Albugo occidentalis Albugo occidentalis Albugo occidentalis, the causal agent of Spinach White Rust, is an oomycete plant pathogen, although some discussions still treat it as a fungal organism. "Albugo occidentalis" is one of the most important spinach diseases in North America, found throughout the United States east of the rocky mountains. The economically important host of "Albugo occidentalis" is spinach (Spinacia oleracea); although the oomycete has also been reported to affect plants of the genus Chenopodium, the genus including the crop plant quinoa. This pathogen causes white rust or white blister of spinach. It is unrelated to the basidiomycete rusts biologically, but
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