Presentations for aspiring Biology students

2. Man is absolutely dependant on plants, they are one
of the most important factors which influence human
life.
Introduction
Apart from food, plants also provide clothing, fuels,
drugs, construction materials etc.
There will remain a never ending demand for food
as the population is growing & will continue to grow.
Advance method of plant breeding needs to be
adopted to increase the production.
PLANT BREEDING is an applied branch of botany
which involves collective use of art & science for
changing & improving the heredity of plants to create
desired types.

3. Plants should be better suited for cultivation.
Aims of Plant Breeding
They should give better yield & should be disease
resistant.
The quality of the plants should improve & also
ability to tolerate environmental stress.
The plants should be resistant to pathogens & pests.
Specific agronomic characters like dwarfness,
intensive branching, reduction in dormancy etc
should be developed.

4. Collection of variability.
Five Steps in Plant Breeding
Evaluation & selection of Parents.
Cross hybridisation among the selected parents
Selection & Selfing of superior recombinants
Testing, commercialization & release.

5. STEP I : Collection of variability.
Collection & preservation of the different wild
varieties , species & relatives of crops is done.
All such collected genes are effectively exploited
The entire collection having all the diverse alleles
for all the genes in a particular crop is called as
germ-plasm collection.
Germ plasm is evaluated to identify plants with
desirable characters
STEP II : Evaluation & selection of Parents.
Such selected plants are used in process of
hybridization. Pure lines are created wherever
desirable & possible.

6. STEP III : Hybridisation among the selected parents
Crossing of desired plants is done to combine useful
characters.
Hybridization also helps in exploiting & utilising the
hybrid vigour (heterosis – superiority over either parent in one or more characters)
Steps in Hybridisation
One plant has to be used as a female plant, If such a
plant has bisexual flowers emasculation is done.
Emasculated flowers are covered by butter paper
bags to prevent pollination from unwanted pollen --
bagging.
Emasculation (removal of stamens) is done by various
methods like Hot water method /Forcep method.

7. Mature pollen collected from selected male plant are
dusted on receptive stigma, flowers are re-bagged &
fruits are allowed to develop.
Generally one in few hundred to a thousand crosses,
the hybrids formed show desirable combination of
characters.
Steps in Hybridisation contd…..
STEP IV: Selection & Selfing of superior recombinants
Plants superior to both the parents & exhibit hybrid
vigour are collected.
They are selfed for homozygosity due to which the
plant attains uniformity & characters do not
separate.

8. STEP V : Testing, commercialization & release.
Newly selected lines are evaluated in controlled
conditions, then grown in natural fields for 3
growing seasons in different agro-climatic zones.
These testings are carried out by expert agencies
like ICAR (Indian Council for Agricultural Research)
GREEN REVOLUTION – At a glance
The development of many improved high yielding
varieties of crops (1970-80) through the techniques of
plant breeding attained record production.
This was popularly termed as green revolution

9. Some High Yielding Crops
1960 to 2000
Wheat 11 million
tons
75 million
tons
Sonalika & Kalyansona
Other high yielding Wheat: Sonora 65, Lerma Rojo 64-A, Safed Lerma, Sharbati Sonora
Rice 35 million
tons
89.5 million
tons
Jaya & Ratna (derivatives of
IR 8 & Taichung native I)
Other high yielding Rice : Vijaya, Padma, Kanti & Jayanti
Note: All are semi-dwarf varieties of developed by (International centre for
Wheat improvement – Mexico & IRRI (Rice) – Philipines & Taiwan)
Saccharum
barberi
North
India
Poor yield Co.421, Co. 419,
Co.205, Co. 453,
Co. 740 –
Coimbatore better
varieties
Saccharum
officinarium
South
India
High sugar content & better yield
but susceptible to diseases

10. Plant Breeding for Disease resistance
Resistance to disease is a genetically controlled
character, hence it can be transferred to weak crops.
Production of disease resistant varieties is cheapest,
effective & convenient as compared to other
physical/chemical/biological methods to prevent
diseases
This method not only enhances food production but
also reduces the dependence on chemical pesticides.
It is carried out by conventional breeding techniques
of hybridization & selection or mutation breeding.

11. Methods of Plant Breeding for Disease resistance
Mutation is defined as sudden & heritable variations
which appears in organisms due to permanent
change in their genotype.
Mutations can be induced artificially through
chemical/physical factors called mutagens.
Mutants with desirable characters are selected.
Induction of mutation & utilisation in developing
desirable traits in an organism is called as
mutational breeding.
Moong beans resistant to yellow mosaic virus &
powdery mildew has been develped.

12. Causative Agent Name of the Disease
Virus Tobacco mosaic, turnip mosaic
Bacteria Black rot of Crucifers
Fungi Brown rust of wheat, Red rot of Sugarcane
Late blight of potato
Plant bred for Disease resistance
Name Disease
Himgiri (Wheat) Hill bunt leaf & Stipe rust
Pusa shubhra (Cauliflower) Curl blight black rot &
Black rot
Pusa snowball K1(Cauliflower)
Pusa sadabahar (Chilli) Leaf curl, Chilli mosaic virus

13. Plant Breeding for Insect pest resistance
Naturally occuring Hairy leaves in Cotton resistant
to Jassids, smooth leaved nectar less Cotton ressitant
to Boll worms.
Maize with high Aspartic acid & low N2, sugar are
resistant to maize stem borers.
Pusa Gaurav – resistant to Aphids
Pusa Sawni & Pusa A-4 – resistant to shoot & fruit
borers have been developed.

14. Biofortification
It is the method of breeding plants for good
nutritional value.
It focuses on making food more nutritious as the
nutrients are developed in the plant during its
growth rather than the nutrients being added during
processing.
There are two main methods namely;
Selective breeding & Genetic modification.
It is cheap, major efforts are in Brazil, India &
China.

15. Selective Breeding (IARI Delhi)
Varieties with high nutritious content are bred to
achieve crops with greater nutritious content.
Hybrid Maize with double the quantity of amino
acids like Lysine, Tryptophan have been developed.
Wheat variety (Atlas - 66) with high protein content
has been used for improving cultivated wheat.
Rice with five times more Iron has been developed.
Vitamin A enriched Carrots, Spinach, Pumpkin
Vitamin C enriched Bitter gourd, Bathua, Mustard,
Tomato
Calcium enriched Spinach , protein enriched beans
& Garden Pea have been developed.

16. Genetic modification
Golden Rice is the GM food which is rich in beta-
carotene.
Genes for beta-carotene have been inserted from soil
bacterium Erwinia /maize/daffodils.
Beta-carotene (Provitamin A) can be converted into
Vitamin A in human body.
The inserted genes produce enzymes required to
synthesize beta-carotene.
Increasing the micronutrient level in staple food
prevents the micronutrient deficiencies in rural area.
Staple food is commonly consumed in rural areas.

17. Growing or rearing cells on artificial medium in
aseptic conditions is called as tissue culture.
Tissue Culture
TERMINOLOGIES & REQUIREMENTS
Explant – the plant material used for tissue culture
(meristematic or parenchymatous tissue).
Totipotency – it is the property of cells to divide &
differentiate in to an entire plant.
Callus is a group of un-organised & undifferentiated
mass of cells.
Tissue culture is of two types namely.
Callus Culture Suspension Culture

18. Morphogenesis / Organogenesis:
It is the process of development of different organs
from callus.
Clones:
Genetically identical organisms are clones.
Callus Culture:
Nutrient medium is in semi-solid state.
Suspension Culture:
Nutrient medium is in liquid state.
TERMINOLOGIES & REQUIREMENTS contd…

19. Nutrient Medium
Sterilisation
It contains various ratios & concentrations of Organic
& Inorganic nutrients, certain vitamins, sucrose,
hormones.
pH is adjusted at about 5-5.8, agar-agar a
polysaccharide (derived red alga) is added for semi-
solid/solid consistency
Apparatus, medium, explant are sterilized to avoid
contamination
Apparatus is sterilized by dry/wet sterilization, explant
is treated with 1% Sodium hypochloride, 70%
alcohol/10% Hydrogen peroxide

20. Methodology
1. Explant culture
2. Callus formation & culture
3. Organogenesis
4. Formation of cell/suspension culture
Applications
1. Micropropogation
2. Production of disease free plants
3. Production of secondary metabolites
4. Somatic hybridization

22. Single Cell Protein
1. It refers to any biomass produced by
uni/multicellular microbes, & can be used as
food/feed additives.
2. Chlorella, Spirulina, Methylophilus methylotoropus
– Yield Proteins.
3. Spirulina grows on waste water frompotato
processing units, straw, molasses, animal manure.
4. It can be done throughout the yearvery effectively
in smaller area
5. A 250 kg cow produces200 gm of proteins per day
whereas Methylophilus methylotropus of same qty
produces 25 tonnes of proteins