PURE LINE SELECTION
A pure line is the progeny of a single, homozygous, self-pollinated plant. In pure line selection, a large number of plants are selected from a self-pollinated crop and are harvested individually; individual plant progenies from than are evaluated, and the best progeny is released as pureline variety.
Therefore, pureline selection is also known as individual plant selection. A pureline variety is a variety obtained from a single homozygous plant of a self-pollinated crop.
CHARACTERISTIC OF PURE LINES
- All the plants within a pureline have the same genotype as the plant from which the pureline was derived.
- The variation within a pureline is environment and non-heritable.
- Purelines become genetically variable with time. The genetic variation is produced by mechanical mixtures, natural hybridization or mutation.
Merits of pureline selection
- Pureline selection achieves the maximum possible improvement over the original variety. This is because the variety is the best pureline present in the population.
- Pureline varieties are extremely uniform since all the plants in the variety have the same genotype. Such a uniform variety is more liked by the farmers and the consumers than a less uniform variety developed through mass selection.
- Due to its extreme uniformity the variety is easily identified in seed certification programmes.
Demerits of pure line selection
- The varieties developed through pureline selection generally do not have wide adaptation and stability in production possessed by the local varieties from which they are developed.
- The procedure of pureline selection requires more line space and more expensive yield trials than mass selection.
- The upper limit on improvement is set by the genetic variation present in the original population.
- The breeder has to devote more time to pureline selection than o mass selection. This leaves less time for other breeding programmes.