The F
2 generation of a short-awned mutant and an awnless barley segregated for long-awned types. The cross parents used were: Mutant grsp. 5 of the long-awned barley variety ‘Haisa II’, and the awnless Ethiopian barley ‘Ubamer Baco’. F2-plant progenies in F3 showed that two factors, one a suppressor (S) and (s), and the other an awn-length factor (A′) or (a), control awn length in the cross combination performed. ‘Ubamer Baco’ includes both in the dominant condition (SSA′A′), while the mutant represents the genetic constitution (ssaa). The corresponding genotype of ‘Haisa II’ is (ssAA). In the F2, segregating long-awned types possess the suppressor in the homozygous recessive stage and the awn-length factor either homozygous dominant (ssA′A′) or heterozygous (ssA′a). Together with the recessive suppressor ‘Ubamer Baco’ is long-awned. Modifying factors have an effect on the expression of awn length. Thus genotypes which are identical in the suppressor and the awn-length factor show variability.