This document discusses polyploidy, mutation, and hybridization with reference to medicinal plants. It begins by defining polyploids as organisms with multiple chromosome sets exceeding the diploid number. Polyploids are classified as euploids or aneuploids. Euploids include autopolyploids containing multiple copies of the same genome, and allopolyploids containing genomes from different species. Polyploidy can occur spontaneously or be induced to produce superior plant varieties. The document also discusses mutation, describing types such as point mutations and chromosome mutations. Finally, it defines hybridization as the process of crossing genetically different parents, and describes objectives and types such as inter-varietal and inter

1. Polyploidy, mutation and
hybridization with reference to
medicinal plants
DR. SIDDHI UPADHYAY
H.O.D. & ASSOCIATE PROFESSOR
Dept. of Pharmacognosy and Phytochemistry
SIGMA INSTITUTE OF PHARMACY

2. CONTENT
• Polyploidy with reference to medicinal
plants
• Mutation with reference to medicinal
plants
• Hybridization with reference to medicinal
plants

3. POLYPLOIDY WITH REFERENCE TO
MEDICINAL PLANTS

4. WHAT IS
POLYPLOIDS ?
• Polyploids are organisms with multiple sets
of chromosomes in excess of the diploid
number .
• Polyploidy is common in nature and provides a
major mechanism for adaptation and speciation.
• Approximately 50-70% of angiosperms, which include
many crop plants, have undergone polyploidy during
their evolutionary process.

5. CLASSIFICATION OF
POLYPLOIDS
• based on their chromosomal composition
euploids
aneuploids.
• Euploids constitute the majority of
polyploids.

6. EUPLOI
DY
• are polyploids with multiples of the complete
set of chromosomes specific to a species.
• Depending on the composition of the
genome, euploids can be further classified
into
autopolyploi
ds
allopolyploid

7. AUTOPOLYPLOIDY
• Containing ofmultiple copies of the basic set
(x) of chromosomes of the same genome .
•

8. • occurs in nature through union of
unreduced gametes.
• Natural autoploids include tetraploid crops
such as alfafa, peanut, potato and coffee and
triploid bananas.

9. ALLOPOLYPLOIDY
• A combination of genomes from different species .

10. • They result from hybridization of two or more
genomes followed by chromosome doubling or by
the fusion of unreduced gametes between species
.
• This mechanism is called non-disjunction . These
meiotic aberrances result in plants with reduced
vigor.
• Economically important natural alloploid crops
include strawberry, wheat, oat, upland cotton,
oilseed rape, blueberry and mustard .

11. ANEUPLOIDY
• are polyploids that contain either an addition or
subtraction of one or more specific chromosome(s)
to the total number of chromosomes that usually
make up the ploidy of a species.
•

12. • Aneuploids result from the formation of univalents
and multivalents during meiosis of euploids .
• With no mechanism of dividing univalents equally
among daughter cells during anaphase I, some cells
inherit more genetic material than others .
• Similarly, multivalents such as homologous
chromosomes may fail to separate during meiosis
leading to unequal migration of chromosomes to
opposite poles.

14. EXAMPLES FOR POLYPLOIDS

15. HOW POLYPLOIDS OCCUR?

16. INDUCING POLYPLOIDS…………
• They occur spontaneously through the
process of chromosome doubling.
• Spontaneous chromosome doubling in ornamentals
and forage grasses has led to increased vigour.
• Examples tulip
forage grasses ryegrasses have
yielded superior varieties following spontaneous
chromosome doubling .

17. • breeders have harnessed the process of
chromosome doubling in vitro through induced
polyploidy to produce superior crops.
• For example, induced autotetraploids in the
watermelon crop are used for the production of
seedless triploid hybrids fruits.
• Such polyploids are induced through the treatment
of diploids with mitotic inhibitors such as
dinitroaniles and colchicine .

18. • It is necessary to eliminate duplicated genes in a
newly formed polyploid to avoid gene silencing as
well as to stabilize fertility
• The increase in nuclear ploidy affects the structural
and anatomical characteristics of the plant.
• Polyploidy results in increased leaf and flower
size , stomatal density, cell size and chloroplast
count

19. • Hybrid vigor resulting from interspecific crosses in
allopolyploids is one of the most exploited
advantages of polyploid in plant breeding.
A comparison between the leaf and
flower of a (A) diploid and (B) induced
tetraploid watermelon
A B

20. MUTATION WITH REFERENCE TO
MEDICINAL PLANTS

21. INTRODUCT
ION
• Sudden heritable change in genetic material or character of an organismis
known as mutation
• Individuals showing these changes are known as mutants
• An individual showing an altered phenotype due to mutation are knownas
variant
• Factor or agents causing mutation are known as mutagens
• Mutation which causes changes in base sequence of a gene are knownas
gene mutation or point mutation

22. HISTO
RY
• English farmer Seth Wright recorded case of mutation first time in 1791 in
male lamb with unusual short legs
• The term mutation is coined by Hugo de Vries in 1900 by his observation
in Oenothera
• Systematic study of mutation was started in 1910 when Morgan
genetically analyzed white eye mutant of Drosophila
• H. J. Muller induced mutation in Drosophila by using X- rays in 1927 ; he
was awarded with Nobel prize in 1946

23. CHARACTERISTICS OF
MUTATION
• Generally mutant alleles are recessive to their wild type or normal alleles
• Most mutations have harmful effect, but some mutations are beneficial
• Spontaneous mutations occurs at very low rate
• Some genes shows high rate of mutation such genes are called as mutable
gene
• Highly mutable sites within a gene are known as hotspots.
• Mutation can occur in any tissue/cell (somatic or germinal) of an organism

24. CLASSIFICATION OF
MUTATION
• Based on the survival of an individual
1. Lethal mutation – when mutation causes death of all individuals undergoing
mutation are known as lethal
2. Sub lethal mutation - causes death of 90% individuals
3. Sub vital mutation– such mutation kills less than 90% individuals
4. Vital mutation -when mutation don’t affect the survival of an individual are
known as vital
5. Supervital mutation – This kind of mutation enhances the survival of
individual

25. • Based on causes of mutation
1. Spontaneous mutation-
Spontaneous mutation occurs naturally without any cause. The rate of
spontaneous mutation is very slow eg- Methylation followed by deamination of
cytosine.
Rate of spontaneous mutation is higher in eukaryotes than prokaryotes.
Eg. UV light of sunlight causing mutation in bacteria
2. Induced Mutation-
Mutations produced due to treatment with either a chemical or physical
agent are called induced mutation .
The agents capable of inducing such mutations are known as mutagen.
use of induced mutation for crop improvement program is known as mutation
breeding.
Eg. X- rays causing mutation in cereals

26. • Based on tissue of origin
1. Somatic mutation-
A mutation occurring in somatic cell is called somatic mutation.
In asexually reproducing species somatic mutations transmits
progeny to the next progeny
2. Germinal Mutation-
from one
When mutation occur in gametic cells or reproductive cells are known as
germinal mutation.
In sexually reproductive species only germinal mutation are transmitted to the
next generation

27. • Based on direction of mutation
1.Forward mutation- When mutation occurs from the
normal/wild type allele to mutant allele are known as forward
mutation
2.Reverse mutation- When mutation occurs in reverse direction
that is from mutant allele to the normal/wild type allele are
known as reverse mutation

28. • Type of trait affected
1. Visible mutation- affects on
phenotypic character
Those mutation
and can be
which
detected by normal
observation are known as visible mutation
2. Biochemical mutation- mutation which affect the production
of biochemicals and which does not not show any
phenotypic character are known as biochemical mutation

29. CHROMOSOME
MUTATIONS
• May Involve:
– Changing
the
structure
loss or
gain

30. CHROMOSOME
MUTATIONS
• Five types exist:
–Deletion
–Inversion
–Translocation
–
Nondisjunction
–Duplication

31. DELETI
ON
• Due to breakage
• A piece of a
chromosome is lost

32. INVERSI
ON
• Chromosome segment
breaks off
• Segment flips around
backwards
• Segment reattaches

33. DUPLICAT
ION
• Occurs when a gene sequence is
repeated

34. TRANSLOCA
TION
• Involves two chromosomes that
aren’t homologous
• Part of one chromosome is
transferred to another
chromosomes

35. TRANSLOCA
TION

36. NONDISJUNC
TION
• Failure of chromosomesto
separate duringmeiosis
• Causes gamete to have too many
or too few chromosomes
• Disorders:
– Down Syndrome –
– Turner Syndrome –
– Klinefelter’s Syndrome –

37. CHROMOSOME
MUTATION
ANIMATION

38. TYPES OF GENE MUTATIONS
• Include:
• –Point Mutations
• –Substitutions
• –Insertions
• –Deletions
• –Frameshift

39. POINT
MUTATION
• Change of a single
nucleotide
• Includes the deletion,
insertion, or
substitution of ONE
nucleotide in a gene

40. POINT
MUTATION
• Sickle Cell
disease is the
result of one
nucleotide
substitution
• Occurs in the
hemoglobin gene

41. FRAMESHIFT
MUTATION
• Inserting or deleting one or
more nucleotides
• Changes the “reading frame”
like changing a sentence
• Proteins built incorrectly

42. GENE MUTATION
ANIMATION

43. HYBRIDIZATION WITH REFERENCE
TO MEDICINAL PLANTS

44. MEANING OF
HYBRIDIZATION
• Individual produced as a result of cross between two
genetically different parents is known as hybrid. The natural or
artificial process that results in the formation of hybrid is known
as hybridization.
• The production of a hybrid by crossing two individuals of
unlike genetical constitution is known as hybridization.
Hybridization is an important method of combining characters of
different plants. Hybridization does not change genetic contents
of organisms but it produces new combination of genes.

46. OBJECTIVES OF HYBRIDIZATION
1. To artificially create a variable
population for the selection of types
with desired combination of
characters.
2.To combine the desired characters
into a single individual.
3.To exploit and utilize the hybrid
varieties.

47. TYPESOFHYBRIDISATION
Basing on the taxonomic relationship of two parents, Hybridisation grouped into 2
types
HYBRIDISATION
INTERVARIETAL
HYBRIDISATION
DISTANT
HYBRIDISATION
INTRASPECIF
IC
INTERSPECI
F IC
INTRA
GENERIC
INTER
GENERIC

48. TYPES OF HYBRIDIZATION:
(i) Intra-varietal hybridization:
The crosses are made between the plants of
the same variety.
ii) Inter-varietal or Intraspecific
hybridization:
The crosses are made between the plants
belonging to two different varieties.
(iii) Interspecific hybridization or
intragenric hybridization:
The crosses are made between two different
species of the same genus.

53. Procedure of Hybridization:
It involves the following steps:
(i) Selection of parents.
(ii) Selfing of parents or artificial self-pollinat
(iii) Emasculation.
(iv) Bagging
(v) Tagging
(vi) Crossing
(vii) Harvesting and storing the F, seeds
(viii) Raising the F1 generation.

56. EMASCULAT
ION Baggin
g

58. THANK YOU !!!
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