scholarly journals Characteristics of winter wheat genotypes with different degree of resistance to Fusarium (Fusarium ssp.) in terms of resistance to powdery mildew (Blumeria graminis)

2014 ◽  
Vol 54 (4) ◽  
Plant Disease ◽  
2009 ◽  
Vol 93 (11) ◽  
pp. 1219-1219 ◽  
Author(s):  
C. Cowger ◽  
R. Parks ◽  
D. Marshall

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.


Plant Disease ◽  
2015 ◽  
Vol 99 (8) ◽  
pp. 1118-1124 ◽  
Author(s):  
Yanling Sun ◽  
Jingwei Zou ◽  
Huigai Sun ◽  
Wei Song ◽  
Xiaoming Wang ◽  
...  

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.


Plant Disease ◽  
2021 ◽  
Author(s):  
Xiaohan Shi ◽  
Peipei Wu ◽  
Jinghuang Hu ◽  
Dan Qiu ◽  
Yunfeng Qu ◽  
...  

Winter wheat cultivar Liangxing 99, which carries gene Pm52, is resistant to powdery mildew at both seedling and adult plant stages. An F2:6 recombinant inbred line (RIL) population from cross Liangxing 99 × Zhongzuo 9504 was phenotyped with Blumeria graminis f. sp. tritici isolate Bgt27 at the adult plant stage in four field tests and the seedling stage in a greenhouse test. The analysis of bulk segregant RNA sequences identified an SNP-enriched locus, Qaprpm.caas.2B, on chromosome 2BL in the same genomic interval of Pm52 associated with the all-stage resistance (ASR) and Qaprpm.caas.7A on chromosome 7AL associated with the adult-plant resistance (APR) against the disease. Qaprpm.caas.2B was detected in a 1.3 cM genetic interval between markers Xicscl726 and XicsK128 in which Pm52 was placed with a range of LOD values from 28.1 to 34.6, and the phenotype variations explained in terms of maximum disease severity (MDS) ranged from 45% to 52%. The LOD peak of Qaprpm.caas.7A was localized in a 4.6 cM interval between markers XicsK7A8 and XicsK7A26 and explained the phenotypic variation of MDS ranging from 13% to 16%. The results of this study confirmed Pm52 for ASR and identified Qaprpm.caas.7A for APR to powdery mildew in Liangxing 99. Keywords: Triticum aestivum; Blumeria graminis f. sp. tritici; Pm52; QTL; BSR-Seq


2013 ◽  
Vol 61 (4) ◽  
pp. 247-254
Author(s):  
J. Komáromi ◽  
S. Bencze ◽  
B. Varga ◽  
G. Vida ◽  
O. Veisz

Over the last two centuries the atmospheric CO2 level has exhibited a consistent rise, leading to an increase in the greenhouse effect. This level is now 35% higher than it was before the industrial revolution. On the basis of various scenarios from the Special Report on Emissions it is expected to rise from the present level of 385 ppm to 650–970 ppm by the end of the 21st century.Plant biomass and resistance of winter wheat to various powdery mildew pathotypes were investigated at normal (400 ppm) and enhanced (700 ppm) atmospheric CO2 levels in a greenhouse. Wheat cultivars Ukrainka and Mv Hombár, and 12 lines from the mapping population developed from their cross and exhibiting different level of resistance were tested.The results showed that the atmospheric CO2 level had little influence on the resistance of winter wheat to powdery mildew infections based on the percentage of leaf area covered whole plant percentage severity. In response to higher atmospheric CO2 level there was an increase in the aboveground biomass of the winter wheat genotypes tested in the present work, leading to an increase in plant height and in stem and leaf weight. However, the number of tillers and the grain yield did not increase compared with the values recorded at normal atmospheric CO2 level.


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