Comparative Analyses of Some of the Free Amino Acids in Anthers of Fertile and Genetic Cytoplasmic Male Sterile Sorghum.

ENETIC cytoplasmic male sterility in Sorghum is fundamentally an aspect of the problem of gene action and nuclear-cytoplasmic interaction. Our interest in the problem stems not from a concern with the practical use so effectively being made of the failure of certain lines to produce functional pollen but rather from a desire to know more about the basic components of this process as an example of gene-cytoplasm relationships. Moreover, while studies for the better understanding of the biochemical correlates of genetic expression have been conducted extensively in bacteria, viruses, and fungi, which admittedly present better material for such research, need is felt for more information about comparable processes in the higher plants. Such studies are not new, but it was thought that cytoplasmic male sterility offered a somewhat unique situation in which such studies, combined with the possibilities of investigating nuclearcytoplasmic interaction, might be carried on. Since the initial work of MAUNDER and PICKETT (1959), it has been considered that genetic cytoplasmic male sterile lines in Sorghum carry the recessive genes (ms ms) for male sterility. This, however, is not the only factor involved since other lines with the same gene complement are functional pollen producers. The difference between the two lines resides in the cytoplasm, the first line carrying some factor or factors for sterility, or lacking factors for fertility, the second line possessing such fertility factors or lacking those for sterility. In addition to having such isogenic lines differing only in cytoplasm, fertility restorer lines are available which carry the dominant form ( M s ) of the male sterile gene or genes (MAUNDER 1960). Genetic cytoplasmic male sterility could presumably be the result of a relatively simple cause-a deficiency of one or more organic compounds. This deficiency might reflect the nonfunctioning of an enzyme system and result in subsequent accumulation of certain metabolites. Such accumulations might be expected to result if recessive gene action is visualized as inhibiting normal enzyme activity. Both the fertile and sterile lines dealt with in this study carry a recessive gene for male sterility and comparisons are therefore indicated between these lines and the fertility restorer lines. Although critical analyses of