What is self compatibility?, Stages of SI, types of SI and their explanation has been covered in detail with pictures.

1. STUDENT
MAYURIKKA T.P
CB.AG.U4AGR19137
COURSE TEACHER
DR.DHIVYAPRIYA
ASST.PROFFESOR(GENETICS
AND PLANT BREEDING)
AMRITA SCHOOL OF AGRICULTURAL
SCIENCES
(AMRITA VISHWA VIDYAPEETHAM)
ARASAMPALAYAM, COIMBATORE
SELF INCOMPATIBILITY IN PLANTS

2. SELF INCOMPATIBILITY(SI)
 It refers to the inability of a plant with
functional pollen to set seeds when self
pollinated. It is the failure of pollen from a
flower to fertilize the same flower or other
flowers of the same plant

3.  The term ‘Self incompatibility’ was coined by
STOUT in 1917

4.  Self incompatibility was reported in
Verbascum phoeniceum by KOELREUTER

5. STAGES OF SI
failure to germinate failure to penetrate
at stigmatic surface stigma
si
slow growth of
pollen tube embryo degenerate

7. BASED ON FLOWER
MORPHOLOGY
HETEROMORPHIC SYSTEM
SI is associated with difference in flower
morphology
i. Distyly
ii. Tristyly

8. Distyly
 Styles and stamens are of two types i.e, short
and long
 Here only S gene is involved.
 Found in Pin and Thrum flowers of Primula

11. Tristyly
 Styles and stamens are of three types i.e,
short,medium and long.
 Here two genes are involved (S and M)
 Found in Lathyrum salicaria

15. HOMOMORPHIC SYSTEM
The flowers do not differ in morphology.
i. Sporophytic
ii. Gametophytic

16. GAMETOPHYTIC SYSTEM
 East and Mangelsdorf (1925) in Nicotiana
sandreae
 Incompatibility reaction is determined by the
genotype of pollen.
 Single genes with multiple alleles with
codominance effects
 E.g, Potato,Tomato,Rye.

17.  Partially compatible or completely
compatible or incompatible in the case of
gametophytic system.

18. The single S allele determines pollination. If the S allele matches
either of the genotype of female alleles ,there is no germination

19. SPOROPHYTIC SYSTEM
 Hughes and Babock(1950) in Crepis foetida
(stinking hawsbeard)
 Gersel(1950) in Parthenium
 Incompatibility is determined by the genotype
of the plant and not by the genotype of pollen.
 Controlled by S gene with multiple alleles
 E.g., Radish, Brassica, Spinach and Sunflower

20.  No partial fertilization.
 Either 100% complete fertilization or 100%
incomplete fertilization.
S1>S2>S3>S4

21. If the S alleleof any pollengrainmatches the female ,no pollination.

23. GENES INVOLVED
 MONOALLELIC
SI controlled by a single gene
 DIALLELIC
SI controlled by two genes
 POLYALLELIC
SI controlled by several genes

24. SITE OF GENE EXPRESSION
 STIGMATIC
SI is expressed on stigma
E.g, Radish,Cabbage,Cauiliflower,
Linum grandiflorum
 STYLAR
SI expressed on style
E.g, Bouganvillea,Helianthus

25.  OVARIAN
SI is expressed on ovary
E.g., Lilium, Cocoa,Gasteria(ox tongue/cow
tongue /lawyer tongue)

26. POLLEN CYTOLOGY
 BINUCLEATE
Pollen grain have 2 nuclei
 TRINUCLEATE
Pollen grain have 3 nuclei

27. Application of SI in plant breeding
 Sporophytic incompatibility is widely used in
breeding of cabbage and other Brassica
species.
 Single cross hybrids are more uniform and
easy to produce.
 Combining desirable genes

28. REFERENCE
 www.biologydiscussion.com
 www.biology-pages.info
 http://www.britannica.com