How can one use the law of homological series in the hereditary variation of N. I. Vavilov in selection practice.

The law of homological series of hereditary variation of N.I. Vavilov. The first most serious study of mutations was the work of N.I. Vavilov on establishing parallelism in hereditary variability in plant species belonging to close taxa.
Based on extensive studies of the morphology of various plant species, Vavilov in 1920 came to the conclusion that, despite the pronounced diversity (polymophism) of many species, a number of patterns in their variability can be noted. If we take the family of cereals as an example and consider the variation of some characteristics, it turns out that the same deviations are inherent in all species.
Vavilov’s law states: “Species and genera that are genetically close are characterized by similar series of hereditary variation with such correctness that, knowing a number of forms within the same species, it is possible to predict the presence of parallel forms in other species and genera. The closer genes are genetically located in the general system of genera and linneons, that is, species, the more complete the similarity in the ranks of their variability. “