Selection of Mutants Showing Partial Resistance To Powdery Mildew (Erysiphe Graminis DC.F.SP. Hordei Marchal) in Barley (Hordeum Vulgare L.) After Sodium Azide Mutagenesis*

After sodium azide treatment of seeds of the 2-rowed spring barley variety ‘Bomi’ with medium levels of resistance, 558 M1 spike progenies (7532 M2 plants) were screened for the selection of mutants showing changed reaction to mildew infection. Selected spike progenies were screened in the M2 and the mildew reaction confirmed in the M4 generation. Selection occurred in two parallel experiments, one in greenhouse and one in field. Forty three mutants corresponding to a mutation rate of 7.7% on M1 spike basis and 0.6% on M2 plant basis were obtained, Inspite of the different selection conditions, the number as well as the spectrum of mildew mutations were similar in the two experiments. Six agronomic characters of the mutants were studied in the M4 generation. Three partial resistant mutants did not differ significantly from ‘Bomi’ in any of the characters, and 9 mutants differed in one character only. Inheritance of 11 mildew and 83 leaf colour mutants was studied by M2 segregation analysis. Only 7% of the leaf colour mutants showed deviation from the expected 3:1 segregation ratio.