In this study, 3 visible chimeric cases observed in the M1 generation of fastneutron irradiated durum wheat cultivar, Kunduru-1149, were introduced and possible explanations to their occurence were made in relation to the initial cell numbers, “slicing” effect of fast neutrons and dominant mutations. Considering the chimerism phenomena in M1, dominant mutations should be screened in sectors, i.e. in tillers in cereals, not in the whole M1 plants.