Nature and Mechanisms of Cytoplasmic Male Sterility in Plants: a Review1

Abstract

Cytoplasmic male sterility (CMS) has been described in many of our cultivated crops and is commercially useful in the production of hybrids when pollen vectors will provide the necessary economic levels of seed production. In the more common type, the sporophytic, the development of the microspore is affected by the abnormal growth of the tapetum or mistiming of callose formation and, in corn at least, the mitochondrial complex is involved. In the gametophytic system the factor causing abortion of the pollen apparently resides in the microspore rather than in its environment. Other systems which suggest plasmid-like inclusions associated with CMS have been reported. Transfer to the cytosterile mechanism by cell fusion has been accomplished, but wider application of this technique waits on methods for development of plants from naked protoplasts In more species.