Question

Differentiate between mass selection and pure line selection.

Answer 1

The process in which plants having desirable characteristics are selectively propagated, thus eliminating the undesirable characteristics is known as selection. It is one of the most important techniques involved in plant breeding.

Complete answer:
Selection and breeding of a progeny obtained from superior organisms for several generations to attain a pure line of organisms having desired characters only is known as a pure line section while mass selection involves collection of seeds from individual plants showing the desirable characteristics. The seeds from the next generation are then allowed to grow from stores of mixed seeds.

Following are the major differences between mass selection and pure line selection:

Mass Selection	Pure line selection
Mixture of pure lines is obtained.	Pure line is obtained.
To maintain the purity, mass selection needs to be repeated every year.	Once formed, pure lines can easily be maintained.
It is carried out in both self-pollinated as well as cross pollinated plants.	It is carried out only in self-pollinated plants.
The variety obtained has high adaptability and stability.	The variety obtained has narrow adaptability and stability.
Variety obtained depicts variable characteristics.	Variety obtained depicts uniform characteristics.
During the seed certification, new varieties cannot be easily identified.	During the seed certification, new varieties can be easily identified.
It shows heterozygous.	It shows homozygosity.
Pollination control not required.	Pollination control is necessarily required so as to allow plants to self-pollinate only.

Note: Both the selection procedure namely, mass selection as well as pure line selection exhibits selective breeding only. They are aimed at improving the crop plants. They typically belong to an artificial mode of selection involving the clonal selection.