Induced mutations and barley improvement.

Seven barley varieties, originating from three X-ray induced mutations, have been officially approved in Sweden since 1958. Some have gained a wide area of cultivation. The list is as follows: Pallas, isolated 1947, approved 1958, mutant ert-k (32) of Bonus barley. - Mari, isolated 1950, approved 1960, mutant mat-a (8) of Bonus. - Hellas, approved 1967, mutant cross of Pallas × Herta. - Kristina, approved 1969, mutant cross of Domen × Mari. - Visir, approved 1970, Pallas × Long Glumes back-crossed to Pallas. - Mona, approved 1970, mutant cross of Mari × Monte Cristo back-crossed to Mari. - Gunilla, approved 1970, hybrid cross of the mutant 44/3 arisen from Gull barley in 1939; evolved in a series of steps, using one six-row and four two-row varieties, with mutant characters prevailing and Gull genes reiterated. - After the first approval of Pallas in 1958, 12 more years have led to the approval of a second mutant case and five mutant crosses. In addition, chromosome translocations, induced by irradiation in Bonus, have been instrumental in the production of hybrid barley in USA and are used in the barley improvement program of Sweden, as well as for theoretical analysis in numerous countries.