Question

What is pureline selection? Write procedure, advantages disadvantages and achievements of pure line selection.

Answer 1

Self pollinators: Pure line selection. The progeny of single plant selections are kept separate, not bulked together. The expected result is a set of genetically homogeneous lines. Selection is then imposed on rows (or plots) of the progeny.

Easy and cheap method of crop improvement

Rapid method, lines are usually genetically fixed and yield trials can be immediately conducted.

Plants in such variety react in similar fashion to environmental conditions, means they are uniform in performance and at the same time in appearance too.

Maximum possible improvement over the original variety can be achieved

Useful in improving low heritability traits as selection is based on progeny performance

Disadvantages of Pureline Selection

Demerits of pureline selection are given below:

Purelines have poor adaptability due to narrow genetic base, just opposite to mass selected variety

Superior genotypes can only be isolated from the mixed population. This selection is powerless to bring changes in hereditary factors i.e. to develop new genotype.

Mostly popular or in fact limited to self pollinated spp. only

Time and space consuming

More expensive yield trials have to be conducted than in mass selection

Answer 2

Pure line selection

Explanation:

• Pure Line Selection: In this line selection, an enormous quantity of plants are chosen from a self-pollinated crop and is collected independently, singular plant descendants from them are assessed independently and the best one is discharged as unadulterated line assortment. In this way, it is otherwise called individual plant determination.  

• There are two ways to get uniformity: the clone, and the F1 hybrid.

• Clones are the easiest. Simply breed and select until you have what you want, and then propagate asexually. However, this doesn't work well for most annuals, and then the F1 hybrid (which I didn't work with much) is created using homozygous parents for the characteristics you want when possible to limit variability. Another way to reduce variability is self-pollination, but heterozygous characteristics will exhibit depending on the dominance of the gene or the presence of recessive ones in both parents.

• A simple method is to select for the desired phenotype, cross similar plants, and keep selecting parents for the desired characteristics until the progeny breeds relatively true.