an inbred homozygous strain (C. D. Darlington & K. Mather, The elements of genetics, 1949, London, Allen & Unwin). `An assemblage of sexually reproducing individuals of uniform appearance propagated by seeds or spores, its stability maintained by selection to a standard ` (Cult. Code, Art. I lb). isolate. a subdivision of a physiologic race (E. C. Stakman & D. M. Stewart, Memorandum regarding taxonomy of physiologic races of Puccinia graminis var. tritici, 1957), e.g. physiologic race l5B-(line) l. In plant pathology the term should be used only in the sense of (2), as applying to host plants.