a group of organisms occurring in nature and assumed to be genetically almost identical (Johannsen, 1903 quoted by C. D. Darlington and K.Mather, The elements of genetics, 1949, London, Allen & Unwin); a population of genetically identical individuals (E. C. Stakman & J. G. Harrar, Principles of plant pathology, 1957, New York, Ronald Press Co. A sub- division of a species, subspecies or serotype which may be distinguished from other subdivisions of the species by the possession of some special or usefully diagnostic physiological character ` (Bact. Code, Rec. 8a (2) annot.). a sub- division of a physiologic race; a sub-race.
A group of individuals in nature, all with essentially the same genetic constitution. A species consists of several biotypes. A group of individuals with the same genotype. Biotypes may be homozygous or heterozygous.