Rust (fungus) an autoecious fungus which can complete its life cycle on a single host species. Understanding the life cycles of rust fungi allows for proper disease management. There are definite patterns of relationship with host plant groups and the rust fungi that parasitize them. Some genera of rust fungi, especially "Puccinia" and "Uromyces", comprise species that are capable of parasitizing plants of many families. Other rust genera appear to be restricted to certain plant groups. Host restriction may, in heteroecious species, apply to both phases of life cycle or to only one phase. The fungi produce asexual spores which disperse by
True-breeding organism plants for gardeners are F1 hybrids, which if propagated from seed will produce F2 hydrids which are quite different from their parents; the F1 hybrids therefore don't breed true. True-breeding organism A true-breeding organism, sometimes also called a purebred, is an organism that always passes down certain phenotypic traits (i.e. physically expressed traits) to its offspring of many generations. An organism is referred to as true breeding for each trait to which this applies, and the term "true-breeding" is also used to describe individual genetic traits. In Mendelian genetics, this means that an organism must be homozygous for every trait