1. Male sterility & its
significance in plant
breeding
Submitted by:- Sweety Dahiya
Class:- M.Sc. (P) Botany
Roll no. 31

2. Contents
• Introduction
• Manifestations of male sterility
• More prevalent than female sterility
• Classification
• Genetic male sterility
• Cytoplasmic male sterility in Maize
• Fertility restoration in Maize
• Chemically induced male sterility
• Applications
• Significance in plant breeding
• References

3. Introduction
• Male sterility:- it is the failure of plants
to produce functional anthers, pollen,
or male gametes.
• Occurs mainly in bisexual plants.
• J.K. Koelreuter (1763) observed anther
abortion within species & species
hybrids.
• More prevalent than female sterility.

4. • Absence or malformation of male organs.
• Failure to develop normal microsporogenous tissue-
anther
• Abnormal microsporogenesis deformed or inviable pollen
• Abnormal pollen maturation
• Non dehiscent anthers but viable pollen, sporophytic
control
• Barriers other than incompatibility preventing pollen from
reaching ovule

5. • Male sporophyte and gametophyte less
protected from environment than ovule and
embryo sac
• Easy to detect male sterility, because a large
number of pollen for study available
• Easy to assay male sterility:-
 Staining technique (caramine, lactophenol or
iodine)
 Female sterility requires crossing
• Male sterility has propagation potential in
nature

6. Phenotypic
• Three types of sterility:
• “Pollen sterility” in which male sterile individuals
differ from normal only in the absence or extreme
scarcity of functional pollen grains (the most
common and the only one that has played a major
role in plant breeding)
• “Structural or staminal male sterility” in which
male flowers or stamen are malformed and non
functional or completely absent
• “Functional male sterility” in which perfectly
good and viable pollen is trapped in indehiscent
anther and thus prevented from functioning

7.  Cytoplasmic male sterility (CMS) - sterile cytoplasm
(S)
• Male sterility comes about as a result of the combined action
of nuclear genes and genic or structural changes in the
cytoplasmic organellar genome.
• maternally inherited.
 Nuclear male sterility (NMS) - Genic, genetic,
mendelian
• Male sterility is governed solely by one or more
nuclear genes.
• Nuclear inherited
 Non genetic, chemically induced male sterility-
• Application of specific chemical (gametocides or chemical
hybridizing agents)

8. Genetic male sterility
• Controlled by a
number of nuclear
genes- MALE
STERILE GENES.
• Effectiveness of
these genes maybe
expressed by-
 %age of viable
pollens.
 %age of seed set.
• GMS is controlled by
a pair of recessive
alleles “msms”.

9. Flower phenotypes in carrot
• a) Normal (N-cytoplasm, restored CMS plants)
• b) Brown anther CMS
• c) Petaloid CMS

10. • Male & female reproductive organs are
present on different parts of the plant.
• In 1930s, Rhoades demonstrated that
male sterility in Maize can be caused
by maternally inherited factor.
• Rhoades pollinated the ears of male
sterile strain with the pollen from a
male fertile strain.

11. .

12. Fertility restoration in Maize

13. .

14. Chemically induced male
sterility
• It can be done when different growth
hormones such as NAA, IAA, Malic
hydrazide etc are sprayed on plants
before flowering.
e.g Cotton, Wheat, Sorghum etc.
• But it is not possible to obtain
complete male sterility by using
chemicals.

15. • Eliminate emasculation in
hybridization.
• Increase natural cross-pollination in
self pollinated species.
• Controlled pollination by Maize plants.
• Facilitate commercial hybrid
reproduction.

16. Significance of male sterility in
plant breeding
• Hybrid production requires a female plant
in which no viable gametes are borne.
Emasculation is done to make a plant
devoid of pollen so that it is made female.
• Genetic male sterility is used in hybrid
seed production but has limitations due
to the need to maintain female parent
lines as hetrozygotes & segregation of
fertile & sterile plants each generation.

17. • Singh, B.D. (1998): Biotechnology, Kalyani
Publishers, New Delhi.
• Snustad, P. and Simmons, M.J. 2003. Principles
of Genetics. (2nd edition). John Wiley , New York.
• http://link.springer.com/article/10.1007%2FBF00029958
• http://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&frm=1
&source=web&cd=6&ved=0CFcQFjAF&url=http%3A%2F%2
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jKA&bvm=bv.63808443,d.aGc
• http://www.google.co.in/url?sa=t&rct=j&q=&esrc=s&frm=1
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2Fwww.sementi.it%2Finformazione%2Fdownload%2Fmate
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