scholarly journals The Nature of Cold-induced Dormancy in Urediospores of Puccinia graminis tritici

1971 ◽  
Vol 47 (2) ◽  
pp. 289-295 ◽  
Author(s):  
Ramesh Maheshwari ◽  
Alfred S. Sussman
Keyword(s):  
Puccinia Graminis ◽  
Puccinia Graminis Tritici

Epidemiology of Puccinia graminis f.sp. tritici-Ug99 in the Rift Valley “Flyway” from Uganda-Kenya to Yemen

2012 ◽  
Vol 13 (1) ◽  
pp. 31 ◽  
Author(s):  
Subrahmaniam Nagarajan ◽  
Hans J. Kogel ◽  
Jan C. Zadoks
Keyword(s):  
Rift Valley ◽  
Puccinia Graminis ◽  
Puccinia Graminis Tritici ◽  
Wheat Cultivation

Dispersal of a new virulence of Puccinia graminis tritici (Pgt)-Ug99 from Uganda-Kenya to Yemen, over >1000 km, happened in four years. Geo-agro-ecology of wheat cultivation and the epidemiology of Pgt indicate that the Rift Valley is a natural conduit “flyway.” The widely prevalent “green bridges” favor survival and spread of Pgt. This part of the Rift Valley is one single epidemiological zone, and the annual Pgt build-up is from the endogenous inoculum. Accepted for publication 18 October 2012. Published 14 November 2012.

scholarly journals A Third Factor for Resistance to Puccinia graminis Tritici

Nature ◽  
1945 ◽  
Vol 155 (3929) ◽  
pp. 205-205
Author(s):  
I. A. WATSON ◽  
W. L. WATERHOUSE
Keyword(s):  
Puccinia Graminis ◽  
Puccinia Graminis Tritici

STUDIES ON THE NATURE OF RUST RESISTANCE IN WHEAT: VI. EFFECT OF HYDROGEN ION CONCENTRATION, PHENOLIC COMPOUNDS, AND HOST EXTRACTS ON THE GERMINATION OF UREDINIOSPORES OF PUCCINIA GRAMINIS TRITICI, FORM 21

1934 ◽  
Vol 11 (6) ◽  
pp. 667-686 ◽  
Author(s):  
J. Ansel Anderson
Keyword(s):  
Phenolic Compounds ◽  
Rust Resistance ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Puccinia Graminis ◽  
Inhibitory Effects ◽  
Hydrogen Ion Concentration ◽  
Puccinia Graminis Tritici ◽  
The Press ◽  
Germ Tubes

Urediniospores of Puccinia graminis tritici, form 21, were sown on buffer solutions covering the range from pH 3 to pH 8. Maximum germination was obtained between pH 5.8 and 6.5, with indications that if the point of maximum germination could be determined with precision it would be found to lie in the neighborhood of pH 6.2.The effect of buffered and unbuffered solutions of pure phenolic compounds on the germination of urediniospores was studied. Greater inhibition was obtained with unbuffered solutions owing to the additional effect of hydrogen ion concentration. In buffered solutions, at pH 6.0, germination was prevented by 45 p.p.m. of hydroquinone, 125 of o-cresol, 180 of anisic acid, 250 of benzoic acid, 340 of catechol, 400 of guaiacol and 600 of phenol. A number of other compounds were also studied. The inhibitory effects of compounds, of which the bactericidal effects are known, are fairly closely related to their bactericidal efficiency.Investigations were made of the inhibitory effects on spore germination and the growth of germ tubes, of aqueous dilutions of 15, 10, 5 and 2.5% of the press-juice of Vernal, Khapli, Marquis and Little Club wheats. Statistical treatment of the data accumulated in ten series of determinations, in which a total of 160,000 spores was counted, showed that significant differences occurred between varieties and that variations in the total solid content and hydrogen ion concentration of the press-juice had no consistent effect upon the results. Although the results were not entirely clear-cut, it is concluded that the varieties fall in the following order with respect to increasing inhibitory effect of their extracts: Vernal, Marquis, Khapli and Little Club. Since Vernal and Khapli are resistant to form 21 whereas Marquis and Little Club are susceptible, the results fail to show any relationship between the effects of host extracts on the germination of urediniospores, or on the growth of germ tubes, and the rust resistance of the variety.

THE EFFECTS OF GENOTYPE AND TEMPERATURE ON THE RESISTANCE TO PUCCINIA GRAMINIS TRITICI CONTROLLED BY THE GENE Sr6 IN TRITICUM AESTIVUM

1981 ◽  
Vol 23 (2) ◽  
pp. 183-190 ◽  
Author(s):  
D. R. Knott
Keyword(s):  
Triticum Aestivum ◽  
Genetic Background ◽  
Triticum Aestivum L ◽  
Complex Interaction ◽  
Puccinia Graminis ◽  
Susceptible Parent ◽  
Puccinia Graminis Tritici ◽  
Modifier Locus ◽  
Maximum Resistance ◽  
Growth Chambers

A line of wheat (Triticum aestivum L.). Kenya 58/10* Marquis (K58Mq10), homozygous for gene Sr6 for resistance to stem rust (Puccinia graminis tritici Eriks. and Henn.), was crossed with four rust susceptible cultivars or lines. The F1 seedlings were tested with rust races 56 and 15B-1, twice under greenhouse conditions and three times in growth chambers, and F2 seedlings were tested twice in the greenhouse. In conditions that resulted in maximum resistance, Sr6 was dominant with both race 56 and race 15B-1 in two crosses, dominant with race 56 and recessive with race 15B-1 in one cross, and recessive with both races in the fourth cross. Thus, the dominance of Sr6 depended on the susceptible parent with which K58Mq10 had been crossed. The data indicated that the dominance of Sr6 was not controlled either by a single independent modifier locus or by the general genetic background of the susceptible parents. Although the possibility of a linked modifier has not been eliminated, it appears that the results may be due to the effects of different alleles for susceptibility at the Sr6 locus. The degree of resistance conditioned by Sr6 is determined by a complex interaction between genotype and environment.

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