somaclonal variation can be obtained by

1. application of colchinies
2. irradiation with gamma rays
3. tissue culture
4. hybridisation

Somaclonal variationis the variation seen in plants that have been produced byplant tissue culture.Chromosomalrearrangements are an important source of this variation.
Somaclonal variation is not restricted to, but is particularly common in, plants regenerated fromcallus. The variations can begenotypicorphenotypic, which in the latter case can be either genetic orepigeneticin origin. Typical genetic alterations are: changes in chromosome numbers (polyploidyandaneuploidy), chromosome structure (translocations, deletions,insertionsandduplications) and DNA sequence (base mutations). A typical epigenetics-related event would begene methylation.