Law of parallel variation was given by

Solution (By Examveda Team)

The Law of parallel variation was given by Vavilov.
It was given by Vavilov in 1920 and was published in the Journal of Genetics in 1922.
This law established a parallel variability of homologous characters in taxonomically near species. Now it must be extended, including also a parallel variability of similar homologous characters in taxonomically remote species.