Self incompatibility :
In the self incompatibility plant, the flowers will produce functional or viable pollen grain which fails to fertilize the the same plant or any other flower of the same plant.
• In self incompatibility pollen grains may fail to germinate on the strigmetric surface.
•self incompatibility and estrella tr2 mechanism which encourage cross pollination.
• more than 300 species belonging to twenty families of angiosperm show self-incompatibility.
• in self incompatibility some pollens germinate but fail to penetrate the stigmatic surface.
•some pollen grain main produce pollen tube which enteres through stigmatic surface but its growth will too slow by the time of pollen tube enters the ovule the flower will drop.
•sometimes fertilisation is is affected but improved germinate early.
Classification of self incompatibility:
According to Lewis ( 1954) the self incompatibility is associated as follows.
1. Hetromorphic system
2. Homomorphic system
Also Read 👇👇
Seed Germination
Famous name of crops
Hetromorphic system
In this case there will be difference in the morphology of the flowers.
Such as -
Distyly system
Tristyly system.
Homomorphic system.
In this type of incompatibility is not associated with morphological difference among flowers.
• the incompatibility reaction of Pollen may be controlled by the genotype of the flower.
• it is of two types
1. Sporophytic system
2. gametophytic system
Gametophytic system :
• it was discovered by East and Mangelsdorf in 1925 ine nickatina sanderae .
• in this incompatible reaction of pollen is determined by its own and genotype and not by the genotype of the plant on which Pollen is produced.
• genetically the incompatibility reaction is determined by a single gene having multiple allele.
Saprophytic system :
•this self-incompatibility is governed by a single gene with multiple alleles.
• the incompatibility reaction is determined by the genotype of the plant on which Pollen grain is produce and not by the genotype of the Pollen.
• this system is more complicated, the allele may exhibit dominance and codominance or competition.
It was observed by Hugues and Babcock in 1950 in in Crepis Foetide and by Gerstal in Parthenum argentatum.
• Example : Radish , Brassica,Spinach ....
Thanks.