Reversion of Texas male-sterile cytoplasm maize in culture to give fertile, T-toxin resistant plants.

Plants carrying Texas male-sterile (Tms) cytoplasm are normally sensitive to Drechslera maydis T-toxin. Tissue cultures were initiated from immature embryos of maize carrying Tms-cytoplasm, and plants were regenerated after selection for resistance to T-toxin. Fertile, T-toxin resistant plants were obtained from the unselected control cultures as well as from the selected material. In addition, one regenerant from an unselected culture was fertile and T-toxin sensitive. The progeny of the regenerants showed the phenotype of the female parent with respect to pollen-fertility, and T-toxin resistance. The data are consistent with the heritable changes observed being the result of the expression of an altered mitochondrial genome.