ANTIBIOTIC P-9 IN THE CONTROL OF CEREAL RUSTS

1961 ◽  
Vol 39 (7) ◽  
pp. 1725-1732 ◽  
Author(s):  
W. A. F. Hagborg ◽  
W. S. Chelack ◽  
J. F. T. Spencer

Recurrent outbreaks of stem rust, Puccinia graminis Pers. f. sp. tritici Erikss. & Henn., following the widespread use of previously rust-resistant wheat varieties have emphasized the need of alternative means of rust control. A new antibiotic, P-9, available as yet only in impure form, has several properties that suggest its potential usefulness in the control of cereal rusts. It has systemic and eradicative action, is non-phytotoxic to the host crop at concentrations of a higher order than required for the control of cereal rusts, is probably non-zootoxic, and is highly water-soluble.In greenhouse tests P-9 arrested infection completely in leaf rust, P. recondita Rob. ex Desm., and in stem rust and it was apparently translocated more readily distally than proximally. In field plot tests in 1959 and 1960 it reduced rust infection and increased yield substantially.

1971 ◽  
Vol 51 (6) ◽  
pp. 457-461 ◽  
Author(s):  
R. J. BAKER

The two approaches used to assess the effects of infection with stem rust (Puccinia graminis Pers. f. sp. tritici) and leaf rust (Puccinia recondita Rob. ex. Desm.) on the estimation of genotype-environment interaction for yield in wheat, Triticum aestivum L. em Thell., showed that rust infection is an important consideration. The results suggest that much of the genotype-environment interaction in quantitative traits may be due to rather simply inherited traits.


2011 ◽  
Vol 59 (3) ◽  
pp. 241-248 ◽  
Author(s):  
G. Vida ◽  
M. Cséplő ◽  
G. Gulyás ◽  
I. Karsai ◽  
T. Kiss ◽  
...  

Among the factors which determine yield reliability an important role is played by disease resistance. One of the breeding aims in the Martonvásár institute is to develop wheat varieties with resistance to major diseases. The winter wheat varieties bred in Martonvásár are examined in artificially inoculated nurseries and greenhouses for resistance to economically important pathogens. The effectiveness of designated genes for resistance to powdery mildew and leaf rust has been monitored over a period of several decades. None of the designated major resistance genes examined in greenhouse tests is able to provide complete resistance to powdery mildew; however, a number of leaf rust resistance genes provide full protection against pathogen attack (Lr9, Lr19, Lr24, Lr25, Lr28 and Lr35). In the course of marker-assisted selection, efficient resistance genes (Lr9, Lr24, Lr25 and Lr29) have been incorporated into Martonvásár wheat varieties. The presence of Lr1, Lr10, Lr26, Lr34 and Lr37 in the Martonvásár gene pool was identified using molecular markers. New sources carrying alien genetic material have been tested for powdery mildew and leaf rust resistance. Valuable Fusarium head blight resistance sources have been identified in populations of old Hungarian wheat varieties. Species causing leaf spots (Pyrenophora tritici-repentis, Septoria tritici and Stagonospora nodorum) have gradually become more frequent over the last two decades. Tests on the resistance of the host plant were begun in Martonvásár four years ago and regular greenhouse tests on seedlings have also been initiated.


1976 ◽  
Vol 54 (19) ◽  
pp. 2204-2214 ◽  
Author(s):  
Mishael Oichoe Osoro ◽  
G. J. Green

Experiments were designed to show whether or not virulence genes reduce fitness and bring about stabilizing selection. The competitive abilities of seven related races of Puccinia graminis f. sp. tritici were studied on seedlings of three to five susceptible wheat varieties by growing mixtures of the races in greenhouses, growth cabinets, and field plots. In experiments in which simple races with few virulence genes were mixed with complex races with one, two, or three extra virulence genes, the complex races predominated after 4 to 10 generations in five of the six mixtures, and the simple race predominated in one mixture. A complex race predominated over simple races in the field experiment. It was concluded that virulence genes did not impair the fitness of the wheat stem rust races studied.In one race mixture studied in growth cabinets the complex race predominated at 25 °C, and the simple race, at 15 °C. Temperature did not differentially influence the competitive abilities of the races in three other mixtures.Incubation periods for all races were shorter at higher temperatures, but races C18(15B-1L) and C33(15B-1L) developed faster than races C9(15B-1L), C37(15), C38(15B-1L), C42(15), and C49(15) at all temperatures. In addition, races C18(15B-1L) and C33(15B-1L) produced more urediospores per pustule than races C9(15B-1L), C37(15), and C49(15). The differences in incubation period and spore production are considered to be the most important factors studied and they could cause the differences in aggressiveness of the seven races.


1960 ◽  
Vol 38 (1) ◽  
pp. 1-7 ◽  
Author(s):  
D. J. Samborski ◽  
Clayton Person ◽  
F. R. Forsyth

The effect of maleic hydrazide on leaf rust and stem rust of wheat was investigated, using intact plants supplied with maleic hydrazide through the roots, detached leaves floated on solutions of maleic hydrazide, and spores germinated on maleic hydrazide solutions in agar. In each case the growth of leaf rust was inhibited at concentrations of maleic hydrazide which had no effect on the growth of stem rust. Some resistant wheat varieties became susceptible to rust after treatments with levels of maleic hydrazide which were not inhibitory to rust development. In some experiments, leaf rust races reacted differentially to maleic hydrazide. Both nutritional and inhibitory factors could be involved in resistance and host–pathogen specificity.


1966 ◽  
Vol 46 (5) ◽  
pp. 537-543
Author(s):  
W. A. F. Hagborg

Dried crude filtrate (DCF) from Streptomyces sp., containing antibiotic P-9, was compared in 1962 with a mixture of nickel chloride and zineb and in 1964 with symmetrical dichlorotetrafluoroacetone (DCTFA) for the control of cereal rusts on Marquis wheat. Seven applications of DCF gave significantly better control of stem rust on the sheaths than six applications of nickel–zineb. The control of stem rust on the necks and of leaf rust was equally good for both materials. Rust control by either material resulted in a substantial improvement of yield and grade. When 280 kg/ha of DCF, a quantity equal to that used successfully in three applications over a period of 4 weeks, was applied in a single application, less control was obtained and some phytotoxic necrosis occurred. The phototoxicity may have been due to an extraneous substance in the DCF, and might not be a limiting factor with purified or partially purified preparations.Under the conditions of the experiment in 1964, DCTFA was not as effective as DCF in rust control.


1937 ◽  
Vol 15c (9) ◽  
pp. 425-432 ◽  
Author(s):  
Thorvaldur Johnson ◽  
Margaret Newton

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.


1977 ◽  
Vol 28 (1) ◽  
pp. 37 ◽  
Author(s):  
RA McIntosh ◽  
PL Dyck ◽  
GJ Green

The wheat cultivars Agent and Agatha each possess closely linked genes for resistance to Puccinia graminis tritici and P. recondita derived from Agropyron elongatum. The genes in Agent, located in chromosome 3D, were designated Sr24 and Lr24. The gene in Agatha for resistance to P. graminis tritici was designated Sr25 and is linked with Lr19 in chromosome 7D. Both Agent and Agatha possess additional genes for resistance to certain cultures of P. graminis tritici. Sr24 is considered a valuable source of resistance for wheat-breeding purposes, but Sr25 conferred an inadequate level of resistance to adult plants. A translocation from an A. elongatum chromosome to wheat chromosome 6A, present in Australian cultivars Eagle, Kite and Jabiru, carries a third gene, Sr26, for stem rust resistance.


1967 ◽  
Vol 45 (7) ◽  
pp. 1077-1091 ◽  
Author(s):  
K. Katsuya ◽  
G. J. Green

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.


1941 ◽  
Vol 19c (11) ◽  
pp. 438-445 ◽  
Author(s):  
T. Johnson ◽  
Margaret Newton

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.


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