Which of the following is the best method for directly utilizing the available variability in self-pollinated crops:

Correct option is B

Pure line selection focuses on isolating and propagating superior lines from within an existing population. It doesn't introduce new variability.

Other Options:

Option A: Domestication: Domestication is the initial process of adapting wild plants for human use. While it increases variability over the long term, it's not the best method for directly utilizing existing variability.

Option C: Pedigree Method: The Pedigree Method is a breeding technique used to develop new varieties by crossing selected parents and tracking their progeny. It relies on existing variability within the breeding population.

Option D: Introduction involves bringing in a new variety of a self-pollinated crop from a different region or country.
This introduces new genetic variability that can be directly utilized for breeding and improvement.