Differences between self-pollination and cross-pollination

March 15, 2018

S.N	Self-pollination	Cross-pollination
1.	Transfer of pollen grains to the stigma of same flower or to the stigma of another flower of the same plant.	Transfer of pollen grains from the anther of a flower to the stigma of another flower borne on a different plant.
2.	Anthers and stigma mature at the same time.	Anthers and stigma mature at different times in a flower.
3.	Usually self pollination does not require any external agency.	It requires external agencies like wind, animals, insects, water.
4.	It gives rise to pure lines after a few generations.	It cannot give pure-lines as it brings about variation.
5.	Less pollen grains are produced.	Pollen grains are produced in huge quantity.
6.	Pollen grains are not wasted.	Pollen grains are wasted.
7.	Plants are less resistant to disease and pests.	Plants are better resistant to disease and pests.
8.	Does not contribute towards evolution.	Important role in evolution.
9.	Lack of variation in characters.	Presence of variation in characters.
10.	Useful characters are preserved.	Useful characters are not preserved.
11.	Harmful characters cannot be eliminated.	Harmful characters can be eliminated.
12.	Yield of the plants fall with time.	Yield of the plants usually increases.
13.	Flowers are neither attractive nor produce nectar.	Flowers attract insects by various means like colored petals, nectar, etc.
14.	It can occur even when the flower is closed.	It cannot occur when the flower is closed.
15.	Produces homozygous off-springs.	Produces heterozygous off-springs.
16.	It takes place in wheat , peas, etc.	It takes place in lady finger, tomato, brinjal, etc.