ASEXUAL TRANSMISSION OF CYTOPLASMIC MALE STERILITY

Abstract

Cytoplasmic male sterility in petunia was transferred from cytoplasmic male sterile plants to fertile maintainer plants by grafting. The cytoplasmic factors controlling sterility were subsequently transmitted through seed. Patterns of free amino acids in treated (third generation after grafting) male sterile plants were identical with those in control male sterile plants, indicating that sterility resulted from a transfer of factors across the graft union rather than being induced. This method of transfer parallels that commonly used for transmission of viruses. Thus the phenomenon of cytoplasmic male sterility in petunia may be explained on the basis of virus infection. Under this hypothesis the condition of cytoplasmic male sterility would be analogous to a disease resulting from virus infection.