Development of B‐Lines for Two Cytoplasmically Controlled Male Sterilities of Cotton 1

One form of male sterility in cotton, Gossypium hirsutum L., depends upon the interaction of nuclear and cytoplasmic factors. Maintenance of such lines is difficult, but is facilitated by using B‐lines as male parents. Blines have the same nuclear factors as cytoplasmicallp male‐sterile lines, but lack the “male‐sterile” cytoplasm. Test crosses of such B‐lines with homozygous male sterile stocks with “pollen‐sterile” cytoplasm gave progenies with pollen sterility equal to, or greater than, those obtained from self pollination of the cytoplasmically male sterile cottons in question.