DNA Heterogeneity Within the C Group of Maize Male‐Sterile Cytoplasms1

Restriction endonuclease fragment analyses of organelle DNAs from five members of the C group of male‐sterile maize ( Zea mays L.) cytoplasms revealed three mitochondrial DNA types, while no chloroplast DNA variation was observed. It is proposed that three subgroups of the C group be designated: CI (C cytoplasm); CII (RB, BB, and E cytoplasms); CIII (ES cytoplasm). Heterogeneity within the C group indicates the possibility of broadening the cytoplasmic base of hybrid maize production.