Somaclones are obtained by
(a) tissue culture
(b) plant breeding
(d) genetic engineering
(a) Somaclones are obtained by tissue culture. The plant regenerated from cell and tissue cultures shows heritable variation for both qualitative and quantitative traits.
Plant breeding is the branch of Biology, which is concerned with developing varieties superior to existing ones.
Irradiation means exposure to any form of radiation
Genetic engineering is defined as the manipulation of genes by man.