Self-pollination and its type

  • Self-pollination is the transference of pollen grains from the anther of a flower to the stigma of either the same or genetically similar flower.
  • It is generally not dependent on any external agency for pollination.
  • It is of two types:


  • It is the transfer of pollen grains from anther of a bisexual flower to its stigma.
  • Both stamens and carpels mature at the same time.
  • It occurs in several cereals (wheat, rice), some peas and flower which do not open.


  • It is kind of self-pollination where flowers could be bisexual or unisexual but are borne by the same parent plant.
  • The pollens from one flower deposited on the stigma of another flower borne on the same plant.
  • It may require an external agency like insects or wind.
  • Self-pollination may occurs when the flowers are open (chasmogamy) or closed (cleistogamy).
  • Chasmogamous self-pollination occurs only when their anthers and stigma mature at the same time (homogamy).
  • The self-pollinated flowers are generally small, inconspicuous, colourless, odourless, and nectarless.
  • Self-pollination occurs by following methods:


Image result for types of self pollination


a) Homogamy

  • In this case the anthers and stigmas of a bisexual flower mature simultaneously.
  • The pollen grains reach the mature stigma either by contact, wind, gravity, rain drop or even insects.
  • Self-pollination brought about by contact is called direct autogamy and remaining agencies perform indirect autogamy.

i) Direct autogamy

  • It is accomplished by the movement of floral parts on account of growth, bending or folding.
  • In Convolvulus, Ixoza, Catharanthus and Gardenia the anthers are borne at the mouth of the corolla tube.
  • With the growth of style the stigma comes in contact with the ripe anthers and pollination occurs.
  • Pollination takes place in Cotton when the stigma in being pushed out of the staminal tube due to the growth of the style.
  • In Mirabilis, the filaments of ripe anthers bend and bring in contact with stigma.
  • A similar curling of style takes place in potato.
  • The stigma of Sunflower has brushing hair which helps in pushing the pollen grains from the synantherous tube.
  • The stigma curls back and receives the pollen grains present on the brushing hair.
  • The closing of flowers at night performs self-pollination in Argemone mexicana.

ii) Indirect autogamy

  • It occurs without coming contact of anthers and stigmas.
  • The pollen grains reach the stigma by rain (e.g. Caltha) or gravity (e.g. Lilac).
  • In Lilac, the anthers lie exactly above the stigmas.
  • The pollen grains of the dehisced anthers fall over the low lying stigmas under the influence of gravity.
  • In Sanicula, male and female flowers grow side by side.
  • The long style of the female flower bends over the male flowers to get pollinated.

b) Cleistogamy

  • It occurs in bisexual flowers which are always closed.
  • Such closed flowers can perform only self- pollination.
  • It is generally accompanied by geocarpy when the fruits are formed underground, e.g. Groundnut.
  • The phenomenon of having both open and closed flowers is called chasmocleistogamy.

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Advantages of Self-pollination

  • It does not depend on the external agency, so it is a sure method of pollination.
  • Some flowers e.g. Oxalis utilize self-pollination for seed production when cross-pollination fails. Pollen grains are not wasted.
  • Parental characters can be preserved by this pollination.
  • It causes no genetic variations and because of this property, it maintains the purity of the races from generation to generation.
  • It is utilized in production of homozygous parents for experimental hybridization and evolving useful varieties.

Disadvantages of Self-pollination

  • It produces weak progenies, generation after generation, which cannot adapt to the changing environment.
  • It does not help in evolution of new species, as it does not cause any variability.
  • It cannot give any new character or new ability to the plant.
  • Useful characters cannot be introduced by this method.
  • The undesirable and defect characters do not get eliminated from a plant.
  • The immunity of race towards infection decreases. Thus, the plants become susceptible to many diseases.