioration:
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Plant Breeding deals with changing the genotype
of plants to be more useful to humans.
In true sense, plant breeding has
been practiced since near the
beginning of human civilization.
So, any plant breeding program aims to
develop plant varieties superior to
existing ones in yielding ability or any
other desirable traits.
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Higher yield;
Early maturity;
Improved quality for consumers preference;
Tolerance/resistance to biotic factors to
ensure yield loss;
Tolerance to abiotic factors to bring non-
cultivable land under cultivation;
Shattering resistance to reduce yield loss;
Some major objectives of plant variety
development:
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Synchronous maturity for easier harvest and
lowering the production cost;
Improving agronomic characteristics like plant
height, branching, erect or trailing habit;
Lodging resistance to avoid risk of yield loss;
Photo-insensitivity for growing round the
year;
Thermo-insensitivity for growing under high
temperature;
Contd.
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i. Presence of genetic variation and
ii. Selection
Two basic requirements of Plant Breeding:
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Plant breeding requires genetic variation
of useful traits for crop improvement.
If all the plants in a population are
similar for any character, improvement
in that character is not possible.
Therefore, in any breeding program,
creation of genetic variation is always
the first step.
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Selection is the next/second step
in crop improvement.
It involves the identification and
isolation of desirable plants having
desirable combinations of characters
depending on breeding objectives.
Selection is mainly based on phenotype
and finally results in an improved line
or variety.
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There are different plant
breeding methods for
developing crop varieties
and mutation breeding is
one of them.
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Mutation can modify an existing gene
in the plant to create a new allele.
Can produce any trait of interest:
morphotype, yielding, resistance/
tolerance to abiotic and biotic,
nutritional quality,..
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Mutation: Mutation is the changes in genetic
material i.e., a random change in gene or
chromosome resulting in new trait(s).
Mutations: 2 types
Spontaneous mutation: Occurs spontaneously in
nature due to environmental effects.
Induced mutation: Induced artificially.
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When mutations are artificially induced
for crop improvement, the entire
operation of the mutation induction and
isolation of desirable mutants is termed
as mutation breeding.
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In short, mutation breeding is
the process to generate
mutants with desirable trait(s).
And compared to conventional
breeding methods, mutation
breeding saves time to develop
a new crop variety.
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From 1930–2015 more than 3,200
mutant varieties have been released
worldwide for commercial use in more
than 210 plant species from over 70
countries.
Bangladesh contributed only 1.4% (as
on 2011).
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1. Objective of the mutation breeding program,
2. Selection of the variety for mutagen treatment,
3. Part of the plant to be treated,
4. Dose of the mutagen,
5. Giving mutagen treatment, and
6. Handling of the mutagen treated population.
PROCEDURE/STEPS FOR MUTATION BREEDING
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A mutation breeding should have a
well defined and clear-cut objective.
1. Objective of the program
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Generally, the variety selected for the
mutagenesis should be the best variety
available in the crop, and has a specific
limitation.
2. Selection of variety for
mutagen treatment
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Mainly seeds are used for
mutagenesis in oilseeds, but pollen
grains can also be used.
3. Part of the plant to be treated
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A dose close to LD50 should be the optimum which
produces maximum mutations and causes minimum
killing.
Normally with sparsely ionizing radiation like X-
ray and Gamma ray the selected dose will cause
30-50% reduction in seedling growth in laboratory
test.
LD50 varies with the crop species and with the
mutagen used.
4. Dose of the mutagen
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5. Giving mutagen treatment
The selected plant parts are exposed to the
desired mutagen dose.
In case of irradiation, dry seeds, bud, rhizome,
cutting or sucker are exposed to the desired
radiation dose and then immediately planted to
raise M1 plants.
Irradiated pollen grains are used for pollination.
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- Seeds are presoaked for a few hours to
initiate metabolic activities and
- Then exposed to the desired concentration of
mutagen and
- Then washed in running tap water for about
four hours to remove the mutagen present in
the seeds.
- The treated seeds are immediately planted in
the field to grow M1 generation.
In case of chemical mutagens-
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1. Inhibition or delaying in germination;
2. Reduction in auxin content;
3. Inhibition of mitosis;
4. Reduction in growth of root and shoot;
5. Decreasing in the number of plant
surviving to maturity;
6. Lower pollen fertility as indicated by
lower or no seed set.
The abnormalities observed in M1
58. Some important characteristics to be
considered during selection
Characteristics for higher seed yield -
Number of plant accommodation per unit area,
Number of pods/capsules per plant,
Number of seeds/capsule or pod, and
1000-seed weight.
59. Characteristics for drought tolerance:
Rapid uptake of soil moisture,
Conservation of water in plant tissues,
Rapid root growth,
Extensive,well developed and deep root system,
High photosynthetic efficiency,
Sensitive stomata to moisture deficit,
Maintenance of high turgor pressure and
Early flowering and early maturity.
60. Characteristics for salinity tolerant lines
Less Na uptake in comparison to K
Less total bio-mass reduction
External symptoms of susceptible lines
Leaf senescence from top to bottom
Sterility of flowers
Reduced root growth
61. Disease resistance:
Ability of a host strain to restrict or
even prevent the production of diseases
symptom by a pathogen.
Disease tolerance:
Ability of a host strain to avoid or
minimize loss in productivity although it
has been infected by a pathogen.
62. Figure: Screening for salinity tolerance, in hydroponic nutrient solution, of rice
mutants at four levels of salt (NaCl2) (0, 5, 10 and 15 dS/m) showing
variation in shoot and root growth after 14 days of applied stress (The
Joint FAO/IAEA Plant Breeding and Genetics (PBGL), Seibersdorf,
protocols 2014). Top row depicting show and lower row for roots.
Courtesy of A. Mukhtar Ali Ghanim.
0 dS/m 5 dS/m 10 dS/m 15 dS/m
62
63. Figure: Screening lentil mutants, in hydroponic solution, for drought
tolerance using PEG6000 at four levels of concentrations (A, B, C and
D), respectively: 0, 10, 15 and 20%. Photos were taken 6 weeks
applying stress pressure protocol optimization experiment at PBGL,
Seibersdorf, Austria in 2014. Courtesy of A Mukhtar Ali Ghanim.
A
D
B
C
63
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Treating seeds with mutagen
M1
i) Mutagen treated M1 seeds are planted
ii) Seeds from individual plant harvested separately
M2
i) Individual plant progenies grown
ii) Plants from rows containing or suspected to contain
the mutant alleles
or
Fertile and normal looking plants harvested separately
M3
i) Selected individual plant progenies grown
ii) Superior lines harvested in bulk, if they are homogenous
iii) In heterogygous progenies, individual plants are selected
lnduced mutation followed by selection
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M4
i) Individual plant progenies from the selected plants grown
ii) Superior homogenous mutant lines harvested in bulk
iii) Segregating lines usually rejected
M5
i) PYT with a suitable check
ii) Superior mutant lines are selected
M6- M8
i) RYT/ ZYT and On-station & On-farm yield trials with a
suitable check at several locations for 2/3 years
ii) Outstanding mutant lines released/registered as varieties
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After completion of the above trials,
application is to be done to the National
Seed Board (NSB) of Ministry of
Agriculture (MoA) for registration as
variety(s) of superior line(s) of non-
notified crops in a prescribed form.
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To
Member secretary,
National Seed Board and Director General (Seed)
Ministry of Agriculture, Bangladesh Secretariat, Dhaka
Name and address of seed dealer (with registration number):
Name of Crop (Botanical name):
Name of crop (English name):
Bengali name of crop:
Name proposed for registration:
Origin of the variety:
Name of breeder:
List the main characteristics of the variety mentioning the
character(s) which make the variety different from other
varieties:
Application form for registration of variety of non-notified crops
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Ecological requirement:
Season:
Soil:
Water:
Any other information:
Cultural requirements:
Method of cultivation:
Seed rate per ha:
Period (in days) from sowing to harvest:
Remarks about susceptibility to disease and insect-
pest:
(a) Results of yield trials:
(b) Yield potential (t/ha):
Signature of Applicant
(Seal)
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Chairman : Additional Director
(Regional office), DAE
Member Secretary: Regional Field Officer
(RFO) of SCA
Members : Representatives of NARS
Institute and DAE
Field Evaluation Team for 5-6 regions
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National Seed Board (NSB)
Chairman : Secretary, MoA
Member Secretary: Director General (Seed),
MoA
Members : DG/Director of NARS
Institutes and DAE and;
Farmer & NGO representatives
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Through transcription : DNA to mRNA
Through translation : mRNA to a polypeptide
chain/protein.
A gene is a segment of DNA &
gene acts by synthesizing protein.
HOW?
In mRNA, there are 4 types of nucleotides namely
Uracil (U), Cytosine (C), Adenine (A) & Guanine (G).
Each group of three nucleotides is responsible for a
particular amino acid.