Erwin Baur or Carl Correns: Who really created the theory of plastid inheritance?

Historical reviews of the field of non-Mendelian genetics and many other pu blications credit Erwin Baur and Carl Correns equally for the development o f the theory of plastid inheritance. However, a study of the original liter ature indicates that this conclusion is not correct. Analysis of the releva nt articles leads to the conclusion that Baur alone deserves credit for the theory of plastid inheritance, In his classic article on the inheritance p roperties of white-margined Pelargonium plants, Baur (1909) stated: (1) The plastids are carriers of hereditary factors which are able to mutate. (2) In variegated plants, random sorting-out of plastids is taking place, (3) T he genetic results indicate a biparental inheritance of plastids by egg cel ls and sperm cells in Pelargonium. By contrast, Correns held the view that in variegated plants there is a maternally transmitted labile state of the cytoplasm which switches either to a permanently "healthy" state (allowing the "indifferent" plastids to become green chloroplasts) or to a permanentl y "diseased, ill" cytoplasmic state (causing white plastids and cells). Ott o Renner supported Baur's theory and worked out important characteristics o f plastid inheritance in the genus Oenothera. In the 1930s Renner reported many more observations, which established plastid inheritance as a widely a ccepted genetic theory.