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Phylogenetic analysis of sequences of the internal transcribed spacer region of the ribosomal DNA of Septoria passerinii, Mycosphaerella graminicola and other fungi in the Dothideales. All bootstrap values above 90% are indicated.
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Citations
... ( Eyal et al., 1987;Eyal 1999;Davari et al., 2012;Brown et al., 2015) ( Gilchrist et al., 1999;Kia et al., 2017a) . ...
... Four Stb resistance genes for leaf blotch resistance have been registered ( MCINTOSH et al. 1998). In the CIMMYT breeding program three main groups of resistance sources were successfully used: (a) Russian winter wheat lines, (b) lines from the Southern Cone of South America and (c) to lesser extent also lines from the USA ( GILCHRIST et al. 1999). Resistance to leaf blotch is present in the cvs Bezostaya 1, Anza, Bobwhite and in the synthetic hexaploid lines from the cross Triticum durum × Triticum tauschii (VAN GINKEL & RAJARAM 1999). ...
Achievements and prospects of wheat breeding for disease resistance in the world and in the Czech Republic are reviewed. Attention is paid to rusts, powdery mildew, leaf blotch, glume blotch, tan spot, fusarium head blight, common and dwarf bunt, eyespot, barley yellow dwarf virus on wheat and wheat dwarf virus. Genes for resistance to rusts and powdery mildew in the cultivars registered in the Czech Republic are listed. Promising resistance genes and sources of resistance to the above mentioned diseases are reviewed. Prospects of resistance breeding including application of methods of molecular genetics and development of synthetic hexaploids are outlined.
... Two bread wheat cultivars, Boolani and Bezostaya-1, were used to assess the aggressiveness of Z. tritici isolates. Boolani is highly susceptible to STB (Abrinbana et al., 2012); however, Bezostaya-1 is considered as moderately resistant to the disease (Gilchrist et al., 1999). ...
Zymoseptoria tritici, the causal agent of Septoria tritici blotch, has emerged and evolved as a pathogen on wheat in the Fertile Crescent. Iran is located in this region, and study on the ancient pathogen populations in the country can improve our understanding on adaptive potential of aggressiveness, the role of local adaptation in shaping population structure and the involvement of selection and genetic drift in favouring aggressiveness adaptation to environments. To this aim, three aggressiveness components including days until first lesion (DUFL), days until first pycnidia (DUFP) and percentage of leaf area covered by pycnidia, in five populations of the pathogen collected from different provinces of Iran were compared in greenhouse conditions. All populations except for Golestan showed high within-population diversity for the examined traits. No difference in aggressiveness components was found between fungal collections from Khuzestan and Fars; however, significant variation was evident among the populations originated from other provinces. Comparisons of estimated QST values to FST indicated that genetic differentiation in pycnidial coverage has been the result of selection imposed by different variables; however, the divergence found for DUFL and DUFP has been achieved by genetic drift. The possible mechanisms involved in aggressiveness diversity of the pathogen populations and the impact of these findings on breeding programs for quantitative resistance are discussed.
... Breeding for host resistance for STB disease is difficult due to the low heritability of non-specific resistance, lack of knowledge on the pathogen virulence spectrum, and scarcity of durable resistant source (Eyal 1999). Under field conditions, evaluation of wheat for resistance to STB is challenged by the variation in the environment, amount of natural inoculum, and competition between pathogen causing foliar diseases for healthy tissue to infect and colonize the plant (Gilchrist et al. 1999). Additionally, STB disease is seen as mixed infection with other leaf spotting diseases, making phenotypic evaluation difficult and erroneous. ...
Septoria tritici blotch (STB) caused by Mycosphaerella graminicola, is one of the most de-structive foliar diseases of wheat (Triticum aestivum L.) especially in temperate and humid re-gions across the world. The susceptibility of recently released varieties, evolution of resistance to fungicides and increasing incidence of STB disease emphasizes the need to understand the genetics of resistance to this disease and to incorporate host resistance into adapted cultivars. This study aimed to decipher the genetics and map the resistance to STB using a recombinant inbred line (RIL) mapping population derived from 'Steele-ND' (susceptible parent) and 'ND 735' (resistant parent). The RILs were evaluated in three greenhouse experiments, using a North Dakota (ND) isolate of STB pathogen. The mean disease severity of parental genotypes, 'ND 735' (11.96%) and 'Steele-ND' (66.67%) showed significant differences (p < 0.05). The population segregated for STB and the frequency distribution of RILs indicated quantitative inheritance for resistance. The mean disease severity in RILs ranged from 0 to 71.55% with a mean of 21.98%. The genome map of this population was developed using diversity array technology (DArT) and simple sequence repeat (SSR) markers. The framework linkage map of this population was developed using 469 molecular markers. This map spanned a total dis-tance of 1,789.3 cM and consisted of 17 linkage groups. QTL mapping using phenotypic data and the framework linkage maps detected three QTL through composite interval mapping. One QTL was consistently detected in all experiments on the long arm of chromosome 5B, and explained up to 10.2% phenotypic variation. The other two QTLs, detected in single environ-ments, were mapped to 1D and 7A and explain 13% and 5.5% of the phenotypic variation, re-spectively. The map position of the consistent QTL on 5BL coincides with the map position of durable resistance gene Stb1 suggesting the importance of this region of 'ND 735' as a source of durable STB resistance for the wheat germplasm.
... Here, it was not detected at all, indicating that expression of Stb10 is sensitive to unknown environmental or developmental factors. Stb10 is probably not important in Europe, but may be significant elsewhere, as KK and its progenitors Frontana and Mentana, which are also resistant to IPO94269 (Chartrain et al., 2004b), are sources of resistance in international spring wheat breeding (Gilchrist et al., 1999). Knowledge of the conditions in which Stb10 is expressed is needed to determine its value in agriculture. ...
From a total of 238 European cultivars and breeding lines screened for isolate-specific resistance to septoria tritici blotch (STB) with eight Mycosphaerella graminicola isolates from five different countries, 142 lines were resistant to Ethiopian isolate IPO88004, and 43 lines were specifically resistant to IPO323, with little or no leaf area bearing pycnidia of M. graminicola. These lines probably all have the resistance gene Stb6. Specific resistances to isolates CA30JI, IPO001, IPO89011, IPO92006 and ISR398 were less common. Seventy-three per cent of the lines were specifically resistant to at least one isolate and 36 lines were resistant to more than one isolate. The line with the greatest number of specific resistances was the spring cultivar Raffles, with five. The most resistant line in which no specific resistance was identified was the Italian landrace Rieti, an ancestor of many modern European wheat cultivars. There was also a wide range of partial resistance among the lines tested, expressed in detached seedling leaves. Information about the resistance of wheat lines to M. graminicola isolates will assist breeders to choose parents of crosses from which progeny with superior resistance to STB may be selected.
... Frontana (17), both of which are themselves sources of resistance to STB. KK was first used in CIMMYT breeding programs in the 1970s (22). Several seedling and detached leaf studies showed that KK was resistant to many isolates of M. graminicola but susceptible to others (17,19,(30)(31)(32). ...
ABSTRACT The International Maize and Wheat Improvement Center (CIMMYT), Mexico, germplasm-derived wheat (Triticum aestivum) Kavkaz-K4500 L.6.A.4 (KK) is one of the major sources of resistance to Septoria tritici blotch (STB). KK is resistant to STB in field conditions in the UK even though a large majority of Mycosphaerella graminicola isolates are virulent to it. The genetics of the resistance of KK to four isolates of M. graminicola were investigated. KK has at least five isolate-specific resistance genes including Stb6 on chromosome 3A plus a second gene for resistance to isolate IPO323, two genes on chromosome 4A, both in the region where Stb7 is located with one designated as Stb12, and a gene designated Stb10 on chromosome 1D. Taken together, the widespread use of KK as a source of resistance to STB, its high resistance in field conditions, and its high susceptibility to M. graminicola isolates, which are virulent to all its resistance genes, suggest that high levels of field resistance to STB might be achieved by pyramiding several isolate-specific resistance genes.
... On each occasion appropriate resistant and susceptible lines were used as controls, as well as the (Wilson, 1985). Important source of resistance Catbird CIMMYT Used as source of resistance by CIMMYT (Dubin & Rajaram, 1996;Gilchrist et al., 1999 CIMMYT Major source of resistance and very resistant in the field. Specific resistance to IPO323 (Kema et al., 1996a;Eyal, 1999;Brown et al., 2001 (Wilson, 1985;Kema et al., 1996a;Brown et al., 2001) isolate IPO92006. ...
... Catbird had three isolatespecific resistances but, like KK, was very susceptible to several isolates. Again, its resistance in the field (Gilchrist et al., 1999) probably depends on isolate-specific resistance, not partial resistance. ...
Twenty-four wheat cultivars and breeding lines were screened for isolate-specific resistance to septoria tritici blotch (STB) caused by 12 isolates of Mycosphaerella graminicola. New isolate-specific resistances that could be used in wheat breeding were identified. Major sources of resistance to STB used in world breeding programmes for decades, such as Kavkaz-K4500, Veranopolis, Catbird and TE9111, have several isolate-specific resistances. This suggests that ‘pyramiding’ several resistance genes in one cultivar may be an effective and durable strategy for breeding for resistance to STB in wheat. Several cultivars, including Arina, Milan and Senat, had high levels of partial resistance to most isolates tested as well as isolate-specific resistances. Resistance to isolate IPO323 was common, present in all but one of the major sources of resistance tested. This suggests that resistance to IPO323 may be an indicator of varietal resistance to STB in the field.
Co-evolution of wheat and its devastating pathogen Mycosphaerella graminicola (anamorph Septoria tritici), the causal agent of septoria tritici blotch, a foliar disease of wheat, is suggested to occur in Fertile Crescent as their center of origin and, thus, interaction between pathogen virulence and host resistance is important subject to be addressed. We have investigated resistance spectra of 54 wheat genotypes including a set of differentials carrying known resistance genes and virulence patterns of 14 M. graminicola isolates at seedling stage under controlled environmental conditions. The isolates were collected in Iran from five provinces. Diversity in virulence and aggressiveness was observed among the isolates from four provinces. Isolates collected from Golestan province were virulent to all wheat genotypes from germplasm of Iran, while specific resistances were identified to the isolates from other provinces. Among wheat genotypes, cvs. Chamran, Morvarid and Hirmand had the greatest number of specific resistances as well as partial resistance. Wheat genotypes of the differential set also differed in their reactions to the isolates. Arina, Flame and TE 9111 were specifically resistant to the greatest number of isolates from different provinces. Most isolates were virulent to the other differentials such as cvs. Shafir, Estanzuela federal and Courtot indicating that extensive adaption of virulence to most of the known resistance genes (Stb) has occurred in these regions. The new sources of resistance to highly virulent isolates from Iran may also be utilized in wheat breeding programs to develop resistant cultivars against pathogen populations in other countries.
