Search results
Results from the WOW.Com Content Network
The fungal ancestors of stem rust have infected grasses for millions of years and wheat crops for as long as they have been grown. [7] According to Jim Peterson, professor of wheat breeding and genetics at Oregon State University, "Stem rust destroyed more than 20% of U.S. wheat crops several times between 1917 and 1935, and losses reached 9% twice in the 1950s," with the last U.S. outbreak in ...
P. graminis (stem rust of wheat and Kentucky bluegrass, or black rust of cereals); primary hosts include: Kentucky bluegrass, barley, and wheat; Common barberry is the alternate host. Heteroecious and macrocyclic; P. hemerocallidis (daylily rust); daylily is primary host; Patrinia sp is alternate host. Heteroecious and macrocyclic
Cronartium ribicola (White pine blister rust): the primary host are white pines, and currants the secondary. Hemileia vastatrix (Coffee rust): the primary host is coffee plant, and the alternate host is unknown. Puccinia graminis (Stem rust): the primary hosts include Kentucky bluegrass, barley, and wheat; barberry is the alternate host.
Other cereal rust fungi have macrocyclic, heteroecious life cycles, involving five spore stages and two phylogenetically unrelated hosts. P. striiformis was thought to be microcyclic for centuries until 2009, when a team of scientists at the USDA-ARS Cereal Disease Lab led by Yue Jin confirmed that barberry (Berberis and Mahonia spp.) is an alternate host. [3]
Wheat rusts include three types of Pucciniae: P. triticina , wheat leaf rust , leaf rust, wheat brown rust, or brown rust P. graminis , stem rust , wheat stem rust, barley stem rust, or black rust
Gerbner's model of communication starts with the perception of an event. M is the communicator who formulates a message about this event. The message is then perceived and interpreted by the audience, labeled in the diagram as M₂. [138] The relation between message and reality is of central importance to Gerbner.
The Puccinia species causing wheat leaf rust has been called by at least six different names since 1882, when G. Winter (1882) described the Puccinia rubigo-vera. [5] During this time, wheat leaf rust was interpreted as a specialized form of P. rubigo-vera. Later, Eriksson and Henning (1894) classified the fungi as P. dispersa f.sp. tritici.
The steps of encoding and decoding in Schramm's model perform the same role as transmitter and receiver in the Shannon–Weaver model. [5] [23] [24] Because of its emphasis on communication as a circular process, the main focus of Schramm's model is on the behavior of senders and receivers. For this reason, it does not involve a detailed ...