EMS‐Induced Male‐Sterile Mutants in Euplasmic and Alloplasmic Common Wheat¹

We studied 12 EMS‐induced male‐sterile mutants that were isolated from alloplasmic Triticum aestivum L. having T. tauschii (Coss.) Schmal. cytoplasm. Of these 12, four mutants had all empty pollen grains; the remaining eight mutants had small proportions of fertile pollen grains. Eleven of the male‐sterile lines were crossed to euplasmic ‘Chris’, and the F 1 heterozygous male‐fertile plants were selfed or used as males in backcrosses to Chris. The BC 1 S 1 male‐fertile plants were used as males in backcrosses to alloplasmic male‐sterile Chris to observe segregation for male‐sterility. Segregations in F 1 , F 2 , and BC 1 S 1 progenies indicated that the inheritance of male‐sterility in the 11 mutants was controlled by single recessive genes, three of which were shown to be allelic. Eight of these mutant genes induced male‐sterility in euplasmic T. aestivum , and the same capability for the other three recessive mutants was not ruled out. One of the 12 mutants, FS6, had a dominant gene controlling male‐sterility. This dominant male‐sterile (FS6) produced segregating F 1 's from crosses with four common wheat cultivars and seven male‐fertility restorer (R‐)lines containing Rf genes from T. speltoides (Tausch) Gren. ex Richter, T. monococcum L., or 4x or 6x T. timopheevii (Zhuk.) Zhuk. The results indicated that the dominant gene for male‐sterility in FS6 was stable under different genetic backgrounds and did not interact with other gene(s) affecting male fertility.