ABSTRACT
An early, theory of apomixis concerns the wound hormone or necrohormone. The distributions of apomicts were discussed from a biogeographical point of view. Studies of biosystematics and biogeography have thus made it possible to trace pathways of dispersal and possible hibernations during glaciation. These studies have also revealed special genetic systems in connection with apomixis. A. Gustafsson's reviews summarize all earlier work on apomixis in angiosperms. One important type of agamospermy was still unknown at the time of Gustafsson's monograph: apospory of the Panicum type. Allozyme studies with electrophoresis have become an important tool for analyses of genetic variation in both apomictic and sexual populations. Other modern techniques are also useful in studies of both apomictic and sexual plants, for example, embryo culture in wide crosses, various types of tissue culture, cell hybridization, treatment with growth regulators and other compounds. During the 1980s, theoretical and experimental work, in relation to theoretical problems understanding sexual reproduction, expanded.
