Abstract
By the modified method of mutagenic MNUA treatment consisting in a short interincubation germination, a very high frequency of point mutations was obtained in many varieties and stocks of spring barley. In the obtained collection of dwarf and semidwarf mutants a rich variability of many traits not connected with the plant height was noted. Mutations concerned the productivity of the plants, their tillering, the length and width of leaves, the habitus, distribution of leaves on the stalk and the morphology of the ear. The diversity of forms described in the collection of dwarf and semidwarf mutants characterises MNUA as a mutagen inducing a very high frequency of mutations in initial cells.