Scandinavian mutation research in barley - a historical review.

In 1928, the Swedish geneticists Hermann Nilsson-Ehle and Åke Gustafsson started on their suggestion experiments with induced mutations using the barley crop. In 1953, at the instigation of the Swedish Government, the 'Group for Theoretical and Applied Mutation Research' was established. Its aim was to study basic research problems in order to influence and improve methods for breeding cultivated plants. The research was non-commercial, even if some mutants were of practical importance. The peaks of activities occurred during the 1950s, 1960s and 1970s. Applying X-rays and UV-irradiation very soon the first chlorophyll mutations were obtained followed by the first viable mutations 'Erectoides'. Soon the X-ray experiments expanded with other types of irradiation such as neutrons etc. and finally with chemical mutagens, starting with mustard gas and concluding with the sodium azide. The research brought a wealth of observations of general biological importance, high increased mutation frequencies, difference in the mutation spectrum and to direct mutagenesis for specific genes. A rather large collection of morphological and physiological mutations, about 12 000 different mutant alleles, with a very broad variation were collected and incorporated into the Nordic Genetic Resource Center (NordGen) Sweden. Barley, the main experimental crop has become one of the few higher plants in which biochemical genetics and molecular biological studies are now feasible. The collection is an outstanding material for mapping genes and investigating the barley genome. Several characters have been studied and analyzed in more detail and are presented in this historical review.