scholarly journals Pyramiding winter wheat resistance genes (Pm21 + Pm34) of powdery mildew of cereals and grasses (Blumeria graminis f. sp. tritici)

2017 ◽  
Keyword(s):  
Powdery Mildew ◽  
Winter Wheat ◽  
Resistance Genes ◽  
Blumeria Graminis

scholarly journals Evaluation of resistance to powdery mildew and identification of resistance genes in wheat cultivars

2020 ◽  
Author(s):  
Xian Xin Wu ◽  
Yue Gao ◽  
Qiang Bian ◽  
Qian Sun ◽  
Xin Yu Ni ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Large Scale ◽  
Durable Resistance ◽  
Cost Effective ◽  
Blumeria Graminis ◽  
Wheat Cultivars ◽  
Seedling Resistance ◽  
Initial Inoculum ◽  
Wheat Powdery Mildew

Abstract Background: Wheat powdery mildew, caused by the biotrophic fungus Blumeria graminis f. sp. tritici ( Bgt ), is a serious disease of wheat worldwide that can cause significant yield losses. Growing resistant cultivars is the most cost-effective and eco-soundly strategy to manage the disease. Therefore, a high breeding priority is to identify genes that can be readily used either singly or in combination for effective resistance to powdery mildew and alos in combination with genes for resistance to other diseases. Yunnan Province, with complex and diverse ecological environments and climates, is one of the main wheat growing regions in China. This region provides initial inoculum for starting epidemics of wheat powdery mildew in the region and other regions and thus, plays a key role in the regional and large-scale epidemics of the disease throughout China. The objectives of this study were to evaluate seedling resistance of 69 main wheat cultivars to powdery mildew and to determine the presence of resistance genes Pm3 , Pm8 , Pm13 , Pm16 , and Pm21 in these cultivars using gene specific DNA markers. Results: Evaluation of 69 wheat cultivars with six Bgt isolates showed that only four cultivars were resistant to all tested isolates, indicating that the overall level of powdery mildew resistance of Yunnan wheat cultivars is inadequate. The molecular marker results showed that 27 cultivars likely have at least one of these genes. Six cultivars were found likely to have Pm3 , 18 likely to have Pm8 , 5 likely to have Pm16 , and 3 likely to have Pm21 . No cultivar was found to carry Pm13 . Conclusion: The information on the presence of the Pm resistance genes in Yunnan wheat cultivars can be used in future wheat disease breeding programs. In particular, cultivars carrying Pm21 , which is effective against all Bgt races in China, should be pyramided with other effective genes to developing new cultivars with durable resistance to powdery mildew. Keywords: Blumeria graminis f. sp. tritici , Pm gene, molecular markers, wheat

scholarly journals Appearance of Powdery Mildew of Wheat Caused by Blumeria graminis f. sp. tritici on Pm17-Bearing Cultivars in North Carolina

Plant Disease ◽  
2009 ◽  
Vol 93 (11) ◽  
pp. 1219-1219 ◽  
Author(s):  
C. Cowger ◽  
R. Parks ◽  
D. Marshall
Keyword(s):  
United States ◽  
North Carolina ◽  
South Carolina ◽  
Powdery Mildew ◽  
Winter Wheat ◽  
Triticum Aestivum L ◽  
Blumeria Graminis ◽  
Low Frequencies ◽  
Multiple Strains ◽  
Red Winter Wheat

Pm17 is a gene for resistance to powdery mildew caused by Blumeria graminis (DC.) E.O. Speer f. sp. tritici. The gene was first confirmed in the wheat-rye translocation cultivar Amigo (1). In Amigo, the translocation is T1AL-1RS and the 1RS arm has the gene Pm17. In the mid-Atlantic United States, at least two widely deployed soft red winter wheat (Triticum aestivum L.) cultivars, McCormick (2) and Tribute (3), possess Pm17 inherited from Amigo. Before 2009, low frequencies of mostly intermediate virulence to Pm17 were detected among isolates from research plots of highly susceptible cultivars (4), but Pm17-bearing cultivars remained immune to mildew in the field. In April 2009, moderately severe powdery mildew was observed for the first time throughout plots of McCormick, Tribute, and other cultivars in both Kinston and Raleigh, NC. At Kinston, Pm17 virulence was observed at two research sites, separated by approximately 10 km, throughout plots of Amigo, McCormick, Tribute, and the hard red winter wheat cultivar TAM 303, which also contains Pm17. In the same month, virulence to Pm17 was observed in Raleigh throughout rows and plots of Amigo and TAM 303. In Kinston and Raleigh, ratings of powdery mildew severity on the Pm17-containing cultivars were 4 or 5 on a scale of 0 to 9, with 0 being the absence of mildew pustules and 9 the most severe mildew infection. Mildew was observed on leaves of all ages. Mildewed leaves were collected from field plots of all four Pm17-bearing cultivars, and an assay to confirm Pm17 virulence was conducted in the laboratory. Mixed-isolate cultures were derived from the leaves and a detached-leaf assay was performed using Amigo, which is the standard Pm17 differential (4). All tested cultures were fully to moderately virulent on Pm17 and all were fully virulent on the susceptible control Chancellor. In the field, chasmothecia (sexual fruiting bodies) were observed on Pm17-bearing cultivars. Together with the quantitatively varying Pm17 virulence detected in the laboratory assay, this suggests that multiple strains of Pm17-virulent B. graminis f. sp. tritici may be present in the field, although that has not yet been demonstrated. Pm17 has protected wheat from powdery mildew over a substantial area in the mid-Atlantic United States. The loss of Pm17 is the most important virulence shift in the U.S. wheat powdery mildew population since Pm4a became ineffective around 2002. Isolates virulent to Pm17 can be expected to appear and multiply in wheat-producing states of the mid-Atlantic United States, including Delaware, Maryland, Virginia, North Carolina, South Carolina, and Georgia. Thus, the urgency of developing and releasing wheat cultivars with other sources of effective mildew resistance is heightened. References: (1) B. Friebe et al. Euphytica 91:59, 1996. (2) C. A. Griffey et al. Crop Sci. 45:416, 2005. (3) C. A. Griffey et al. Crop Sci. 45:419, 2005. (4) R. Parks et al. Plant Dis. 92:1074, 2008.

scholarly journals Deriving isolates of powdery mildew (Blumeria graminis DC. f.sp. avenae Em. Marchal.) in common oat (Avena sativa L.) and using them to identify selected resistance genes

2012 ◽  
Vol 65 (2) ◽  
pp. 155-160 ◽  
Author(s):  
Sylwia Okoń ◽  
Krzysztof Kowalczyk
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Avena Sativa ◽  
Blumeria Graminis ◽  
Matching Model ◽  
F2 Population ◽  
Host Pathogen ◽  
Dominant Genes

Powdery mildew in common oat is caused by <i>Blumeria graminis</i> DC. f.sp. <i>avenae</i> Em. Marchal. Host-pathogen tests are commonly used to identify and locate resistance genes to powdery mildew in cereals. The aim of the study was to determine the virulence of powdery mildew isolates obtained from powdery mildew populations harvested in Poland and to identify OMR1, OMR2 and OMR3 resistance genes to powdery mildew in F<sub>2</sub> populations of inter-cultivar hybrids of common oat: Bruno × Fuchs, Jumbo × Fuchs and Mostyn × Fuchs. On the basis of the analysis conducted, isolates enabling division of the studied populations into groups of resistant and susceptible plants were selected. M10 and M14 isolates were chosen for the population which was obtained from crossbreeding of ‘Bruno’ with ‘Fuchs’; these isolates demonstrated avirulence to Bruno cultivar containing OMR1 gene. In order to divide population obtained from crossbreeding of ‘Jumbo’ with ‘Fuchs’, M13 and M16 isolates were chosen; they demonstrated avirulence to the cultivar Jumbo containing the OMR2 gene. On the basis of the tests conducted, it was impossible to select isolates characterised by avirulence to the OMR3 gene. In the F2 population of Bruno × Fuchs and Jumbo × Fuchs hybrids, a division was made into resistant and susceptible plants. The obtained results were verified by the <sup>2</sup> test; the proportion in the dispersion matching model was found to be 3 resistant plants: 1 sensitive plant both in the Bruno × Fuchs and Jumbo × Fuchs populations. Such dispersion indicated that the resistance to powdery mildew in the studied cultivars Bruno and Jumbo was conditioned by single dominant genes.

scholarly journals Virulence of Blumeria graminis f. sp. tritici on Winter Wheat in the Eastern United States

Plant Disease ◽  
1998 ◽  
Vol 82 (1) ◽  
pp. 64-68 ◽  
Author(s):  
A. S. Niewoehner ◽  
S. Leath
Keyword(s):  
United States ◽  
Winter Wheat ◽  
Resistance Genes ◽  
Virulence Genes ◽  
Southeastern United States ◽  
Blumeria Graminis ◽  
Eastern United States ◽  
Single Spore ◽  
Differential Host ◽  
Wheat Leaves

Samples of perithecia of Blumeria graminis f. sp. tritici from senescing wheat leaves were collected by cooperators from 17 states. Ascospores were discharged from perithecia and single-spore isolates were characterized for virulence genes using a differential host series containing 15 known resistance genes. A total of 520 isolates from 17 states were characterized in 1993 and 1994. Virulence frequencies and complexity and racial composition were examined. The data were analyzed for associations among sets of virulence genes and the geographical distribution of phenotypes. Virulence to Pm3c, Pm3f, pm5, Pm6, and Pm7 was present in all states surveyed. Since 1990, virulence to Pm3a has increased in the northeast, and virulence to Pm1, Pm4b, Pm8, and Pm17 has increased across the area surveyed. The resistance genes Pm12 and Pm16 remain highly effective in the southeastern United States. An increase in virulence frequencies and complexity of isolates was observed.

scholarly journals PmLX66 and PmW14: New Alleles of Pm2 for Resistance to Powdery Mildew in the Chinese Winter Wheat Cultivars Liangxing 66 and Wennong 14

Plant Disease ◽  
2015 ◽  
Vol 99 (8) ◽  
pp. 1118-1124 ◽  
Author(s):  
Yanling Sun ◽  
Jingwei Zou ◽  
Huigai Sun ◽  
Wei Song ◽  
Xiaoming Wang ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Winter Wheat ◽  
Northern China ◽  
Blumeria Graminis ◽  
Wheat Cultivars ◽  
Winter Wheat Cultivars ◽  
Allelism Tests ◽  
The Relationship ◽  
Dominant Genes ◽  
New Alleles

Wheat powdery mildew (caused by Blumeria graminis f. sp. tritici) can be effectively managed by growing resistant cultivars. ‘Liangxing 66’ and ‘Wennong 14’ are the current winter wheat cultivars grown in northern China where powdery mildew is epidemic. Both cultivars have been demonstrated to carry single dominant genes for resistance to powdery mildew, tentatively designated PmLX66 and PmW14, on chromosome 5DS and share common linked markers with Pm2. Allelism tests were performed using a total of 15,657 plants of F2 segregating populations to determine the relationship between PmLX66, PmW14, and Pm2. All progeny from the crosses Liangxing 66 × ‘Ulka/8*Chancellor’ (Ulka/8*Cc), Wennong 14 × Ulka/8*Cc, and Liangxing 66 × Wennong 14 were resistant when tested with B. graminis f. sp. tritici isolate E20, indicating that PmLX66 and PmW14 are allelic to Pm2 and to each other. Liangxing 66 was resistant to 76.7% of the 60 B. graminis f. sp. tritici isolates from northern China, a slightly smaller proportion than Ulka/8*Cc (78.3%). However, Wennong 14 (85.0%) was more resistant against this set of B. graminis f. sp. tritici isolates than Ulka/8*Cc and Liangxing 66. Liangxing 66 and Wennong 14 differed from Ulka/8*Cc in respect to a number of B. graminis f. sp. tritici isolates. Based on these findings, PmLX66 and PmW14 are new alleles at the Pm2 locus.

scholarly journals Variability of the wheat powdery mildew pathogen Blumeria graminis f. sp. tritici in the 2003 crop season

2005 ◽  
Vol 30 (4) ◽  
pp. 420-422 ◽  
Author(s):  
Leila M. Costamilan
Keyword(s):  
Triticum Aestivum ◽  
Powdery Mildew ◽  
Resistance Genes ◽  
Genetic Resistance ◽  
Blumeria Graminis ◽  
Wheat Cultivars ◽  
Crop Season ◽  
Grain Yields ◽  
Wheat Powdery Mildew ◽  
Powdery Mildew Pathogen

Wheat (Triticum aestivum) powdery mildew, caused by the biotrophic fungus Blumeria graminis f. sp. tritici, is one of the most severe foliar diseases attacking this crop, reducing grain yields by 10% to 62% in Brazil. The disease can be controlled by genetic resistance of the host, but the pathogen has physiological specialization, which enables it to infect wheat cultivars that have remained resistant for years. The objective of this work was to evaluate the variability of pathogenic strains of B. graminis f. sp. tritici collected in Brazil and the effectiveness of wheat resistance genes to powdery mildew in the 2003 crop season. Plants of a differential series were inoculated with each monopustular isolate. Thirty-one combinations of effective and ineffective resistance genes were identified. Only the gene Pm4a+... remained totally effective to all isolates, and gene Pm6 was highly effective (below 10% of susceptibility), whereas genes Pm3a and Pm8 were totally ineffective (susceptible to all isolates). Genes Pm3c, D1, and D2 showed low effectiveness (above 50% of susceptibility), and genes Pm1, 2, 4a, 1+?, and 2+Mld had mean effective results to most strains (susceptibility between 10% and 49%). The virulence formula Pm1, 3c, 4a, 6, 1+?, 2+Mld, 4a+..., D2 (effective genes) / 2, 3a, 8, D1 (ineffective genes) was most frequently found, accounting for 15% of the occurrences. The most frequent number of ineffective genes was seven, ranging from three to ten.

Sign in / Sign up

Export Citation Format

Share Document