Abstract
When seeds and vegetative tissues are irradiated, a competition occurs in meristematic tissues between lethally and sublethally affected cells on one hand and unaffected cells on the other hand to the advantage of the latter. This phenomenon was first recognized by Freisleben and Lein (1943) and termed intrasomatic selection by Kaplan (1951) and diplontic selection by Gaul (1957). The work done on the nature of this phenomenon in seed-propagated plants is summarized along with suggested methods to reduce its intensity.