Factors affecting chemical stimulation of uredospore germination in pustules of crown rust of oats, common corn rust, stem rust of wheat, and leaf rust of wheat

1975 ◽  
Vol 23 (1) ◽  
pp. 4-8 ◽  
Author(s):  
Richard C. French ◽  
Anne W. Gale ◽  
Charles L. Graham ◽  
Howard W. Rines
Keyword(s):  
Leaf Rust ◽  
Stem Rust ◽  
Chemical Stimulation ◽  
Crown Rust ◽  
Factors Affecting ◽  
Stimulation Of

THE EFFECT OF HIGH TEMPERATURE ON UREDIAL DEVELOPMENT IN CEREAL RUSTS

1937 ◽  
Vol 15c (9) ◽  
pp. 425-432 ◽  
Author(s):  
Thorvaldur Johnson ◽  
Margaret Newton
Keyword(s):  
High Temperature ◽  
Leaf Rust ◽  
High Temperatures ◽  
Stem Rust ◽  
Infection Type ◽  
Crown Rust ◽  
Experimental Results ◽  
Wheat Seedlings ◽  
Physiologic Races ◽  
Cereal Rusts

The effect of high temperatures on the development of stem rust and leaf rust on wheat seedlings and stem rust and crown rust on oats seedlings was studied in greenhouse experiments. The experimental results show that, for temperatures above the optimum for rust development, the higher the temperature the less vigorous the pustule development. Physiologic races that at ordinary temperatures produce a "4" type of infection tend to develop a "3" type or an "x" type at higher temperatures. At still higher temperatures the infection type becomes "2" or "1" or even merely necrotic flecks. Physiologic races of the same rust differ in their sensitiveness to temperature. In stem rust of wheat, races that had been inbred by repeated selfings for two or more generations, showed greater sensitiveness to temperature than races collected in the field. Leaf rust of wheat and crown rust of oats were less tolerant of high temperatures than stem rust of wheat.

SEEDLING REACTIONS OF WHEAT VARIETIES TO STEM RUST AND LEAF RUST AND OF OAT VARIETIES TO STEM RUST AND CROWN RUST

1940 ◽  
Vol 18c (10) ◽  
pp. 489-506 ◽  
Author(s):  
Margaret Newton ◽  
T. Johnson ◽  
B. Peturson
Keyword(s):  
High Temperature ◽  
Leaf Rust ◽  
East Africa ◽  
High Resistance ◽  
Stem Rust ◽  
Crown Rust ◽  
Seedling Stage ◽  
Wheat Varieties ◽  
The Cross ◽  
Physiologic Races

A study of the rust reactions of wheat varieties to 20 physiologic races of stem rust has shown that several varieties of the vulgare type, namely, McMurachy, Eureka, and several strains from Kenya, East Africa, are immune in the seedling stage at ordinary greenhouse temperatures (55° F. to 80° F. daily). This immunity largely disappears when the plants are kept at a constant high temperature (75° F. to 80° F.). Certain other varieties and hybrid strains were found rather highly resistant to eight physiologic races of leaf rust, but none of the vulgare varieties tested showed immunity or high resistance to both stem rust and leaf rust.Tests to determine the resistance of oat varieties to the physiologic races of oat stem rust and crown rust prevalent in Canada showed that four oat varieties derived from the cross Hajira × Joanette were resistant to all the physiologic races of oat stem rust used in the test, and that certain strains derived from the cross Victoria × (Hajira × Banner Sel. 524) were resistant to all but one of these races. The last mentioned strains and the varieties Victoria and Trispernia proved resistant to the nine races of crown rust to which they were tested.

Cereal rust control in Canada

2007 ◽  
Vol 58 (6) ◽  
pp. 639 ◽  
Author(s):  
B. D. McCallum ◽  
T. Fetch ◽  
J. Chong
Keyword(s):  
Leaf Rust ◽  
Stripe Rust ◽  
Resistance Genes ◽  
Stem Rust ◽  
Rust Resistance ◽  
Stem Rust Resistance ◽  
Crown Rust ◽  
Economic Losses ◽  
Puccinia Graminis ◽  
Highly Effective

The major cereal crops grown in Canada are wheat (11 Mha), barley (4 Mha), and oat (1.5 Mha). Over 90% of the total cereal production area is in the western provinces of Manitoba, Saskatchewan,and Alberta. Historically, the disease of major concern in wheat was stem rust, caused by Puccinia graminis f. sp. tritici. The first significant stem rust resistant cultivar in Canada was Thatcher, grown extensively from 1939 until the early 1970s. The stem rust resistance in Thatcher was relatively effective, with the exception of susceptibility to race 15B epidemic in the 1950s. Thatcher, however, was very susceptible to leaf rust, caused by Puccinia triticina. Over time, improved resistance to both stem and leaf rust was achieved with the release of cultivars with additional genes for resistance, primarily Sr2, Sr6, Sr7a, Sr9b, Lr13, Lr14a, Lr16, and Lr34. Over the years genetic resistance has adequately controlled stem rust but leaf rust continues to cause significant losses, partially due to changes in the P. triticina population which reduced the effectiveness of resistance genes such as Lr13 and Lr16. Stripe rust on wheat, caused by Puccinia striiformis f. sp. tritici, was historically a problem under irrigation in southern Alberta, but since 2000 it has been found annually in the central Canadian prairies and southern Ontario. The genetic basis of resistance to stripe rust in most Canadian wheat cultivars has not been determined, although Yr18 provides partial resistance in many cultivars. In contrast to wheat, rust diseases have generally not caused concern for barley producers. Stem rust, caused by P. graminis f. sp. tritici, is the primary concern for barley growers, and has been controlled through use of gene Rpg1 since 1947. In 1988 race QCCJ with virulence on Rpg1 was detected in the prairie region but to date has not caused significant economic losses in barley. The resistance gene rpg4 is effective against QCCJ, but no commercial varieties have yet been produced with rpg4. In oat, both stem rust, caused by Puccinia graminis f. sp. avenae, and crown rust, caused by Puccinia coronata f. sp. avenae, have caused significant yield losses. Both rusts have been controlled mainly through host resistance and early planting. Stem rust resistance genes Pg2 and Pg13 have been the most effective and occur in many current oat cultivars. However, in 1998, 2 races, NA67 and NA76, with virulence on both Pg2 and Pg13 were detected in the prairie region. Currently, race NA67 is predominant in the prairie region and thus all Canadian cultivars are susceptible to stem rust. Since the 1980s, improved resistance to crown rust has been achieved through use of resistance derived from Avena sterilis. Pc39 was the first of the genes derived from this wild relative to be deployed in a new cultivar, followed by the release of cultivars possessing both Pc38 and Pc39. These 2 genes remained effective until the early 1990s. From 1994 onward, a series of cultivars with the highly effective Pc68 gene introgressed from A. sterilis were released. Virulence to Pc68 appeared in 2001, and in 2005 cultivars with this gene were severely rusted. The cultivar Leggett with Pc68 plus the highly effective Pc94 gene from the diploid A. strigosa was released in 2004. Rhamnus cathartica, the alternate host of P. coronata, is widespread in Canada and removal of these woody shrubs in the vicinity of oat fields is important to reduce the severity of crown rust. The increased use of fungicides on all cereals in the past 10 years has been fairly effective in rust control but represents an added input cost for producers.

Chemical Stimulation of the Brain Makes Stimulating Reading

1975 ◽  
Vol 20 (12) ◽  
pp. 923-924
Author(s):  
MADGE E. SCHEIBEL ◽  
ARNOLD B. SCHEIBEL
Keyword(s):  
Chemical Stimulation ◽  
The Brain ◽  
Stimulation Of

scholarly journals Incidence and Distribution of Puccinia coronata and P. graminis on Turfgrass in the Midwestern United States

Plant Disease ◽  
2018 ◽  
Vol 102 (5) ◽  
pp. 955-963
Author(s):  
Brijesh B. Karakkat ◽  
Vonte L. Jackson ◽  
Paul L. Koch
Keyword(s):  
United States ◽  
Stem Rust ◽  
Kentucky Bluegrass ◽  
The United States ◽  
Primary Objective ◽  
Crown Rust ◽  
Puccinia Coronata ◽  
Midwestern United States ◽  
Fungal Populations ◽  
Relationship Of

Crown rust (caused by Puccinia coronata) and stem rust (caused by P. graminis) are two common and destructive diseases of turfgrass in the United States. Crown rust has been associated with perennial ryegrass and stem rust with Kentucky bluegrass when identified based solely on fungal morphology. However, recent studies using molecular identification methods have indicated the host–pathogen relationship of rusts on turf to be more complex. Our primary objective was to quickly and accurately identify P. coronata and P. graminis in symptomatic turfgrass leaves over 3 years on turfgrass samples from across the Midwestern United States. Between 2013 and 2015, 413 samples of symptomatic cool-season turfgrass from Wisconsin and surrounding states were screened using real-time polymerase chain reaction. Of these samples, 396 were Kentucky bluegrass and 17% of them contained P. coronata, 69% contained P. graminis, and 13% contained both P. coronata and P. graminis. In addition, both year and location effects were observed on the distribution of Puccinia spp. collected annually from two locations in southern Wisconsin. This research supports previous conclusions that have identified variability among P. graminis and P. coronata host relationships on turfgrass, and further demonstrates that rust fungal populations on Kentucky bluegrass may not be consistent between locations in the same year or over multiple years at the same location. The increasing evidence of variation in the turfgrass rust populations will likely affect future rust management and turfgrass breeding efforts.

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