Competitive ability of oat stem rust races in mixtures

1973 ◽  
Vol 51 (11) ◽  
pp. 2233-2236 ◽  
Author(s):  
J. W. Martens
Keyword(s):  
Stem Rust ◽  
Competitive Ability ◽  
Field Conditions ◽  
Puccinia Graminis ◽  
Number Of Genes ◽  
Physiologic Races

Mixtures of races of oat stem rust (Puccinia graminis Pers. f. sp. avenae Eriks. and E. Henn.), differing in virulence, were cultured on susceptible plants in growth cabinets for five uredial generations at 15, 20, and 25 °C and in the field. The races with fewest genes for virulence maintained or increased their levels in the growth cabinets in all cases but were consistently outperformed by races with more genes for virulence under field conditions. The field results are in general agreement with the course of evolution of physiologic races of oat stem rust in Canada over 50 years; they suggest that the number of genes for virulence carried by a given race, other than those required for successful parasitism, is probably not the key determinant affecting its success in nature.

PHYSIOLOGIC SPECIALIZATION OF OAT STEM RUST IN CANADA

1944 ◽  
Vol 22c (5) ◽  
pp. 201-216 ◽  
Author(s):  
Margaret Newton ◽  
T. Johnson
Keyword(s):  
Stem Rust ◽  
Wide Distribution ◽  
Puccinia Graminis ◽  
Characteristic Type ◽  
Influence Of Temperature ◽  
Physiologic Specialization ◽  
Influence Of Temperature On ◽  
Physiologic Races

An account is given of the results of studies on the physiologic specialization of Puccinia graminis Avenae Erikss. and Henn. in Canada since the inception of the work. Twelve physiologic races were identified from 2586 isolates studied during the period 1921 to 1943. The annual surveys of the prevalence of physiologic races during this period show that each year races 1, 2, and 5 have comprised the bulk of the oat stem rust in all parts of Canada. The predominance of these races has been greatest in the three Prairie Provinces, where barberry is virtually non-existent. In regions where barberry is present, other races of greater range of pathogenicity have been found more frequently than in these three provinces. The occurrence of such races, however, was sporadic until 1943, in which year races 8, 10, and 11 attained a wide distribution, apparently traceable to wind-borne urediospores from the south. There is evidence that the strains of these races present in 1943 remain in the uredial stage for much longer periods than do strains of the same races collected in previous years—a fact that may have favoured their spread in this year.The role of barberry in the origination of generally virulent physiologic races is discussed. The possibility that such races may also originate by mutation is suggested by spontaneous pathogenic changes that occurred, in the greenhouse, in a culture of race 3 that gave rise to several cultures of race 7.The effect of environment on the identification of physiologic races is demonstrated by the seasonal influences on the reaction of the variety Sevnothree to races 1 and 11. On this variety the characteristic type 1 is frequently replaced, in summer, by type x.Experiments on the influence of temperature on the reaction of adult oat plants to stem rust showed that a constant temperature of about 80° F. does not appreciably affect the reaction of White Tartar and Richland, or of other varieties with the same type of resistance, but is capable of breaking down the resistance of certain varieties derived from the crosses Hajira × Joanette, Hajira × Banner, and Victoria × (Hajira × Banner).

THE SOURCE OF RESISTANCE AND THE INHERITANCE OF REACTION TO 12 PHYSIOLOGIC RACES OF STEM RUST, PUCCINIA GRAMINIS AVENAE (ERIKSS. AND HENN.)

1951 ◽  
Vol 29 (3) ◽  
pp. 189-205 ◽  
Author(s):  
J. N. Welsh ◽  
T. Johnson
Keyword(s):  
United States ◽  
Stem Rust ◽  
Adult Stage ◽  
The United States ◽  
Puccinia Graminis ◽  
Probable Explanation ◽  
Main Gene ◽  
Physiologic Races

Resistance to 12 races of oat stem rust was unexpectedly obtained from three crosses, Hajira–Jostrain, Hajira–Richland, and Hajira–Banner, between the years 1932 and 1940. Recent investigations have shown that the Hajira parent was the source of this resistance, as 10% of plants selected from this variety were found to be highly resistant. Inheritance studies have shown that, in some crosses involving this source of resistance, two main genes are involved and in others only a single main gene. A probable explanation is that the highly resistant plants in Hajira may have differed genetically. The studies also reveal that the Hajira type of resistance to race 8, either in the seedling or adult stage, is indicative of resistance to the 12 races that occur in Canada and the United States.

SELFING STUDIES WITH PHYSIOLOGIC RACES OF WHEAT STEM RUST, PUCCINIA GRAMINIS VAR TRITICI

1954 ◽  
Vol 32 (4) ◽  
pp. 506-522 ◽  
Author(s):  
T. Johnson
Keyword(s):  
Stem Rust ◽  
Puccinia Graminis ◽  
Wheat Stem Rust ◽  
Recessive Character ◽  
Triticum Vulgare ◽  
Pathogenic Variation ◽  
Differential Hosts ◽  
Physiologic Races ◽  
Parent Race

Forty-two cultures of wheat stem rust (Puccinia graminis var. tritici Erikss. and Henn.), comprising 34 physiologic races, were subjected to selfing studies each of which involved the inoculation of barberry plants with the sporidia of a race, and the determination of the races in the uredial cultures derived from the aeciospores. In all of the cultures studied, the pathogenic properties expressed on the differential hosts appeared to be inherited according to the same principles. On the varieties Marquis and Kota (Triticum vulgare), pathogenicity of the races in the progeny tended to resemble that of the parent race. On Reliance (T. vulgare), avirulence was a dominant character, virulence a recessive one. On the durum wheats Arnautka, Mindum, and Spelmar, virulence was a dominant and avirulence a recessive character. On Einkorn (T. monococcum) and on Vernal (T. dicoccum), avirulence was dominant to virulence. In the progenies of some races, pathogenic variation occurred though it did not transgress the circumscribed limits of the parent race; the population therefore consisted chiefly of substrains (biotypes) of the same race.

Gene-for-gene relationships in the Avena: Puccinia graminis host–parasite system in Canada

1970 ◽  
Vol 48 (5) ◽  
pp. 969-975 ◽  
Author(s):  
J. W. Martens ◽  
R. I. H. McKenzie ◽  
G. J. Green
Keyword(s):  
North America ◽  
Resistance Genes ◽  
Stem Rust ◽  
Host Population ◽  
Puccinia Graminis ◽  
Physiologic Race ◽  
Host Genotype ◽  
Physiologic Races ◽  
Host Parasite ◽  
Gene For Gene

The results of 48 years of oat stem rust physiologic race surveys are interpreted in terms of the prevailing host genotype. Changes in the frequencies of genes that govern virulence in the pathogen can be explained only in part by changes in the resistance genes carried by the host population. Genes for virulence on newly released types of resistance have spread very quickly through the rust population, after initial 'breakdown' of the resistance. The most successful physiologic races carry genes for virulence in excess of those required for successful parasitism in North America. Many races carry genes for virulence on types of resistance that have never been used on this continent.

REPRODUCTIVE POTENTIALS OF RACES 15B AND 56 OF WHEAT STEM RUST

1967 ◽  
Vol 45 (7) ◽  
pp. 1077-1091 ◽  
Author(s):  
K. Katsuya ◽  
G. J. Green
Keyword(s):  
Incubation Period ◽  
Stem Rust ◽  
Selection Pressure ◽  
Field Conditions ◽  
Puccinia Graminis ◽  
Western Canada ◽  
Stages Of Development ◽  
Wheat Stem Rust ◽  
Wheat Varieties ◽  
Infection Density

Variations in the prevalence of races 56 and 15B-1 (Can.) of wheat stem rust (Puccinia graminis Pers. f. sp. tritici Erikss. and Henn.) have occurred that cannot be explained by changes in the wheat varieties grown in Western Canada. The reasons for the changes in prevalence were investigated by comparing in growth cabinets the reproductive potentials or aggressiveness of the two races and the factors that might influence them. When a mixture of urediospores of the two races was used to inoculate three susceptible varieties for successive uredial generations, race 56 predominated at 25 and 20 °C, and race 15B-1 (Can.) predominated at 15 °C. Experimentation showed that the urediospores of race 56 were more infective than those of 15B-1 (Can.) and that the incubation period of race 56 was shorter than that of race 15B-1 (Can.). Pustules of race 56 grew faster than those of race 15B-1 (Can.) during early stages of development but those of 15B-1 (Can.) ultimately became larger than those of race 56. Race 56 produced more urediospores per pustule than race 15B-1 (Can.) on the susceptible varieties Little Club, Red Bobs, and Marquis at 15 and 20 °C. Infection density markedly affected competitive abilities. Race 56 tended to predominate in light infections but race 15B-1 (Can.) tended to predominate in heavy infections. Pustule size decreased as infection density increased. The possible significance of these findings under field conditions is discussed. It seems likely that the rise of race 15B-1 (Can.) to predominance in 1950 resulted not only from the selection pressure of the widely grown varieties that were resistant to race 56 and susceptible to 15B-1 (Can.) but from the lower temperatures that prevailed and favored 15B-1 (Can.) over 56. The rise to predominance of race 56 from 1956 to 1961 may have resulted from the greater aggressiveness of that race under the moderate or warm conditions that prevailed.

THE EFFECT OF HIGH TEMPERATURE ON THE STEM RUST RESISTANCE OF WHEAT VARIETIES

1941 ◽  
Vol 19c (11) ◽  
pp. 438-445 ◽  
Author(s):  
T. Johnson ◽  
Margaret Newton
Keyword(s):  
High Temperature ◽  
Stem Rust ◽  
Rust Resistance ◽  
Stem Rust Resistance ◽  
Intermediate Temperature ◽  
Puccinia Graminis ◽  
Wheat Varieties ◽  
Different Temperatures ◽  
Physiologic Races ◽  
Moderately Resistant

Eighteen stem rust resistant wheat varieties were tested, in the greenhouse, for their reaction to three physiologic races of Puccinia graminis Tritici Erikss. and Henn. at three different temperatures: a constant low temperature of about 60° F., a constant high temperature of about 80° F., and an intermediate temperature which fluctuated daily from 50° to 55° F. at night to 70° to 85° F. at midday.At the low and at the intermediate temperature some of the varieties proved immune while others proved highly or moderately resistant. At the high temperature five varieties (Bokveld, Iumillo, Gaza, Red Egyptian, and N.A. 95 Egypt) were immune or highly resistant; six varieties (Marquillo × Waratah, Hope, Hochzucht, Minor, Bobin Gaza Robin, and Federation × Acme) were moderately resistant; and seven varieties (Kenya, Syria, McMurachy, Sweden, Rhodesian, Talberg, and Eureka) were moderately or completely susceptible.

Genes for stem rust resistance in Thatcher wheat

2009 ◽  
Vol 89 (6) ◽  
pp. 1003-1008
Author(s):  
D R Knott
Keyword(s):  
Triticum Aestivum ◽  
Common Wheat ◽  
Stem Rust ◽  
Rust Resistance ◽  
Triticum Aestivum L ◽  
Stem Rust Resistance ◽  
Puccinia Graminis ◽  
Genetic Studies ◽  
Number Of Genes ◽  
The Common

The common wheat (Triticum aestivum L.) cultivar Thatcher has resistance to many of the older races of stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & Henn.). Several genetic studies have shown that its resistance is complex in inheritance. To attempt to clarify the inheritance, 28 lines, each believed to carry a single resistance gene from Thatcher, were developed. The lines were tested with 13 races of stem rust. They fell into 13 types with resistance to from 1 to 11 races. Of the five genes previously identified in Thatcher, only two, Sr9g, and Sr12, were present in the lines. Four lines carried named genes, Sr6, Sr7a, Sr8a and S9d, which had not previously been detected in Thatcher. Thatcher is resistant to 8 of the 13 races. At least one line was resistant to each of the 13 races, including the five to which Thatcher is susceptible. Eleven of the 13 types of lines were resistant to race MCCD to which Thatcher is resistant. Seven of the types were resistant to race TMRT(15B-1) to which Thatcher is susceptible. Clearly, the inheritance of resistance in Thatcher is very complex and involves a considerable number of genes. It carries a surprising number of genes that appear to be hidden by the presence of suppressor genes or transposons.Key words: Common wheat, Triticum aestivum, Puccinia graminis, suppressors, tansposons

The genetic basis of isozyme variation in the wheat stem rust fungus (Puccinia graminis tritici)

1986 ◽  
Vol 28 (2) ◽  
pp. 171-175 ◽  
Author(s):  
J. J. Burdon ◽  
A. P. Roelfs ◽  
A. H. D. Brown
Keyword(s):  
Stem Rust ◽  
Genetic Basis ◽  
Rust Fungus ◽  
Puccinia Graminis ◽  
Isozyme Variation ◽  
Wheat Stem Rust ◽  
Single Linkage ◽  
Isozyme Loci ◽  
Sexual Cross ◽  
Physiologic Races

The pattern of inheritance of isozyme alleles was examined in the F2 progeny of a sexual cross between two different physiologic races of the wheat stem rust pathogen, Puccinia graminis Pers. f. sp. tritici Eriks. &Henn. Segregation occurred at five isozyme loci (Got, Lap, Nadhd, Pgi-2 and Pgm-1). In all of these, the observed number of F2 progeny of each of the three possible isozyme phenotypes did not differ significantly from a simple 1:2:1 ratio. Joint dihybrid segregation indicated that three of the loci formed a single linkage group: Lap–Nadhd–Pgi-2.Key words: linkage, segregation.

Histological studies on host-cell necrosis conditioned by the Sr6 gene for resistance in wheat to stem rust

1977 ◽  
Vol 55 (11) ◽  
pp. 1445-1452 ◽  
Author(s):  
D. J. Samborski ◽  
W. K. Kim ◽  
R. Rohringer ◽  
N. K. Howes ◽  
R. J. Baker
Keyword(s):  
Triticum Aestivum ◽  
Stem Rust ◽  
Fungal Growth ◽  
Triticum Aestivum L ◽  
Host Cells ◽  
Puccinia Graminis ◽  
Near Isogenic Lines ◽  
Cell Necrosis ◽  
Calcofluor White ◽  
Histological Studies

Seedlings of resistant (Sr6) and susceptible (sr6) near-isogenic lines of wheat (Triticum aestivum L.) were inoculated with a race of stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & E. Henn.) that was avirulent on the line with Sr6 and they were kept at 19, 25, 26, and 27 °C. Fluorescence microscopy was used to detect autofluorescing necrotic host cells and rust colonies after these were stained with a fiuorochrome (Calcofluor White M2R New).In leaves containing the Sr6 gene, a smaller percentage of colonies grown at 25 °C had necrotic cells associated with them than those that were grown at 19 °C. The incidence of colony-associated necrosis in these leaves could be further reduced by increasing the temperature to 26 °C and 27 °C. Similarly, the number of necrotic host cells per colony decreased with an increase in temperature. Colonies in genotypically resistant leaves were usually smaller than those in genotypically susceptible leaves, but the differences in colony sizes between these two lines decreased at the higher temperatures.When infected plants containing the Sr6 gene were kept for varying times at 25 °C and then were transferred to 19 °C, there was significantly less fungal growth and more necrosis than in plants kept continuously at 25 °C. This necrosis occurred largely in those cells that were invaded after the transfer to 19 °C, when the Sr6 gene was activated.

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