Dr Swaminathan has set up a well-known school of research in the field of radiation genetics and mutation research at the Institute. His original contributions (1948-58) include elucidation of the origin of potato, dwarf coconut and bread wheat, nuclear cytology of yeasts, classification and genetics of polyploid plants, monosomic analysis in wheat, elucidation of the role of infection in heredity, relationship between chromosome associations and seed fertility in autopolyploids and standardization of techniques for overcoming interspecific incompatibility barriers. His later contributions (1959-64) relate to experimental manipulation of genes in a purposeful direction. This work has involved the introduction, selection and hybridization of a wide range of dwarf material by wheat containing the "Norin" dwarfing genes from Mexico and the use of a wide array of mutagens, both physical (X-rays, gamma-rays, fast and thermal neutrons, and beta particles) and chemical (alkylating agents and free radicals).