Male sterility refers to the failure of plants to produce functional pollen or male gametes. There are several types of male sterility including genetic, cytoplasmic, and chemically-induced male sterility. Genetic male sterility is governed by recessive genes and can be temperature or photoperiod sensitive. Cytoplasmic male sterility is controlled by the mitochondrial genome and is not influenced by the environment. Cytoplasmic-genetic male sterility involves both nuclear and mitochondrial genes and is the most widely used system for commercial hybrid seed production in crops like maize, rice, and wheat.

1. Male Sterility
Sanjay Kumar Bishnoi
Ph. D. ResearchScholar
SKRAU, Bikaner

2. What is Male Sterility???
 Male sterility is defined as “the failure of plants to produce
functional anthers, pollen, or male gametes .”(Kaul,1988)
History:-
• First time reported by Kolreuter (1763) in maize.
• Beedle (1932) and Roger (1953) - CGMS in maize
• Rhodes (1933) - CMS in maize
• Jones and Davis (1944) - CMS in onion

4. Male fertile and sterile lines
Anther is full of pollens
(deep purple/blue
after iodine stain)
Anther is withered,
and has no pollen in it
Male Fertile
Male Sterile

5. Some important terms
A-line or Male Sterile
line
B-line or maintainer
line
R-line or restorer line
msms
rr
msms
Rr
msms F/S
RR
msms S
msms F

6. Classification of Male sterility
1. Genetic male sterility (GMS)
i) Temperature sensitive genetic male sterility (TGMS)
ii) Photoperiod sensitive genetic male sterility (PGMS)
iii) Transgenic male sterility (TrGMS)
2. Cytoplasmic male sterility (CMS)
3. Cytoplasmic genetic male sterility (CGMS)
4. Chemically induced male sterility (CIMS)

7. 1. GENETIC MALE STERILITY
• Governed by a single recessive gene ‘ms’.
• The ratio of sterile and fertile plants is 1:1
• This method is used for both seed and vegetatively
propagated crops for hybrid seed production.
• It is influenced by environment factors.
ms ms × Ms Ms
(male sterile) (Male fertile)
F1 Ms ms (male fertile)
F2 1 Ms Ms, 2 Ms ms, 1 ms ms
3 Male fertile 1 Male sterile
Ratio 3:1

8. i) Temperature sensitive genetic male sterility (TGMS)
In this type of GMS complete male sterility is produced by the ms gene at
higher temperature 23.3⁰C.
ii) Photoperiod sensitive genetic male sterility (PGMS)
In this type of GMS complete male sterility is produced by the ms gene
between 23-29⁰C temperature at higher photoperiod > 14 hours (long day).
>14 hours = Plants male sterile
< 14 hours= Plants male fertile
iii) Transgenic male sterility (TrGMS)
A gene introduced into the genome of an organism by recombinant DNA
technology or genetic engineering is called transgene.
Eg. Barnase/ Barstar system (Bar gene of Bacillus amyloliquefaciens)
Barnase = Male sterile
Barstar = Male fertile
Application of Genetic Male Sterility in Plant Breeding
Applicable in production of hybrids in both vegetatively propagated crops and
crops important for fruit or seed yield.
eg. Castor = USA
Pigeon pea = India (variety released- ICPH-8, 1991)

9. 2. CYTOPLASMIC MALE STERILITY
• Controlled by plasma gene contributed by female parent. (Mitochondrial
DNA, Cp DNA and Plasmid)
• This method is using only in vegetative propagated crops.
• It is highly stable i.e. not influenced by environmental factors.
Genotypes of CMS line
– With normal fertile cytoplasm
(B – line; fertile)
– With sterile cytoplasm
(A – line; sterile)
msms F
R / r
msms S
R / r

10. Sterility maintenance
msms Smsms F
R / r
A – line
(sterile)
B – line
(fertile)
All male sterile
progenies
msms S
R / r
X R / r
Application of Cytoplasmic Male Sterility in Plant Breeding
Production of hybrids in ornamental crops and vegetatively propagated crops,
where grain or fruit is not the economic product.
Examples – Ornamental plants, potato, onion etc.

11. 3. CYTOPLASMIC – GENETIC MALE STERILITY
• Controlled by induction of both nuclear and plasma genes.
• First reported by Jones & Esweller (1937) in onion.
• 1944 – Jones first found ‘S’ type from USDA stock
and Roger in Texas found ‘T’ type
• The fertility restorer gene Rf, is dominant.
A-line or Male Sterile line
B-line or maintainer line
R-line or restorer line

12. Male Sterility Maintenance
Fertility Restoration
msms S
rr
msms S
Rr
msms S
RR
msms S
rr
msms F
rr
msms S
rr
msms F
RR
Male sterile
(A – line)
All fertile
progenies
A – line
(sterile)
B – line
(Fertile)
All male
sterile
progenies
or
Male fertile (R – line)
X
X

13. Application of Cytoplasmic-Genetic Male Sterility
in Plant Breeding
• CGMS is most popular MS system for commercial
utilization due to inherent disadvantages of GMS and
CMS.
• It is used in commercial production of hybrid seeds
maize, sorghum, bajra, sunflower, rice and wheat.

14. 4. Chemically induced male sterility (CIMS)
Many chemicals affect the function of male reproductive organs in plants,
these compounds called chemical hybridizing agents (CHA) or male
gametocide.

15. Crop Cytoplasm Restore genes Remarks
1. Maize (Z.m.) Cms – C
Cms – S
Cms – T
Rf4
Rf3
Rf1, Rf2
Spontaneous reversion
Commercially used
• Most commercially used
• Reduce yield (2-4%)
• Susc. To southern corn blight
& sheath blight
Sorghum
(S.bicolor)
Milo
(S.bicolor)
MSc (one) Commercially used
Bajra
(Penmisteum
americanum)
Tifton (P. amc.)
Ludhiana (P. anc)
A1
A2
Commercially used
Little used
 Most well studied CMS system in crop plants
 A number of cytoplasms known in maize :
- Texas (T)
- USDA (S)
- Charrua (C)
- Normal (N)
- NA (North America)