Male sterility in plants: occurrence, determinism, significance and use

Most of higher plant species are hermaphroditic and male-sterility is often considered as an accident of development. In fact among the multiple possi ble causes of male-sterility, the most frequently met in nature is cytoplas mic male-sterility (cms) which is a maternally inherited trait playing an a ctive role in the evolution of gynodioecious species. Recent molecular stud ies have shown that this trait is determined by additional genes created in plant mitochondrial genomes due to their high recombinogenic activity. The physiological mechanisms by which the products of these genes interfere wi th the formation of male gametophytes are still the subject of intense rese arch. (C) 2001 Academie des sciences/Editions scientifiques et medicales El sevier SAS.