hybrid seed production by using self incompatibility

1. CENTURION UNIVERSITY OF TECHNOLOGY AND MANAGEMENT
M.S.SWAMINATHAN SCHOOL OF AGRICULTURE
SUBMITTED BY :
Name : J.Cherishma.
reg .no : 180804280012.
section : D.
Semester : 6th semester.
Guided by : Dr.Niranjan kumar chaurasia.

2. Topic : Application of self incompatibility in hybrid seed production
Self incompatibility introduction
• Why self incompatibility ?
• Why hybrids ?
Self incompatibility in hybrid seed production .
• Steps involved in hybrid seed production .
• How to maintain homozygous SI inbreds ?
• Crosses used to produce f1 hybrids.
• Characters should be possessed by superior self incompatible lines for hybrid
seed production.
Advantages and limitations .
Achievements .
Conclusions and future prospects.

3. • Inability of plant to set seeds with functional pollen after self pollination .
• Koelreuter -1st reported S.I in Verbascum phoeniceum plants(18th century )
• Self incompatibility reported in about 70 family of angiosperm including several crop
spp.
• It is important for outbreeding mechanism(cross pollination) for normal fruit set.
• It maintained high degree of heterozygosity and can take place any stage between
pollination and fertilization.
• Self incompatible pollen grain may fail to germinate on the stigmatic surface.
• Some may germinate but fails to penetrate the stigmatic surface.
• Some pollen grains may produce pollen tube, which enters through stigmatic surface,
but its growth will be too slow. By the time the pollen tube enters the ovule the flower
will drop.
• Some time fertilization is effected but embryo degenerates early.
Self incompatibility

4. self incompatibility classification

5. Heteromorphic self incompatibility
tristyly
distyly

6. gametophytic self incompatibility sporophytic self incompatibility
This was reported by east & Mangelsdorf in nicotiana
sanderae in 1925 .
This was given by hughes & babcock (1950) in crepis
foetida and grestel in parthenium (1950)
The stigma is smooth and wet The stigma is papillate and dry.
Pollen tube inhibition in style Pollen tube inhibition take place on stigmatic surface
itself.
Genetic constituents of gametes control si. Genetic constituent of pollen producing plant
controls si.
Sterile ,partial sterile and fertile crosses obtained. Either fertile or sterile crosses obtained.
It is governed by single gene S with multiple alleles
,the alleles have individual action without any
interaction.
Governed by single gene S with multiple alleles , the
alleles show dominance or independent reaction as
for their allelic combination involved (mostly
dominant reaction). [s1>s2>s3>s4 :-dominance ].
Plants belonging to this type have binucleate pollen. Plant belonging to this type have trinucleate pollen.

7. Gametophytic self incompatibility
Sporophytic self incompatibility

8. why self incompatibility ?
• Production of F 1 seeds at large scale.
• Reduced cost of labour for hybrid seed production.
• Speedup the hybridization programme .
• Used for commercial exploitation of hybrid vigour .
why hybrids preferred by farmers ?
• Greater productivity
• Longer harvest duration
• Better adaptability to variable
environments

9. • Better tolerance to diseases and pests
• Uniform produce
• Better market acceptability
• Better nutritional quality

10. Self incompatibility in hybrid seed production
Steps involve in hybrid seed production
Identification of self-incompatible plants in diverse
population/genotypes
 Development of homozygous self-incompatible lines
Identification of S-alleles in the homozygous self-incompatible lines
Establishment of inter-allelic relationships among the S-alleles
Identifying the best combining lines
 Maintenance of parental self-incompatible lines
Commercial hybrid seed production

11. How to maintain homozygous SI inbreds
o Bud pollination / Sibmating
o Treatment with CO 2 gas (CO 2 enrichment) or sodium
chloride .
o Tissue culture using meristem
o Sodium chloride sprays
o Removal of stigmatic surface or whole stigma, useful in
sporophytic system.
o Exposure to high temperature.
o Double pollination

12. • Stable self incompatibility.
• High seed set of self pollination at bud
stage.
• Favorable and uniform economic
characters.
• Desirable combination ability.

13. Seed production program of hybrids
> Selected field should be
free from volunteer crops.
> In order to maintain seed
genetic purity isolation
distance should be
maintained by preventing
cross pollination
• Mantaining female
parents to male plants
ratio in hybrid seed
production plot.
• Seed inspection should
be done to check
isolation distance ,off
types ,planting ratio.
In order to have high purity
seed utmost care should
be taken during harvesting
• First male plants are
harvested followed by
female plant .
• Threshing should be
done separately in dry
floor.
Selection of
field
Isolation.
Planting ratio
Nicking
Field
inspection.
Harvesting
,threshing.

14. Crosses used to produce f1 hybrids
SINGLE CROSS HYBRIDS : it is a cross between 2 inbreds is known as single cross
hybrids . It gives maximum heterosis and produce uniform plants .also helps in
predicting the performances of double cross hybrids.
A × B
F1
 DOUBLE CROSS HYBRIDS : it is given by jones .it is a cross between two single cross
hybrids .
A × B C × D
F1 × F1
F1

15.  TRIPLE CROSS HYBRIDS : it is a cross between two three way cross hybrids ( three way cross hybrid is
a cross between single cross hybrid and inbred line ).
A × B C × D
F1 × C’ F1 × C’’
F1 × F1
F1
ADVANTAGES OF SELF INCOMPATIBILITY :
Production of hybrids.
Combining desirable genes.
Multiplication of inbred lines.
Creation of variability.

16. Testing the combining ability.
Reduce the cost of hybridization .
Hybrid seed production without emasculation ,CMS,GMS.
Limitations :
Production and maintenance of homozygous inbred lines is difficult.
 cost of hybrid seed production.
Environmental factors sometimes reduce or totally overcome self incompatibility.
Pseudo-incompatibility.
Hybrid seeds would be expensive if the self incompatible lines are difficult are difficult
to maintain.
There is a limited use of SI due to problems associated with the maintenance of
inbred lines through hand emasculation as it is tedious and costly.

17. Achievements
Crop Name of hybrid type of genetic
mechanism
(parentage)
Developing institution
Cabbage KGMR-1,BRH-5 (KGMR-1=83-1-
621×GA-111 )
IARI regional station ,
katrain
cabbage H-43,H-44 (H-43=S2S2× Pusa
Mukta)
(H-44=S2S2 × cornell
83-6 )
IARI regional station ,
katrain.
cauliflower Pusa hybrid-2 , pusa
kartik sankar
(pusa Hybrid-2=CC×
18-19)
(Pusa kartik sankar
=CC14× 41-5 )
IARI ,new Delhi.
cauliflower Xiahua6 (heat
resistant )
Self incompatibility X lamen agricultural
research institute of
sciences ,china,2006
• The study of SI in crucifer crops began in Japan, where it still continues. In 1949, a Chinese cabbage F 1 hybrid
variety, " Nagaoka Kohai I Go", was produced by Shojiro Ito, and in 1961 a radish F 1 hybrid variety, " Harumaki
Minowase ", was produced by a commercial seed company.

18. • Pollination control mechanism is helpful for making the hybrid seed
production profitable by reducing cost.
• self incompatibility is becoming increasingly important for hybrid seed
production in vegetables crops.
• Highly self incompatible lines are available in radish and cauliflower for its
commercial utilization in hybrid seed production .
• SI is affected by environmental factors such as temperature and humidity
,which reduces or break down of incompatibility at high temperature.
• For hybrid seed production we have to select stable incompatible parent
inbred lines.
Conclusion :-

19. Future prospects
• To fulfill the demand of vegetables in our country, develop more of hybrid
varieties for higher yield.
• To identify the stable SI and CMS lines
• There is need to acquire deeper knowledge about these two important
mechanisms for developing location/ environmental specific SI and MS lines
• Produce transgenic sterility or incompatibility in the crops in which it is not
present
• Exploit the mechanism in the crops identified.

20. Thankyou