Question

Differentiate between mass selection and pure line selection.

Answer 1

Sr. No.	Aspect	Mass Selection	Pure Line Selection
1.	Meaning	Selection of a number of phenotypically superior plants from a heterogeneous population, harvesting and bulking their seeds to raise the next crop till improvement is achieved.	Developing a variety from a pure line, i.e., progeny of a single self-fertilised homozygous plant, selection involves testing progenies of fewer plants individually.
2.	Genetic Composition	Population remains genetically heterogeneous, based on phenotypic traits in a mixed gene pool.	Results in genetically pure and homozygous varieties, ensuring durability and uniformity.
3.	Applicability	Best suited for cross-pollinated (allogamous) crops with heterozygosity; limited in self-pollinated crops due to low variability.	Mostly used in self-pollinated crops to establish pure lines; also used in cross-pollinated crops during hybridisation for producing pure-line parents.
4.	Basis of Selection	Phenotypic superiority observed in plants or seeds in the field population.	Selection is based on progeny testing of individual plants; fewer plants are selected and tested separately.
5.	Outcome	Improvement through repeated cycles of selection and bulk planting; genetic variability maintained.	Development of genetically stable, uniform, and pure varieties from single homozygous plants.