ENVIRONMENTAL REACTION OF PHYSIOLOGIC RACES OF PUCCINIA TRITICINA AND THEIR DISTRIBUTION IN CANADA

1941 ◽  
Vol 19c (4) ◽  
pp. 121-133 ◽  
Author(s):  
Margaret Newton ◽  
T. Johnson

Studies were made of the effect of temperature and light on the reactions to leaf rust (Puccinia triticina Erikss.) of the differential varieties of wheat used for the identification of physiologic races of this rust. With a large number of races both temperature and light were found to exercise a marked influence. The reactions of all varieties were not, however, influenced in the same direction. With lower temperature, Malakof and Democrat became increasingly susceptible, while Carina, Brevit, and Hussar became increasingly resistant. Webster and Mediterranean did not react consistently in either direction, and Loros was but little influenced by temperature. All of the differential varieties showed a more or less marked tendency to become increasingly resistant under conditions of short day length and weak light. In general, more pronounced changes in reaction were produced by variation of temperature than of light.Surveys for the distribution of physiologic races of leaf rust in Canada were conducted annually since 1931 with the exception of the years 1932 and 1935. Forty-nine races were identified. Most of the prevailing physiologic races were found to be widely distributed throughout the country. Evidence was, however, secured that certain races were largely confined to certain areas. Races 1, 58, 76, and 81 were common for several years in Eastern Canada but were not encountered in the Prairie Provinces until 1940 when one collection of each of the three first-mentioned was made in that area. Races 11 and 53 were largely limited to British Columbia and the adjacent province of Alberta. Races of wheat leaf rust have undergone no marked change in respect to identity or relative prevalence in the last few years in Canada.

1949 ◽  
Vol 27c (5) ◽  
pp. 191-202 ◽  
Author(s):  
A. M. Brown ◽  
T. Johnson

In experiments designed to clarify the causes of the pathogenic changes that have recently been encountered in leaf rust of wheat, two factors were given consideration, (1) the possibility that nuclear exchanges might occur between the mycelia of different races in the uredial stage, and (2) the possible role of Thalictrum species in originating new rust strains. Infection studies with mixtures of races 9 and 15 and mixtures of races 5 and 9 did not produce any evidence that these races could interchange nuclei and thus initiate new pathogenic strains of leaf rust.In greenhouse infection tests with native Thalictrum spp., aecia were produced on T. dasycarpum, pycnia only on T. dioicum and T. polygamum, while no infection of T. venulosum took place. In similar tests with the introduced species T. glaucum and T. dipterocarpum, abundant production of aecia occurred on both species. In out-of-doors inoculation tests with T. dasycarpum and T. venulosum, no infection of these two species took place, whereas, under the same conditions, heavy aecial production occurred on the introduced species T. glaucum.Selfing studies in which Thalictrum glaucum was infected with known physiologic races have indicated that some races of leaf rust are homozygous, and others heterozygous for pathogenic characters. A culture of race 5 appeared to be homozygous, whereas a culture of race 3 was heterozygous, giving rise to races 3, 15, 32, 68, and three undescribed races. A culture of race 76 was heterozygous for both pathogenicity and urediospore color. Aeciospores of this race produced uredia of two different shades of yellow in addition to uredia of normal color. Aeciospores derived from teliospores collected in the field also gave rise to uredial strains of yellow spore color. Most of the yellow rust strains were decidedly low in pathogenic vigor.


1943 ◽  
Vol 21c (1) ◽  
pp. 10-17 ◽  
Author(s):  
Margaret Newton ◽  
T. Johnson

Nine wheat varieties were studied in two stages of growth, the seedling stage and the heading stage, for their reaction to a number of physiologic races of leaf rust of wheat, Puccinia triticina Erikss. Several varieties susceptible to certain physiologic races in the seedling stage were found to acquire, as they grew to maturity, a resistance to these races. In the adult plant, the resistance was greatest in the uppermost leaves but diminished progressively on lower leaves. The varieties tested fell into three groups on the basis of their rust reaction. (1) Renown and Regent, which developed adult plant resistance to all of the 19 races to which they were tested. In these two varieties, and possibly in other derivatives of H-44 and Hope, adult plant resistance to physiologic races of leaf rust may be a generalized phenomenon comparable to the resistance such varieties show towards stem rust. (2) Thatcher, Apex, Marquis, Reward, and Kenya R.L. 1373, which showed adult plant resistance only to certain physiologic races, a condition not hitherto encountered in other cereal rusts. (3) McMurachy and Warden × Hybrid, each of which reacted somewhat similarly in the seedling and heading stages, the former being susceptible and the latter resistant in both stages.


2011 ◽  
Vol 42 (No. 4) ◽  
pp. 126-131 ◽  
Author(s):  
A. Hanzalová ◽  
P. Bartoš

In 2001–2004 virulence of the wheat leaf rust population in the Czech Republic was studied on Thatcher near-isogenic lines with Lr1, Lr2a, Lr2b, Lr2c, Lr3a, Lr9, Lr10, Lr11, Lr15, Lr17, Lr19, Lr21, Lr23, Lr24, Lr26 and Lr28. Samples of leaf rust (180 in total) were obtained from different parts of the Czech Republic. Resistance genes Lr9 and Lr19 were effective to all tested isolates like in the previous years. Unlike the previous years virulence on Lr24 and Lr28 was observed. Relatively effective were also Lr1, Lr2a, Lr24, Lr28 and Lr2b. Other Lr genes were defeated by the majority of the tested samples. Our results transformed to the numbers of physiologic races indicate that race 61SaBa prevailed like in the previous years, followed by races 61, 2, 12SaBa, 2SaBa, 14, 77SaBa, 12, 57, 6, 53, 53SaBa, 77, and 14SaBa. Twenty-one winter wheat cultivars registered in 2001–2004 were tested with 8 leaf rust isolates. Out of them 15 showed resistance at least to one rust isolate. High resistance recorded in field trials for cvs Batis and Ilias, which were susceptible to all tested rust isolates at the seedling stage, demonstrates the importance of field (partial) resistance.  


2020 ◽  
Vol 0 (0) ◽  
pp. 0-0
Author(s):  
Walid El-Orabey ◽  
Dalia Shaheen ◽  
Ola Mabrouk ◽  
Ahmed Elkot ◽  
Samar Esmail

2012 ◽  
Vol 1 (1) ◽  
pp. 73-80 ◽  
Author(s):  
Nour E. K. Soliman ◽  
Ashraf M. M. Abdelbacki ◽  
Mohammad A.A. Najeeb ◽  
Reda I. Omara

Knowledge of the geographical distribution for physiologic races of Puccinia triticina and identification of leaf rust resistance genes (Lr ,s) in the recent Egyptian wheat cultivars are essential for maximizing resistance in future-bred cultivars. The  aim   of   this   study   was   to   know   the   status  of resistance in Egyptian wheat cultivars against wheat leaf rust and the most frequent race distributed. Infected samples were collected from five Governorates, i.e.,  Dakahlia,  Kafr el-Sheikh,  Beheira,  Sharqia  and  Sohag comprised the wheat growing area in Egypt. These samples were isolated, purified and identified on the differential stes. Gene postulation was done using fifteen identified races on Egyptian wheat cultivars correlated with Lr genes. Thirty three races identified during three seasons 2009/2010, 2010/2011 and 2011/2012. The most frequent race was TK (10%) followed by race BB (7.58%), PK (6.55%), TT (4.82%), PT (3.79%) and MT (3.44%). Moreover, races; BB, TT and PT were present during three seasons while these races appeared in some Governorates and disappeared in other Governorates. On the other hand, the most frequently occurring gene in ten Egyptian wheat cultivars was Lr35 (70%), followed by Lr22 (60%), Lr27 (40%), Lr34 (30%), Lr19 (30%),Lr18 (10%),Lr36 (10%) and Lr46 (10%), eight out of sixteen Lr genes were not present in the tested cultivars. It is concluded that there was a good variation in Lr genes carried by wheat cultivars commercially grown in Egypt. Therefore, strategies for deploying resistance genes to prolong effective disease resistance are suggested to control wheat leaf rust disease.


1942 ◽  
Vol 20c (2) ◽  
pp. 108-115 ◽  
Author(s):  
Yun-Chang Wang

About 160 Chinese spring wheats and a number of Chinese winter wheats were tested in the seedling stage in the greenhouse to determine their reaction to eight physiologic races of stem rust (Puccinia graminis Tritici) and to four physiologic races of leaf rust (Puccinia triticina). The spring wheats were also subjected, in the field, to epidemics of stem rust and leaf rust in which a large number of physiologic races of each rust were employed. The wheats were classified as one or another of the following species: Triticum vulgare, T. compactum, T. durum, and T. turgidum.By means of these tests, it has been demonstrated that the Chinese wheats are rather highly susceptible to the physiologic races of stem rust prevalent in North America. Many of the wheats showed, however, considerable resistance to leaf rust in both the greenhouse and the field tests. Varieties resistant to leaf rust were present in all of the four above-mentioned species.Seventy-five lines of Canadian spring wheat derived from a cross between Renown Selection, which is resistant to stem rust and moderately resistant to leaf rust, and Garnet, which in North America is resistant to stripe rust (Puccinia glumarum), were tested in the seedling stage in the greenhouse for their reaction to stripe rust. Two physiologic races (race 6 and race 13) were used in these tests. The same lines were subjected to rust epidemics in the field to determine their resistance to stem rust and leaf rust. Several of these lines were found to possess resistance to all three rusts. These lines may prove valuable breeding material in case it is desired to develop by breeding methods Chinese varieties resistant to all three of these rusts.


Author(s):  
G. V. Volkova ◽  
O. A. Kudinova ◽  
O. F. Vaganova

Currently, more than 70 wheat rust resistance genes are known, but few of them are effective. The purpose of this work is to screen lines of Lr gene carriers for resistance to leaf rust under conditions of the North Caucasus region. Investigations were carried out in 2016-2018 at the infectious site of VNIIBZR. Research material was 49 near isogenic lines of winter wheat cultivar Thatcher. Infectious material was the combined populations of P. triticina, obtained as a result of route surveys of industrial and breeding crops of winter wheat in the areas of the Krasnodar, Stavropol Territories and the Rostov Region, conducted in 2016-2018. According to the assessment, the genes are ranked as follows: - highly efficient genes (plants with no signs of damage): Lr9, Lr42, Lr43 + 24 and Lr50; effective (1R-5R) Lr genes: 19, 24, 29, 36, 37, 38, 45, 47; moderately effective (10MR-20MR) Lr genes: 17, 18, 21, 22a, 28, 32, 41, 52. The remaining Lr-lines were susceptible to P. triticina (25 MR - 90S) to varying degrees. Highly efficient and effective genes Lr9, Lr19, Lr24, Lr29, Lr38, Lr42, Lr43 + 24, Lr47 and Lr50 showed resistance in the seedling phase and can be recommended for inclusion in breeding programs to protect wheat from leaf rust in different phases of plant ontogenesis in the North Caucasus region.


2016 ◽  
Vol 106 (4) ◽  
pp. 380-385 ◽  
Author(s):  
J. A. Kolmer ◽  
M. A. Acevedo

Collections of Puccinia triticina, the wheat leaf rust fungus, were obtained from tetraploid and hexaploid wheat in the central highlands of Ethiopia, and a smaller number from Kenya, from 2011 to 2013, in order to determine the genetic diversity of this wheat pathogen in a center of host diversity. Single-uredinial isolates were derived and tested for virulence phenotype to 20 lines of Thatcher wheat that differ for single leaf rust resistance genes and for molecular genotypes with 10 simple sequence repeat (SSR) primers. Nine virulence phenotypes were described among the 193 isolates tested for virulence. Phenotype BBBQJ, found only in Ethiopia, was predominantly collected from tetraploid wheat. Phenotype EEEEE, also found only in Ethiopia, was exclusively collected from tetraploid wheat and was avirulent to the susceptible hexaploid wheat ‘Thatcher’. Phenotypes MBDSS and MCDSS, found in both Ethiopia and Kenya, were predominantly collected from common wheat. Phenotypes CCMSS, CCPSS, and CBMSS were found in Ethiopia from common wheat at low frequency. Phenotypes TCBSS and TCBSQ were found on durum wheat and common wheat in Kenya. Four groups of distinct SSR genotypes were described among the 48 isolates genotyped. Isolates with phenotypes BBBQJ and EEEEE were in two distinct SSR groups, and isolates with phenotypes MBDSS and MCDSS were in a third group. Isolates with CCMSS, CCPSS, CBMSS, TCBSS, and TCBSQ phenotypes were in a fourth SSR genotype group. The diverse host environment of Ethiopia has selected and maintained a genetically divergent population of P. triticina.


Plant Disease ◽  
2015 ◽  
Vol 99 (9) ◽  
pp. 1261-1267 ◽  
Author(s):  
J. A. Kolmer ◽  
M. E. Hughes

Collections of Puccinia triticina were obtained from rust-infected leaves provided by cooperators throughout the United States and from wheat fields and breeding plots by USDA-ARS personnel and cooperators in the Great Plains, Ohio River Valley, and southeastern states in order to determine the virulence of the wheat leaf rust population in 2013. Single uredinial isolates (490 total) were derived from the collections and tested for virulence phenotype on 20 lines of Thatcher wheat that are near-isogenic for leaf rust resistance genes. In 2013, 79 virulence phenotypes were described in the United States. Virulence phenotypes MBTNB, TNBGJ, and MCTNB were the three most common phenotypes. Phenotypes MBTNB and MCTNB are both virulent to Lr11, and MCTNB is virulent to Lr26. MBTNB and MCTNB were most common in the soft red winter wheat region of the southeastern states and Ohio Valley. Phenotype TNBGJ is virulent to Lr39/41 and was widely distributed throughout the hard red winter wheat region of the Great Plains. Isolates with virulence to Lr11, Lr18, and Lr26 were common in the southeastern states and Ohio Valley region. Isolates with virulence to Lr21, Lr24, and Lr39/41 were frequent in the hard red wheat region of the southern and northern Great Plains.


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