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1
Teferi, Teklay A. y Muruts L. Wubshet. "Prevalence and Intensity of Barley Diseases in South Tigray, Ethiopia". International Journal of Phytopathology 6, n.º 3 (30 de diciembre de 2017): 41–45. http://dx.doi.org/10.33687/phytopath.006.03.2386.
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Barley is attacked by many diseases and hence, the study was conducted to quantify and profile barley affecting diseases for management options. The survey was based on the assessment of barley fields at 5 km interval. Results indicated that powdery mildew, leaf rust, stem rust, leaf scald, and smuts were among the important diseases in south Tigray. The prevalence of the former diseases was 60, 60, 40, 47.8, and 40%, respectively. The incidence of powdery mildew, scaled, leaf rust and stem rust was 100% in considerable fields and cultivars. The incidence of smuts was ranged from 5% to 30%. Similarly, the mean severities of powdery mildew, leaf rust, stem rust and leaf scald were 43.4, 54.5, 45 and 20%, respectively, while, smuts caused complete spike losses. Therefore, investigating of the pathogens variability especially for rusts, powdery mildew and scald as well as developing integrated management options for all diseases is of concern.
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Vahamidis, Petros, Angeliki Stefopoulou, Christina S. Lagogianni, Garyfalia Economou, Nicholas Dercas, Vassilis Kotoulas, Dionissios Kalivas y Dimitrios I. Tsitsigiannis. "Pyrenophora teres and Rhynchosporium secalis Establishment in a Mediterranean Malt Barley Field: Assessing Spatial, Temporal and Management Effects". Agriculture 10, n.º 11 (18 de noviembre de 2020): 553. http://dx.doi.org/10.3390/agriculture10110553.
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Malt barley is one of the promising crops in Greece, mainly due to high yields and contract farming, which have led to an increase in malt barley acreage. Net form net blotch (NFNB), caused by Pyrenophora teres f. teres, and barley leaf scald, caused by Rhynchosporium secalis, are among the most important barley diseases worldwide and particularly in Greece. Their occurrence in malt barley can exert a significant negative effect on malt barley grain yield and quality. An experimental trial across two growing seasons was implemented in Greece in order (i) to estimate the epidemiology of NFNB and leaf scald in a barley disease-free area when the initial inoculation of the field occurs through infected seeds, (ii) to explore the spatial dynamics of disease spread under the interaction of the nitrogen rate and genotype when there are limited sources of infected host residues in the soil and (iii) to assess the relationship among the nitrogen rate, grain yield, quality variables (i.e., grain protein content and grain size) and disease severity. It was confirmed that both NFNB and leaf scald can be carried over from one season to the next on infected seed under Mediterranean conditions. However, the disease severity was more pronounced after the barley tillering phase when the soil had been successfully inoculated, which supports the hypothesis that the most important source of primary inoculum for NFNB comes from infected host residue. Increasing the rate of nitrogen application, when malt barley was cultivated in the same field for a second year in a row, caused a non-significant increase in disease severity for both pathogens from anthesis onwards. However, hotspot and commonality analyses revealed that spatial and genotypic effects were mainly responsible for hiding this effect. In addition, it was found that the effect of disease infections on yield, grain size and grain protein content varied in relation to the genotype, pathogen and stage of crop development. The importance of crop residues in the evolution of both diseases was also highlighted.
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Karjalainen, Reijo. "Yield reduction of spring barley in relation to disease development caused by Rhynchosporium secalis". Agricultural and Food Science 62, n.º 3 (1 de julio de 1990): 245–54. http://dx.doi.org/10.23986/afsci.72931.
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Effects of barley scald caused by Rhynchosporium secalis on grain yield were studied in three spring barley cultivars under field conditions using artificial inoculation over three years. The disease strongly reduced the green-leaf area duration compared with fungicide-treated leaves. At low infection level, R. secalis reduced the grain yield of barley by 3—5 %. Moderate and severe infection reduced the grain yields of susceptible cultivars by 10—12 %. Single-tiller analysis of yield components indicated that grain weight and ear weight were most affected, but the number of grains was only insignificantly reduced by the disease. Implications of these results for controlling scald disease in Finland are discussed.
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Cheong, Judy, Kevin Williams y Hugh Wallwork. "The identification of QTLs for adult plant resistance to leaf scald in barley". Australian Journal of Agricultural Research 57, n.º 9 (2006): 961. http://dx.doi.org/10.1071/ar05389.
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Barley leaf scald disease, caused by the fungal pathogen Rhynchosporium secalis, can be economically damaging, causing both yield losses and lower quality from reduced grain size. Most genetic studies of scald resistance have concentrated on seedling reactions either because of a lack of access to field screening resources or else because of the more definitive phenotype obtained at the seedling stage. However, understanding the genetics of adult plant resistance (APR) to leaf scald could help to produce more durable resistance to this disease. APR to leaf scald in a Chebec/Harrington population (120 doubled haploid (DH) lines) and a Mundah/Keel population (95 DH lines) was determined at Turretfield, South Australia, in 2004. Two different conditions of scald infection were used for Chebec/Harrington, natural infection and inoculation with 2 known scald isolates, whereas Mundah/Keel was inoculated with 2 known isolates. Quantitative trait loci (QTLs) for scald resistance were identified using a previously published Chebec/Harrington map. Three QTLs (on chromosomes 7HS, 7HL, and 6HS) were identified using the natural infection data and one QTL on chromosome 6HL using the inoculated plant data. Two QTLs were identified on chromosome 3HL and 6HS, respectively, using a partial map of Mundah/Keel. An unmapped Schooner/O’Connor population, consisting of 116 DH lines, was also phenotyped for adult plant resistance to scald using natural infection at Turretfield in 2001. Bulked-segregant analysis was used to identify molecular markers linked to a scald resistance locus in the barley cultivar O’Connor on chromosome 6HS, at the same location as the QTLs identified from Harrington and Keel. Six of the QTLs for APR to leaf scald identified in this study were co-located with previously identified seedling resistance genes.
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Daba, Sintayehu D., Richard Horsley, Robert Brueggeman, Shiaoman Chao y Mohsen Mohammadi. "Genome-wide Association Studies and Candidate Gene Identification for Leaf Scald and Net Blotch in Barley (Hordeum vulgare L.)". Plant Disease 103, n.º 5 (mayo de 2019): 880–89. http://dx.doi.org/10.1094/pdis-07-18-1190-re.
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We report genomic regions that significantly control resistance to scald, net form (NFNB) and spot form net blotch (SFNB) in barley. Barley genotypes from Ethiopia, ICARDA, and the United States were evaluated in Ethiopia and North Dakota State University (NDSU). Genome-wide association studies (GWAS) were conducted using 23,549 single nucleotide polymorphism (SNP) markers for disease resistance in five environments in Ethiopia. For NFNB and SFNB, we assessed seedling resistance in a glasshouse at NDSU. A large proportion of the Ethiopian landraces and breeding genotypes were resistant to scald and NFNB. Most of genotypes resistant to SFNB were from NDSU. We identified 17, 26, 7, and 1 marker-trait associations (MTAs) for field-scored scald, field-scored net blotch, greenhouse-scored NFNB, and greenhouse-scored SFNB diseases, respectively. Using the genome sequence and the existing literature, we compared the MTAs with previously reported loci and genes for these diseases. For leaf scald, only a few of our MTAs overlap with previous reports. However, the MTAs found for field-scored net blotch as well as NFNB and SFNB mostly overlap with previous reports. We scanned the barley genome for identification of candidate genes within 250 kb of the MTAs, resulting in the identification of 307 barley genes for the 51 MTAs. Some of these genes are related to plant defense responses such as subtilisin-like protease, chalcone synthase, lipoxygenase, and defensin-like proteins.
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Legge, W. G., D. R. Metcalfe, A. W. Chiko, J. W. Martens y A. Tekauz. "Reaction of Turkish barley accessions to Canadian barley pathogens". Canadian Journal of Plant Science 76, n.º 4 (1 de octubre de 1996): 927–31. http://dx.doi.org/10.4141/cjps96-155.
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Recent changes in the virulence patterns of Canadian barley pathogens have necessitated the search for new sources of genetic resistance in barley. Evaluation of 176 Turkish barley accessions for disease reaction to barley pathogens prevalent in Canada indicated that this germplasm is a good source of resistance to Septoria passerinii, Rhynchosporium secalis and the spot-form of Pyrenophora teres, but not to Cochliobolus sativus (spot blotch phase), Puccinia graminis tritici, Ustilago nuda or barley stripe mosaic virus. A small number of accessions with resistance to the net-form of P. teres were identified. Key words:Hordeum vulgare, barley, disease resistance, net blotch, scald, speckled leaf blotch
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Jalli, Marja, Janne Kaseva, Björn Andersson, Andrea Ficke, Lise Nistrup-Jørgensen, Antanas Ronis, Timo Kaukoranta, Jens-Erik Ørum y Annika Djurle. "Yield increases due to fungicide control of leaf blotch diseases in wheat and barley as a basis for IPM decision-making in the Nordic-Baltic region". European Journal of Plant Pathology 158, n.º 2 (28 de julio de 2020): 315–33. http://dx.doi.org/10.1007/s10658-020-02075-w.
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Abstract Fungal plant diseases driven by weather factors are common in European wheat and barley crops. Among these, septoria tritici blotch (Zymoseptoria tritici), tan spot (Pyrenophora tritici-repentis), and stagonospora nodorum blotch (Parastagonospora nodorum) are common in the Nordic-Baltic region at variable incidence and severity both in spring and winter wheat fields. In spring barley, net blotch (Pyrenophora teres), scald (Rhynchosporium graminicola, syn. Rhynchosporium commune) and ramularia leaf spot (Ramularia collo-cygni) are common yield limiting foliar diseases. We analysed data from 449 field trials from 2007 to 2017 in wheat and barley crops in the Nordic-Baltic region and explored the differences in severity of leaf blotch diseases between countries and years, and the impact of the diseases on yield. In the experiments, septoria tritici blotch dominated in winter wheat in Denmark and southern Sweden; while in Lithuania, both septoria tritici blotch and tan spot were common. In spring wheat, stagonospora nodorum blotch dominated in Norway and tan spot in Finland. Net blotch and ramularia leaf blotch were the most severe barley diseases over large areas, while scald occurred more locally and had less yield impact in all countries. Leaf blotch diseases, with severity >50% at DC 73–77, caused an average yield loss of 1072 kg/ha in winter wheat and 1114 kg/ha in spring barley across all countries over 5 years. These data verify a large regional and yearly variation in disease severity, distribution and impact on yield, emphasizing the need to adapt fungicide applications to the actual need based on locally adapted risk assessment systems.
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Çelik Oğuz, Arzu y Aziz Karakaya. "Genetic Diversity of Barley Foliar Fungal Pathogens". Agronomy 11, n.º 3 (27 de febrero de 2021): 434. http://dx.doi.org/10.3390/agronomy11030434.
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Powdery mildew, net blotch, scald, spot blotch, barley stripe, and leaf rust are important foliar fungal pathogens of barley. Fungal leaf pathogens negatively affect the yield and quality in barley plant. Virulence changes, which can occur in various ways, may render resistant plants to susceptible ones. Factors such as mutation, population size and random genetic drift, gene and genotype flow, reproduction and mating systems, selection imposed by major gene resistance, and quantitative resistance can affect the genetic diversity of the pathogenic fungi. The use of fungicide or disease-resistant barley genotypes is an effective method of disease control. However, the evolutionary potential of pathogens poses a risk to overcome resistance genes in the plant and to neutralize fungicide applications. Factors affecting the genetic diversity of the pathogen fungus may lead to the emergence of more virulent new pathotypes in the population. Understanding the factors affecting pathogen evolution, monitoring pathogen biology, and genetic diversity will help to develop effective control strategies.
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Abbott, DC, JJ Burdon, AM Jarosz, AHD Brown, WJ Muller y BJ Read. "The relationship between seedling infection types and field reactions to leaf scald in Clipper barley backcross lines". Australian Journal of Agricultural Research 42, n.º 5 (1991): 801. http://dx.doi.org/10.1071/ar9910801.
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Eighty-four third backcross (BC) lines of barley with different chromosomal segments of Hordeum spontaneum in a H. vulgare (cv. Clipper) background, were tested for resistance to a mixture of isolates of Rhynchosporium secalis using a seedling assay. Twelve of the lines were classed as resistant, including two which segregated for resistance. Plants tested using the seedling assay were subsequently planted in the field in Canberra and levels of disease monitored through to plant maturity. Seedling assay scores and field disease levels were closely correlated (r = 0.72, P < 0.001). Furthermore, grain yields for resistant BC-lines were 25% higher, on average, than those for susceptible lines. A separate field trial containing a selection of these lines was conducted in a scald-prone barley growing area (Wagga Wagga). The results obtained were consistent with those from the Canberra trial. The experiments demonstrate that resistances to leaf scald in H. spontaneum, first detected as seedling response types, also function to increase the resistance of barley throughout the growing season.
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Cromey, M. G., R. C. Butler, C. A. Munro y S. E. Ebdon. "Effects of disease resistance and fungicide treatments on scald and yield in four barley cultivars". New Zealand Plant Protection 53 (1 de agosto de 2000): 93–96. http://dx.doi.org/10.30843/nzpp.2000.53.3619.
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New Zealand barley cultivars differ in resistance to leaf scald caused by Rhynchosporium secalis Four cultivars (one highly resistant two moderately resistant and one susceptible) were selected for evaluation in a field trial under differing fungicide regimes Fungicide applications were used to encourage no epidemic (early late fungicide applications) an early epidemic (late applications only) a late epidemic (early applications only) or a full epidemic (no applications) Disease severity was assessed six times The resistant cultivar Dash was virtually free of scald at all assessment dates Disease progressed rapidly in untreated plots of the susceptible cultivar Optic from the first appearance of scald (13 August) until all leaves were fully diseased (midNovember) Fungicide applications reduced scald severity in Optic but did not eliminate the disease The two moderately resistant cultivars had intermediate disease levels Yields reflected relative disease severity with the greatest yield differences between full and no disease control being recorded in Optic Control of the late epidemic increased yield to a much greater extent than the early epidemic
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Khan, TN y KJ Young. "Effects of fungicide seed dressings and fungicide-treated fertiliser on the severity of leaf diseases and yield of barley in Western Australia". Australian Journal of Experimental Agriculture 29, n.º 4 (1989): 565. http://dx.doi.org/10.1071/ea9890565.
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Standard and increased rates of seed dressings with triadimenol, flutriafol and experimental formulations of flutriafol, and triadimefon and flutriafol coated on double superphosphate and drilled at sowing were assessed for control of leaf diseases of barley (Hordeum vulgare L. cv. Stirling). Scald, (Rhynchosporium secalis (Oud.) Davis), powdery mildew (Erysiphe graminis f. sp. hordei March.) and Drechslera verticillata (O'Gara) Shoem. appeared in various experiments. Fungicide-coated fertilisers provided the most disease control for the longest duration, triadimefon coated fertiliser increasing yield by up to 30%. Fungicide-treated fertilisers therefore show great promise in increasing the level and duration of disease control as well as the yield of barley where foliar diseases are known to be a problem.
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Khan, TN. "Effects of stubble-borne fungal inoculum on incidence of leaf diseases and yields of barley in Western Australia". Australian Journal of Experimental Agriculture 28, n.º 4 (1988): 529. http://dx.doi.org/10.1071/ea9880529.
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Effect of stubble residues on leaf diseases and yield of barley (Hordeum vulgare L. cv. Dampier) were studied by adding small quantities of infested stubble to test plots grown on land where a non-barley crop or pasture had been grown in the previous year. Experiments conducted at 5 locations in 198 1 and 1982 showed that stubble residues increased leaf disease. The severity of leaf disease varied with location and year. High levels of scald (Rhynchosporium secalis) were recorded at all locations, but substantial levels of net blotch (Drechslera teres) occurred only at northern locations. Halo spot (Selenophoma donacis) and a leaf spot caused by Drechslera verticillata were either absent or occurred in minor proportions. The incidence of powdery mildew (Erysiphe graminis f.sp. hordei) at Mt Barker in 1982 was not related to the presence of stubble residues. Grain yield losses of 9 and 28% occurred in the stubble amended plots in 1981 and 1982, respectively. Reductions in number of heads and number of seeds per plot appeared to be the major components of yield loss.
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Read, B. J., H. Raman, G. McMichael, K. J. Chalmers, G. A. Ablett, G. J. Platz, R. Raman et al. "Mapping and QTL analysis of the barley population Sloop × Halcyon". Australian Journal of Agricultural Research 54, n.º 12 (2003): 1145. http://dx.doi.org/10.1071/ar03037.
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A genetic linkage map of Hordeum vulgare L. 1280 cM in length, composed of 257 AFLP, RFLP, SNP, and microsatellite markers, has been constructed. The map was based on a doubled haploid population made from the cross Sloop (spring type) × Halcyon (winter type). The genetic map was used to identify qualitative major genes and quantitative trait loci (QTLs) affecting traits related to growth and flowering, grain colour, and disease resistance. Nine QTLs associated with grain colour (brightness, redness, yellowness, blue aleurone colour), plant height, 'intrinsic lateness', awn emergence, response to photoperiod, and spring or winter habit were located on 1H, 2H, 3H, 4H, and 5H. Eight QTLs associated with resistance to scald, net form of net blotch, leaf rust and powdery mildew were identified on chromosomes 1H, 2H, 3H, 4H, 5H, and 7H. The estimated magnitude of the QTL effects ranged from 9 to 85% of the total phenotypic variance. Resistances to leaf scald, net blotch, and leaf rust, and photoperiod and grain colour, were each controlled by at least one major gene.
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Jefferies, S. P., A. R. Barr, C. Hunt y R. D. Wheeler. "Agronomic and breeding value of genes for resistance to leaf scald (Rhynchosporium secalis) in barley (Hordeum vulgare)". Australian Journal of Agricultural Research 51, n.º 8 (2000): 955. http://dx.doi.org/10.1071/ar00038.
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Scald (Rhynchosporium secalis) is one of the most damaging leaf and stem diseases of barley grown in southern Australia. The development of resistant cultivars is the most effective means of controlling scald. However, the highly variable nature of the scald pathogen has often resulted in resistance conferred by single major genes being rendered ineffective. Breeding and selection for non-race specific, durable resistance, or the adoption of major gene deployment strategies such as gene pyramiding, could largely overcome this problem. Four cultivars of barley (Guardian, Halcyon, Sultan, Waveney) were evaluated as potential sources of scald resistance, suitable for gene introgression and pyramiding programs in southern Australia. Each of these prospective donor parents was backcrossed to the susceptible recurrent parent Sloop through one cycle of backcrossing. All 4 cultivars were resistant to scald isolates common in southern Australia. No factors, either deleterious or beneficial to grain yield, were associated with scald resistance genes from Guardian, Halcyon, and Waveney. Scald resistance genes carried by Sultan were found to be associated with lower grain yield. Both resistant and susceptible first backcross lines derived from Guardian produced a lower proportion of plump grain than the recurrent parent Sloop. A greater number of backcrosses and large population size may be required to successfully introgress scald resistance genes from Sultan and Guardian into germplasm adapted to southern Australian conditions. The development of molecular markers linked to resistance genes in these parents will allow efficient introgression and pyramiding of scald resistance genes from Waveney, Halcyon, and Sultan.
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Kavak, Hamit. "Effects of different sowing times on leaf scald and yield components of spring barley under dryland conditions". Australian Journal of Agricultural Research 55, n.º 2 (2004): 147. http://dx.doi.org/10.1071/ar02058.
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The effect of sowing date on severity of scald and yield components of barley was studied over 2 years, using 15-day intervals between sowing dates under dryland conditions in Turkey. Disease severity was greatest at the first sowing time, and it decreased linearly at subsequent sowing times in both years. Disease did not develop on flag and second leaves for the third sowing date, and was not observed on any leaf after the fourth and fifth dates of sowing in 2000 and 2001, respectively. After the third sowing date, a decrease in total grain yield and yield components, number of ears per plant, grains per head, and plant height was observed in both infected and control plots. Yield was also reduced by scald and resulted in total grain yield reductions of 10.1% and 6.0% for the first and second sowing dates in 2000, and 16.2%, 9.2%, and 3.0% on the first 3 sowing dates in 2001, respectively. At the first 2 sowing dates only ears per plant was decreased by scald, with respective reductions of 8.3% and 4.4% in 2000, and 14.3% and 8.5% in 2001, when compared with the control plots.
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Loughman, R. y TN Khan. "Effect of fungicide seed dressings on leaf stripe of barley caused by Pyrenophora graminea S. Ito Kuribay". Australian Journal of Experimental Agriculture 33, n.º 4 (1993): 465. http://dx.doi.org/10.1071/ea9930465.
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Eight fungicide seed dressings were evaluated in the southern cereal belt of Western Australia for control of barley leaf stripe caused by Pyrenophora graminea. Flutriafol (100 �g/g seed) and triadimenol plus imazalil (225 + 75 �g/g seed) were most effective. Control of leaf stripe with other fungicides depended on location. Imazalil appeared to be the ingredient most active against leaf stripe. Flutriafol and triadimenol plus imazalil offer effective control of leaf stripe and other endemic diseases (loose smut, powdery mildew, and scald) in the southern cereal belt.
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Ríos, Melina Ocampo, Paula Fernández y Marcelo Carmona. "Detection of Rhynchosporium secalis in barley seeds from Argentina through polymerase chain reaction technique". Fitopatologia Brasileira 32, n.º 5 (octubre de 2007): 415–18. http://dx.doi.org/10.1590/s0100-41582007000500007.
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Leaf scald of barley caused by Rhynchosporium secalis is an important disease in Argentina. The fungus is a necrotrophic pathogen which survives in stubble, seeds and weeds. Isolation of R. secalis from seeds on artificial media usually has not been successful due to the slow growth rate of the pathogen and strong inhibition by contaminants. The objective in this work was to detect R. secalis in different genotypes of barley seeds in Argentina using the polymerase chain reaction (PCR)-based diagnostic assay. Four barley genotypes were tested in 2004: Quilmes Ayelén, Quilmes Alfa, Barke and Maltería Pampa 1004. The previously described RS8 and RS9 primers were used for the detection of R. secalis in barley seeds. A 264-bp single band was obtained for each cultivar showing the presence of R. secalis. The use of specific primers was efficient in the detection of R. secalis in barley seeds in Argentina and could be used for routine diagnosis, epidemiology and seed transmission studies. This is the first report on the detection of R. secalis in barley seeds in Argentina.
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Germán S, E. "Breeding Malting Barley under Stress Conditions in South America". Czech Journal of Genetics and Plant Breeding 40, No. 4 (23 de noviembre de 2011): 140–47. http://dx.doi.org/10.17221/3713-cjgpb.
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The annual average area sown with barley (Hordeum vulgare) in South America during 1999–2003 was 795 000 ha. In Argentina, Brazil, Chile and Uruguay, two-rowed spring cultivars are used mostly for malt production. Research has been developed in private malting companies and official institutions supported by the industry. In Argentina, tolerance to drought and heat stress during grain filling are important in drier areas. Yield and malt extract had been improved in cultivars released from 1940 to 1998. In Brazil, progress in grain yield, grain size, malting quality, early maturity, and resistance to net blotch, powdery mildew, and leaf rust has been achieved by EMBRAPA and malting companies. Higher tolerance to soil acidity and resistance to spot blotch are required. Since 1976, malting barley breeding in INIA-Chile has improved grain yield, grain size, beer production efficiency, and resistance to scald, net blotch, stripe rust, and leaf rust. Uruguay produces high quality malt exported mainly to Brazil. Malting companies have released locally bred and introduced cultivars since the early 1970’s. Initiated in 1988, INIA-Uruguay breeding program has improved yield, malting quality, and lodging and disease resistance. Fusarium head blight is a new challenge for research in Brazil and Uruguay. Information regarding malting barley production, the most important stresses in different areas of production, and breeding progress under South American conditions is provided.
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Willsmore, Kerrie L., Paul Eckermann, Rajeev K. Varshney, Andreas Graner, Peter Langridge, Margaret Pallotta, Judy Cheong y Kevin J. Williams. "New eSSR and gSSR markers added to Australian barley maps". Australian Journal of Agricultural Research 57, n.º 9 (2006): 953. http://dx.doi.org/10.1071/ar05384.
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To enhance genetic maps of barley previously developed in Australia for identifying markers useable in molecular breeding, a new set of simple sequence repeat (SSR) and indel markers was added to the maps. These markers were developed through (i) database mining of barley expressed sequence tag (EST) sequences, (ii) comparative barley-rice genome analysis, and (iii) screening of a genomic library with SSR probes. The primer set selected for this study comprised 216 EST-SSR (eSSR) and 25 genomic SSR (gSSR) markers, which were screened for polymorphism on 4 doubled haploid (DH) or recombinant inbred line (RIL) populations. In total, 81 new markers were added to the maps, with good coverage on all 7 chromosomes, except 6H, which only had 2 new markers added. The marker order of previously published maps was re-evaluated by comparing recombination fractions calculated by 2 methods to discover the best position for each marker. The new SSR markers were then added to the updated maps. Several of these new markers are linked to important barley disease resistance genes such as those for cereal cyst nematode, spot form of net blotch, and leaf scald resistance, and are readily useable for marker-assisted barley breeding. The new maps are available on-line at www.genica.net.au.
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Gamba, F. y A. Tekauz. "First Report of a Leaf Spot of Barley Caused by Drechslera gigantea in Uruguay". Plant Disease 87, n.º 1 (enero de 2003): 99. http://dx.doi.org/10.1094/pdis.2003.87.1.99b.
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Barley (Hordeum vulgare), an important crop in Uruguay, is vulnerable to several foliar diseases. In early November 2001, leaves displaying unusual lesions were observed in a commercial barley crop and research plots in the Paysandu District of western Uruguay. Lesions were small, elliptical, tan-colored to necrotic, approximately 4 × 1 mm, and had a narrow, dark brown margin. Older lesions occasionally were surrounded by a narrow (0.5 mm wide) chlorotic halo and some lesions had a white dot in the center. Sections of affected leaf tissue were placed in a moist chamber at 20°C with a 12 h light/dark cycle for 4 days to promote sporulation of a putative fungal pathogen. Conidia subsequently developing from infected tissue were large (250 to 325 μm long) and were identified as Drechslera gigantea (2). Koch's postulates were verified by growing the fungus on 10% V8 juice agar, and the aqueous suspension was adjusted to 3 × 104conidia per ml. Lower concentrations were tested but they were not great enough to prevent disease escape. A De Vilbiss atomizer was used to spray 2-week-old barley seedlings kept in a growth chamber at 18°C with a 17/7 h light/dark cycle. Inoculated plants were kept in the dark for 24 h at 100% relative humidity and then returned to the previous conditions. Twenty seedlings of each of two Canadian, one American, and eight barley genotypes from Uruguay were used for the study. The experiment was conducted twice including water controls each time. Small lesions appeared on all leaves of all inoculated plants on 10 cultivars 4 days after inoculation, and after 9 days they were fully developed and visually the same as those on plants in the field. Control plants did not display symptoms. D. gigantea was reisolated from lesions on all diseased leaves. A 0 to 5 disease infection scale, based on lesion size, was developed for which infection types 0, 1, and 2 were considered as immune, resistant, and moderately resistant phenotypes, respectively, type 3 as an intermediate phenotype, and 4 and 5 as moderately susceptible and susceptible phenotypes, respectively. The most susceptible infection type was observed on ‘Dayman’ barley, the same cultivar in which the disease was first noted and from which the pathogen was isolated. Cv. Herta, once grown in western Canada, also was susceptible, whereas the cvs. Bowman (United States) and McGwire (Canada) were moderately resistant. Only one cultivar (Uruguay) did not show any symptoms. Several Uruguayan experimental barley lines exhibited moderately resistant or intermediate phenotypes. D. gigantea has been reported as causing an “eyespot” disease on grasses (2) and rice (1). Further studies with different inoculation protocols and host development stages as well as sampling of a broader range of barley germ plasm is needed to assess the current and potential impact of this fungus. To our knowledge, this is the first report of D. gigantea as a pathogen of barley in Uruguay, and possibly the first report of this species as a barley pathogen globally. References: (1) S.-W. Ahn. Plant Dis. 64:878, 1980. (2) C. Drechsler. J. Agric. Res. 24:641,1923.
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Cope, Jonathan E., Gareth J. Norton, Timothy S. George y Adrian C. Newton. "Identifying potential novel resistance to the foliar disease ‘Scald’ (Rhynchosporium commune) in a population of Scottish Bere barley landrace (Hordeum vulgare L.)". Journal of Plant Diseases and Protection 128, n.º 4 (27 de mayo de 2021): 999–1012. http://dx.doi.org/10.1007/s41348-021-00470-x.
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AbstractBarley ‘Scald’ is an economically damaging fungal disease that is a global problem, causing significant yield and economical losses in the UK barley feed and malting industries. Presently, a limited number of Rhynchosporium resistance genes exist, but selective pressures on the fungi cause the demand for new sources of resistance. Landraces, such as the Scottish Bere barley, hold potential sources of resistance that can be utilised, with farmers providing anecdotal evidence of resistance in field populations of Bere. This study analysed 131 heritage cultivars and landrace lines, including 37 Bere lines, to screen for resistance using both detached leaf assays (DLAs) and field experiments. Results showed that Bere lines produced smaller, but more necrotic, lesions for the majority of isolates in the DLAs, as well as smaller scores when visually assessed in field conditions. Whilst the infection patterns of the lines differed between isolates and experimental conditions, three Bere lines were identified as consistently showing reduced levels of infection (45 A 23, 58 A 36 Eday, and 8-125). Using genome-wide association analysis, we were able to identify a number of genomic regions associated with reduced infection symptoms, four in regions associated with known resistance genes, but another four associated with new regions that contain promising candidate genes. Further analysis of these new regions and candidate genes should be undertaken to identify targets for future disease-resistance breeding.
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Rouse, M. N., C. A. Griffey y W. S. Brooks. "First Detection of Puccinia hordei Virulence to Barley Leaf Rust Resistance Gene Rph3 and Combination with Virulence to Rph7 in North America". Plant Disease 97, n.º 6 (junio de 2013): 838. http://dx.doi.org/10.1094/pdis-08-12-0785-pdn.
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Barley leaf rust, caused by Puccinia hordei Otth., has been problematic in United States barley (Hordeum vulgare L.) production in the Mid-Atlantic coast region and California. During the early 1990s, P. hordei pathotypes with virulence to resistance gene Rph7 caused average yield losses from 6 to 16% (3). ‘Doyce’ barley was released in 2003 and was described as being resistant to leaf rust (2). Initially in April 2010 and subsequently in spring 2011 and 2012, high severities and infection responses were observed on experimental plots of ‘Doyce’ in Warsaw and Blacksburg, Virginia. Three single uredinial isolates of P. hordei were derived from collections made from ‘Doyce’ barley. The isolates were characterized for virulence to barley leaf rust resistance genes by inoculating at least two replicates of a barley leaf rust differential set including 12 Rph genes (1). Previous methods used for inoculation, incubation, and pathotyping were followed (1). Infection types were scored on a 0 to 4 scale where 2 and below indicated resistance and 3 and above indicated susceptibility (4). The three isolates collected from Doyce barley displayed large pustules with infection types 3,3+ to cultivars Estate (Rph3) and Cebada Capa (Rph7). Avirulent isolates of P. hordei displayed infection types 0; to 0;1c to Estate and ;n to 0;1n to Cebada Capa (1). The data indicated that all three isolates were virulent to both barley leaf rust resistance genes Rph3 and Rph7. Though combined Rph3 and Rph7 virulence has been reported in the Mediterranean region, this is the first report of Rph3 virulence in North America. These isolates of P. hordei are virulent to important sources of resistance to barley leaf rust and threaten barley production in environments conducive for disease development in North America. References: (1) W. S. Brooks et al. Phytopathology 90:1131, 2000. (2) W. S. Brooks et al. Crop Sci. 45:792, 2005. (3) C. A. Griffey et al. Plant Dis. 78:256, 1994. (4) M. N. Levine and W. J. Cherewick. U.S. Dept. Agric. Tech. Bull. 1056, 1952.
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Fetch, T. G., B. J. Steffenson y E. Nevo. "Diversity and Sources of Multiple Disease Resistance in Hordeum spontaneum". Plant Disease 87, n.º 12 (diciembre de 2003): 1439–48. http://dx.doi.org/10.1094/pdis.2003.87.12.1439.
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Hordeum spontaneum, the progenitor of cultivated barley, is known to be a rich source of disease resistance genes. The objective of this study was to assess the diversity of H. spontaneum accessions from Israel and Jordan for their reaction to six fungal pathogens of importance to cultivated barley in the United States and Canada. Overall, a high level of macro-scale (across collection sites) and micro-scale (within a collection site) diversity for disease reaction was found in the 116 accessions of H. spontaneum evaluated at the seedling stage. Additionally, genetic heterozygosity for resistance loci was common in H. spontaneum. The frequency of resistance in accessions from Jordan and Israel was high for Septoria speckled leaf blotch (77 and 98%, respectively), leaf rust (70 and 90%), net blotch (72 and 68%), and powdery mildew (58 and 70%); intermediate for spot blotch (53 and 46%); and low for stem rust (2 and 26%). The level of disease resistance in H. spontaneum was not strongly correlated with any of the weather variables (temperature, precipitation, and humidity) monitored near the collection sites. However, in general, resistance was more often found in germ plasm from mesic (e.g., Mediterranean coast) than in xeric (e.g., Negev Desert) areas. Two H. spontaneum accessions (Shechem 12-32 and Damon 11-11) were resistant to all six pathogens and may be useful parents in programs breeding barley for multiple disease resistance. The high level of diversity and heterozygosity for disease reaction found in this study indicates that H. spontaneum is an extraordinarily rich and largely untapped source of unique disease resistance alleles for cultivated barley improvement.
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Laidig, F., T. Feike, B. Klocke, J. Macholdt, T. Miedaner, D. Rentel y H. P. Piepho. "Long-term breeding progress of yield, yield-related, and disease resistance traits in five cereal crops of German variety trials". Theoretical and Applied Genetics 134, n.º 12 (15 de octubre de 2021): 3805–27. http://dx.doi.org/10.1007/s00122-021-03929-5.
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Abstract Key message Considerable breeding progress in cereal and disease resistances, but not in stem stability was found. Ageing effects decreased yield and increased disease susceptibility indicating that new varieties are constantly needed. Abstract Plant breeding and improved crop management generated considerable progress in cereal performance over the last decades. Climate change, as well as the political and social demand for more environmentally friendly production, require ongoing breeding progress. This study quantified long-term trends for breeding progress and ageing effects of yield, yield-related traits, and disease resistance traits from German variety trials for five cereal crops with a broad spectrum of genotypes. The varieties were grown over a wide range of environmental conditions during 1988–2019 under two intensity levels, without (I1) and with (I2) fungicides and growth regulators. Breeding progress regarding yield increase was the highest in winter barley followed by winter rye hybrid and the lowest in winter rye population varieties. Yield gaps between I2 and I1 widened for barleys, while they shrank for the other crops. A notable decrease in stem stability became apparent in I1 in most crops, while for diseases generally a decrasing susceptibility was found, especially for mildew, brown rust, scald, and dwarf leaf rust. The reduction in disease susceptibility in I2 (treated) was considerably higher than in I1. Our results revealed that yield performance and disease resistance of varieties were subject to considerable ageing effects, reducing yield and increasing disease susceptibility. Nevertheless, we quantified notable achievements in breeding progress for most disease resistances. This study indicated an urgent and continues need for new improved varieties, not only to combat ageing effects and generate higher yield potential, but also to offset future reduction in plant protection intensity.
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Zhou, Hao y Brian J. Steffenson. "Association Mapping of Septoria Speckled Leaf Blotch Resistance in U.S. Barley Breeding Germplasm". Phytopathology® 103, n.º 6 (junio de 2013): 600–609. http://dx.doi.org/10.1094/phyto-10-12-0271-r.
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Septoria speckled leaf blotch (SSLB) is a sporadic but important disease of barley (Hordeum vulgare) in the Upper Midwest region of the United States and Prairie Provinces of Canada that is caused primarily by Septoria passerinii. Most of the widely grown cultivars in the region are susceptible to the disease. To identify and map SSLB resistance loci in U.S. barley breeding germplasm, we employed an association mapping approach using 3,840 breeding lines and cultivars and nearly 3,000 single-nucleotide polymorphism markers previously mapped to the seven barley chromosomes. SSLB infection responses (IRs) were assayed on seedling plants in the greenhouse using a 0-to-5 scale. From the analysis of four yearly panels consisting of 960 lines each, four quantitative trait loci (QTL) for SSLB resistance were identified: one on chromosome 1H (Rsp-qtl-H_12_31144), one on chromosome 3H (Rsp-qtl-3H_12_31488), and two on chromosome 6H (Rsp-qtl-6H_11_21032 and Rsp-qtl-6H_11_10064). Individual resistance QTL reduced the mean IR from 9 to 38% compared with lines lacking any resistance alleles. However, the combination of all four resistance QTL together reduced the mean IR by 83%. The markers found associated with these QTL will be valuable for programs utilizing marker-assisted selection for SSLB resistance.
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Xi, K., X. M. Chen, F. Capettini, E. Falconi, R. C. Yang, J. H. Helm, M. D. Holtz et al. "Multivariate analysis of stripe rust assessment and reactions of barley in multi-location nurseries". Canadian Journal of Plant Science 93, n.º 2 (marzo de 2013): 209–19. http://dx.doi.org/10.4141/cjps2012-051.
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Xi, K., Chen, X. M., Capettini, F., Falconi, E., Yang, R. C., Helm, J. H., Holtz, M. D., Juskiw, P., Kumar, K., Nyachiro, J. and Turkington, T. K. 2013. Multivariate analysis of stripe rust assessment and reactions of barley in multi-location nurseries. Can. J. Plant Sci. 93: 209–219. A total of 1357 entries, mainly consisting of hulled two-row, hulled six-row and hulless barley, were evaluated in stripe rust nurseries at Toluca, Mexico during 2007, Quito, Ecuador during 2007 and 2008, and Pullman and Mt. Vernon, USA [Pacific Northwest (PNW)] during 2007–2009. Disease screening data for barley stripe rust resistance at multiple locations and seasons were analyzed using factor analysis (FA), principal component analysis (PCA) and analysis of variance (ANOVA). Factor analysis led to the removal of a number of disease assessment variables that had inadequate disease levels or an unsuitable rating scale. The PCA scores revealed that the two-row types of barley were generally more resistant than the six-row and hulless types. ANOVA indicated that the effect of seasonal influence on screening was small, while stripe rust susceptible and resistant barley types were differentiated significantly on mean values averaged on infection type (IT) and percentage diseased leaf area (disease severity, DS) during the 3-yr tests in multiple screening nurseries. The significant correlations in disease assessments between IT and DS suggest that either assessment can be used to replace the other without a significant loss of information regarding barley stripe rust reactions. The first principal component is a useful criterion for assessing stripe rust reactions in barley lines.
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Mykhailenko, S. y T. Shevchenko. "Effect of modern fungicides on severity of diseases of spring barley". Interdepartmental Thematic Scientific Collection of Plant Protection and Quarantine, n.º 65 (20 de diciembre de 2019): 124–32. http://dx.doi.org/10.36495/1606-9773.2019.65.124-132.
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Goal. To carry out monitoring of spring barley diseases and determine the technical efficiency of modern fungicides during the vegetation period.
Methods. The observations of disease severity were performed according to conventional methods. The technical efficiency of fungicides was studied in the Kyiv region, Belotserkovsky district, EB Alexandria in 2017—2018 under the conditions of natural infection on the cv. Commander. The size of the plots — 10 m2 in 4 replicates, the placement of plots — randomized. Agrotechnics are common for the growing area. Before the first application, an observation was carried out to establish the presence of diseases and their severity. In 15 days after the treatment with fungicides, records were taken to determine the development of the disease. Two treatments were performed with fungicides: the first at the flag leaf stage (39 stage on BBCH scale), the second — at booting stage (49 stage on BBCH scale). The following fungicides were tested: Aviator Xpro 225 EC, 0.8 l/ha, Acanto Plus 28 SC, 0.75 l/ha, Amistar Extra 280 SC, 0.75 l/ha, Abacus ES, 1.75 l/ ha, Bontima 250 EC, 2.0 l/ha.
Results. During the period of investigation, the following leaf diseases were the most common:net blotch (Pyrenophora teres Drechsler), brown spot (Bipolaris sorokiniana Shoemaker) and powdery mildew (збудник Blumeria graminis (DC.) Speer). The efficiency of fungicides against leaf diseases of spring barley was established. It was: against net blotch — 75.7—87.0%, brown spot — 70.0—80.0%, powdery mildew — 78.0—100%. The fungicide application made it possible to save a considerable part of the yield. The preserved yield at application of fungicides reached 0.18—0.27 t/ha. In the variants with the fungicides, the weight of 1000 grains increased by 3.3—4.4 g. A significant difference was observed between the variants and control over the parameters of the mass of 1000 grains.
Conclusions. In the 2017 and 2018 growing seasons in the Kyiv region, the complex of spring barley leaf diseases included: net blotch (Pyrenophora teres Drechsler), brown spot (Bipolaris sorokiniana Shoemaker) and powdery mildew (збудник Blumeria graminis (DC.) Speer). It is noted that for the protection of spring barley leaves it is advisable to apply one of the fungicides: Aviator Xpro 225 EC, 0.8 l/ha, Acanto Plus 28 SC, 0.75 l/ha, Amistar Extra 280 SC, 0.75 l/ ha, Abacus ES, 1.75 l/ha, Bontima 250 EC, 2.0 l/ha. The use of fungicides made it possible to protect the top two leaves from infection during grain filling, whach had a positive effect on the formation of structural elements, plant productivity and on quantitative and qualitative parameters of the yield.
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Vega, Jorge, Sandra M. M. Scagliusi y Eugênio C. Ulian. "Sugarcane Yellow Leaf Disease in Brazil: Evidence of Association with a Luteovirus". Plant Disease 81, n.º 1 (enero de 1997): 21–26. http://dx.doi.org/10.1094/pdis.1997.81.1.21.
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Evidence of the viral etiology of sugarcane yellow leaf disease (SCYLD), occurring in southeast Brazil, was obtained by light and electron microscopy combined with serology. Light microscopy using epifluorescence illumination showed an abnormal yellow-green fluorescing material in the phloem of SCYLD-affected plants that was rarely observed in control plants. Immunolocalization in tissue-printed (or -blotted) nitrocellulose membranes, using barley yellow dwarf virus (BYDV) serotype PAV antiserum, showed a weak but clearly positive reaction in the phloem. Isometric viruslike particles of 24 to 26 nm in diameter were found by electron microscopy both in situ and in partially purified preparations. Examination of thin sections showed that phloem companion cells contained viruslike particles and presented cytological changes apparently related to the development of virus infection. Partially purified preparations produced UV absorption spectra typical of a nucleoprotein, with high absorbance at 260 nm, as expected for isometric virus particles. Virus particles were observed in extracts and partially purified preparations using immunosorbent electron microscopy with BYDV-PAV antiserum. Plate-trapped antigen enzyme-linked immunosorbent assays with the same antiserum indicate a weak serological relationship between BYDV-PAV and SCYLD-associated virus.
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Wolfe, R. I., D. G. Faris, J. G. N. Davidson y P. J. Clarke. "AC Stacey barley". Canadian Journal of Plant Science 75, n.º 2 (1 de abril de 1995): 461–63. http://dx.doi.org/10.4141/cjps95-078.
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AC Stacey is an early maturing, six-row feed barley (Hordeum vulgare L.) with excellent barley leaf scald resistance. It was developed at the Northern Agriculture Research Centre, Beaverlodge, Alberta from the cross Otal/Melvin. It is moderately strong strawed, and adapted to barley leaf scald prone areas in Alberta, and the Peace River region of British Columbia. Key words:Hordeum vulgare, barley, early maturity, cultivar description, Rhynchosporium secalis, scald
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Dracatos, Peter M., Michael Ayliffe, Mehar S. Khatkar, Tom Fetch, Davinder Singh y Robert F. Park. "Inheritance of Prehaustorial Resistance to Puccinia graminis f. sp. avenae in Barley (Hordeum vulgare L.)". Molecular Plant-Microbe Interactions® 27, n.º 11 (noviembre de 2014): 1253–62. http://dx.doi.org/10.1094/mpmi-05-14-0140-r.
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Rust pathogens within the genus Puccinia cause some of the most economically significant diseases of crops. Different formae speciales of P. graminis have co-evolved to mainly infect specific grass hosts; however, some genotypes of other closely related cereals can also be infected. This study investigated the inheritance of resistance to three diverse pathotypes of the oat stem rust pathogen (P. graminis f. sp. avenae) in the ‘Yerong’ ✕ ‘Franklin’ (Y/F) barley doubled haploid (DH) population, a host with which it is not normally associated. Both parents, ‘Yerong’ and ‘Franklin’, were immune to all P. graminis f. sp. avenae pathotypes; however. there was transgressive segregation within the Y/F population, in which infection types (IT) ranged from complete immunity to mesothetic susceptibility, suggesting the presence of heritable resistance. Both QTL and marker-trait association (MTA) analysis was performed on the Y/F population to map resistance loci in response to P. graminis f. sp. avenae. QTL on chromosome 1H (‘Yerong’ Rpga1 and Rpga2) were identified using all forms of analysis, while QTL detected on 5H (‘Franklin’ Rpga3 and Rpga4) and 7H (Rpga5) were only detected using MTA or composite interval mapping–single marker regression analysis respectively. Rpga1 to Rpga5 were effective in response to all P. graminis f. sp. avenae pathotypes used in this study, suggesting resistance is not pathotype specific. Rpga1 co-located to previously mapped QTL in the Y/F population for adult plant resistance to the barley leaf scald pathogen (Rhynchosporium secalis) on chromosome 1H. Histological evidence suggests that the resistance observed within parental and immune DH lines in the population was prehaustorial and caused by callose deposition within the walls of the mesophyll cells, preventing hyphal penetration.
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Falk, D. E., G. Meatherall y B. G. Rossnagel. "Codac barley". Canadian Journal of Plant Science 76, n.º 4 (1 de octubre de 1996): 799–800. http://dx.doi.org/10.4141/cjps96-134.
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Codac is a six-rowed spring feed barley (Hordeum vulgare L.) bred at the Crop Development Centre, University of Saskatchewan and registered by the Crop Science Department, University of Guelph for Eastern Canada. It was produced from a cross of Diamond/Duke and has shown adaptation to Eastern Canada. It has been high yielding, early maturing and has medium height straw. It has good resistance to scald, leaf rust, stem rust and the smuts, but is susceptible to powdery mildew. Key words: Six-rowed barley (spring), Hordeum vulgare L., feed barley, high yield, early maturity, smut resistance, scald resistance, cultivar description
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Jiao, Yujie y Ling Yuan. "Positive effects of increasing crop diversity in land use on soil microbial biomass, enzyme activity and bacterial community composition". Soil Research 57, n.º 7 (2019): 779. http://dx.doi.org/10.1071/sr18240.
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A rotation of summer tobacco–winter barley–next summer maize (T-B-M) has been suggested by Chinese government programs as an alternative land use practice to replace the conventional tobacco–fallow monoculture (T) and tobacco–barley succession (T-B) management systems. Crop yield in each crop system was recorded from 2010 to 2016 and routine and 454 pyrosequencing approaches were used to evaluate the effects of these cropping systems on organic matter, enzyme activity, and bacterial biomass and community composition within the same soil type. Tobacco leaf yields, barley grains, organic matter, microbial biomass, and enzyme activity (urease, neutral phosphatase, invertase and dehydrogenase) in the soil increased with crop species (but differences were not significant for dehydrogenase activity between T and T-B, and for neutral phosphatase activity between T-B and T-B-M). Indices of richness and diversity of soil bacterial communities also increased as the number of 16S rRNA gene sequences and bacterial phylotypes in the soil increased. The presence of many different bacteria in a soil system may prevent excess reproduction of any single pathogenic bacterium and subsequently reduce the risk of large-scale disease spread. All cropping soils were dominated by Proteobacteria, Acidobacteria, Actinobactria, Bacteroidetes, and unclassified bacteria. Of the 20 predominant bacteria, 13 were commonly found in all soils studied, whereas only four to five were unique in each of the soils examined. This suggests that the presence of those bacteria was more influenced by soil properties than cropping systems in a period of land use.
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COUTURE, LUC y DANIEL ISFAN. "EFFET DE LA FERTILISATION AZOTEE SUR LE DEVELOPPEMENT DE LA RHYNCHOSPORIOSE DE L’ORGE". Canadian Journal of Plant Science 66, n.º 3 (1 de julio de 1986): 795–99. http://dx.doi.org/10.4141/cjps86-098.
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The effect of nitrogen fertilizers applied as urea or ammonium nitrate at doses of 0, 40, 80, 120, and 160 kg ha−1 on scald in spring barley (Hordeum vulgare) grown on two different soils was examined during 2 yr. A strong significant positive correlation was found between nitrogen dose and severity of scald during the 2 yr. Nitrogen influenced disease severity the same way in both soils although the absolute level of disease was higher in plots set up in sandy loam than in clay soil. Disease severity was approximately the same in barley fertilized with urea or ammonium nitrate.Key words: Nitrogen fertilizer, nitrogen form, barley, Hordeum vulgare, scald, Rhynchosporium secalis
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Gabardo, Gislaine, Clandio Medeiros da Silva, Henrique Luis da Silva, Iohann Metzger Iauchrowitz, Flávio Corrêa Carvalho y Rui Pereira Leite Junior. "Selection of plum genotypes for resistance to leaf scald". Summa Phytopathologica 46, n.º 4 (diciembre de 2020): 305–7. http://dx.doi.org/10.1590/0100-5405/238868.
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ABSTRACT Plum (Prunus salicina Lindl.) cultivation is seriously compromised in Brazil due to the occurrence of leaf scald, a disease caused by the bacterium Xylella fastidiosa subsp. multiplex. The objective of this study was to evaluate plum genotypes agronomically promising for resistance to leaf scald, under natural conditions of occurrence of the disease. Ten out of 50 plum genotypes belonging to the germplasm bank of “Instituto Agronômico do Paraná (IAPAR)” were selected. Five evaluations of leaf scald severity were carried out from January to February (2017 and 2018). Polymerase chain reaction (PCR) was also performed for samples of these genotypes to determine the presence of the bacterium X. fastidiosa subsp. multiplex. The genotypes differed in relation to their susceptibility to leaf scald. PR-1095 was the most resistant genotype and did not show any leaf symptom of the disease. In contrast, genotypes PR-1126 and PR-1137 had the greatest susceptibility to the disease, showing severe scald symptoms. However, PCR revealed the presence of the bacterium even in the most resistant genotypes, indicating, for example, that PR-1095, which had no symptoms of the disease, is probably tolerant to leaf scald.
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Korhoň, Radim, Petr Svačina, Dana Komoňová y Monika Škopová. "Spring barley variety Laudis 550". Czech Journal of Genetics and Plant Breeding 55, No. 3 (17 de junio de 2019): 128–30. http://dx.doi.org/10.17221/41/2018-cjgpb.
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Laudis 550 is a mid-late malting spring barley variety, medium resistant to lodging and medium resistant to stem brackling. It is resistant to powdery mildew, medium resistant to brown rust, leaf blotch complex and scald. The variety reached 7.2 points of the malting quality index (to the registration date) and it is recommended by the Research Institute of Brewing and Malting, Plc for production of beer with the protected geographical indication České pivo (Czech beer).
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Yitbarek, S., L. Berhane, A. Fikadu, J. A. G. van Leur, S. Grando y S. Ceccarelli. "Variation in Ethiopian barley landrace populations for resistance to barley leaf scald and netblotch". Plant Breeding 117, n.º 5 (noviembre de 1998): 419–23. http://dx.doi.org/10.1111/j.1439-0523.1998.tb01966.x.
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Abbott, D. C., J. J. Burdon, A. H. D. Brown, B. J. Read y D. Bittisnich. "The incidence of barley scald in cultivar mixtures". Australian Journal of Agricultural Research 51, n.º 3 (2000): 355. http://dx.doi.org/10.1071/ar99087.
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A field trial incorporating resistant and susceptible plants in mixed plots, where the proportion of resistant plants was 0%, 50%, or 100%, indicated that cultivar mixtures were not particularly effective for the control of barley scald disease. Combining 2 scald resistance genes into a single line was more effective in controlling disease than deploying the same genes singly in different lines in a mixture. The lack of benefit from mixtures in this experiment differed from the findings of 2 previous studies investigating scald resistance in mixtures. Although the study included only one growing season and one location, the findings suggest that the use of mixtures for controlling this disease may carry some risk and that breeding for a resistance pyramid is likely to be more widely effective.
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Brown, JS. "Definition of infection period for field infection of scald in Victoria". Australian Journal of Agricultural Research 42, n.º 5 (1991): 811. http://dx.doi.org/10.1071/ar9910811.
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Conditions suitable for infection of barley with Rhynchosporium secalis were determined by exposing seedlings to inoculum from scald-infected barley plants growing in the field. Maximum infection occurred when the duration of leaf surface wetness was c. 12 h and the average temperature during those periods was c. 6�C. On this basis potential infection periods were defined as periods of leaf surface wetness of >12 h duration with an average temperature of >6�C during the period. Meterological records indicated that during the 1983-89 growing seasons there was an average of 91 periods of leaf surface wetness per year at Walpeup and 104 at Horsham and that c. 20% were potential infection periods. The modal duration of leaf surface wetness category was >9-12 h at Horsham and >0-3 h at Walpeup and the modal average temperature category during periods of leaf surface wetness was >6-9�C at both locations. None of the six most commonly occurring combinations of duration and temperature during periods of leaf surface wetness met the criteria for potential infection periods defined above.
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Daugrois, Jean Heinrich, Rosiane Boisne-Noc y Philippe Rott. "Leaf Surface Colonization of Sugarcane by Xanthomonas albilineans and Subsequent Disease Progress Vary According to the Host Cultivar". Plant Disease 98, n.º 2 (febrero de 2014): 191–96. http://dx.doi.org/10.1094/pdis-02-13-0195-re.
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Spread of leaf scald in modern sugarcane cultivars in Guadeloupe occurs through aerial dissemination of Xanthomonas albilineans. However, the importance of host genotype on the foliar spread of leaf scald has never been investigated. To explore this, we followed two trials used to screen sugarcane cultivars for resistance to leaf scald under natural inoculum pressure. Leaf scald epidemic characteristics were studied by measuring epiphytic populations of X. albilineans, leaf symptom incidence and severity, and the number of infected stalks. In both trials, epiphytic X. albilineans populations and incidence of foliar symptoms varied between sugarcane cultivars (P < 0.001 in each trial for both traits) and differences in stalk infection between cultivars was also observed (P < 0.002 and P < 0.07 for trials A and B, respectively). Part of the cultivar resistance that minimizes epiphytic bacterial populations is correlated to resistance to internal leaf tissue infection as expressed by leaf symptoms. No correlation was found between epiphytic X. albilineans populations of cultivar and the incidence of stalk infection. However, foliar symptom incidence was inconsistently correlated with stalk infection. Resistance of sugarcane to leaf scald appears to involve several traits, including limiting size of epiphytic X. albilineans populations and limiting the capacity of the pathogen to produce leaf necrotic symptoms by invading the leaf vascular system or to move from the leaf into the stalk.
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Khan, TN y MF D'Antuono. "Relationship between scald (Rhynchosporium secalis) and losses in grain yield of barley in Western Australia". Australian Journal of Agricultural Research 36, n.º 5 (1985): 655. http://dx.doi.org/10.1071/ar9850655.
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The three commonly used techniques, viz. critical point model, area under the curve and multiple linear regression, were applied to study the relationship between scald infection and grain yield in field experiments conducted during 1979-1983 in Western Australia. In the preliminary analysis leaf three from the top and the mean of the top three leaves were found to be best correlated with yield. The three models did not dilfer greatly, presumably owing to the high correlations between scald at the milky ripe stage and at the earlier growth stages. The critical point model was chosen because of its simplicity. Percentage yield loss in combined data from all experiments showed a significant correlation (P < 0.001) with scald at the milky ripe stage and defined percentage yield loss in cultivars Clipper and Stirling to be about one-third of the mean scald damage on leaves 1 (flag), 2 and 3 at g.s. 75. Due to the range of trials in this analysis, it was suggested that this relationship may be applied to estimate yield loss from survey data in other parts of southern Australia, where scald is endemic.
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Khan, TN. "Effects of fungicide treatments on scald (Rhynchosporium secalis (Oud.) J. Davis) infection and yield of barley in Western Australia." Australian Journal of Experimental Agriculture 26, n.º 2 (1986): 231. http://dx.doi.org/10.1071/ea9860231.
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Application of fungicides (benomyl and triadimefon) to early sown barley (cv. Clipper) in 1979 and 1980 reduced the incidence of scald and greatly increased grain yield. Fungicide applied to the young crop 4-6 weeks after sowing was ineffective but applications at 10 and 12 weeks indicated that economic returns from the use of fungicides could be obtained. In subsequent experiments on cv. Stirling, an application at the 6-7 leaf stage gave the most consistent grain yield increase, ranging from 15 to 48% (225-937 kg/ha). Triadimefon was found to be more effective in reducing scald than was benomyl but gave no greater yield increases. Controlling scald by multiple application of fungicide increased harvest dry weight, number of heads/m2, number of grains/head and 100-seed weight, and prevented lodging in at least two trials. A single application, though it may be economic, offers only partial control of scald, and resistant cultivars are therefore necessary to achieve full yield potential in scald-prone areas.
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Genger, R. K., K. J. Williams, H. Raman, B. J. Read, H. Wallwork, J. J. Burdon y A. H. D. Brown. "Leaf scald resistance genes in Hordeum vulgare and Hordeum vulgare ssp. spontaneum: parallels between cultivated and wild barley". Australian Journal of Agricultural Research 54, n.º 12 (2003): 1335. http://dx.doi.org/10.1071/ar02230.
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The prerequisite for breeding barley varieties with durable scald resistance is a diversity of genes each with molecular markers for their manipulation in crosses. Here we compare the outcomes of genetic analysis of scald resistance in 5 doubled haploid mapping populations of cultivated barley with 9 third-backcross families that derive from a set of diverse wild barley populations. In all cases, resistance was assessed as seedling infection type responses, but the Sloop/Halcyon population was also tested for adult plant resistance in field trials at two sites. In the latter case, the major quantitative trait locus for field resistance was coincident with that for seedling response on chromosome 3H. Most of the other cultivated barley sources of resistance in this study (1 cultivar and 3 breeders populations synthesised for resistance) also resolved to markers in the region of this 3H locus. In contrast, the genetic basis of resistance in wild barley populations resolved to at least 5 chromosome locations (1HS, 3H, 6HS, 7HL, and 7HS). Useful markers were of several kinds including proteins, isozymes, PCR based on RFLPs, AFLP, and SSR loci. Thus, wild barley increases the range of options for pyramid breeding and provides linked molecular markers that will be useful in manipulating those genes, or in the analysis of resistance in new sources.
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Champoiseau, P., P. Rott y J. H. Daugrois. "Epiphytic Populations of Xanthomonas albilineans and Subsequent Sugarcane Stalk Infection Are Linked to Rainfall in Guadeloupe". Plant Disease 93, n.º 4 (abril de 2009): 339–46. http://dx.doi.org/10.1094/pdis-93-4-0339.
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Three separate field trials were established in Guadeloupe under different agronomic and rainfall conditions to study phyllosphere contamination and infection of sugarcane plants by Xanthomonas albilineans, the causal agent of sugarcane leaf scald. Disease-free and leaf scald susceptible cv. B69566 was planted and monitored during three 1-year crop cycles. Presence of leaf scald contaminated sugarcane fields in the proximity of the disease-free trials appeared critical in early contamination of the sugarcane phyllosphere. Later on, particular meteorological events, such as tropical storms, were also important in aerial spread of the pathogen. A positive correlation was found between epiphytic populations of X. albilineans and severity of leaf necrotic symptoms, but occurrence of leaf symptoms was not always related to subsequent stalk infection. However, when the data of the three crop seasons were considered together, a high correlation was found between rainfall and maximum epiphytic populations of X. albilineans, and between rainfall and subsequent stalk infections. Consequently, rainfall is a key factor to be considered in evaluation of risks of leaf scald epidemics, and protocols for propagation of healthy sugarcane material and screening methods for leaf scald resistance may have to be revised in humid tropical locations.
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Zhang, Ming-Yang, Ding-Kai Hong, Yao-Hui Chen, San-Ji Gao, Hua-Ying Fu, Hua-Kun Zheng, Yong Fang y Jin-Da Wang. "Synergistic Effects of Organosilicon and Cu(OH)2 in Controlling Sugarcane Leaf Scald Disease". International Journal of Molecular Sciences 23, n.º 21 (4 de noviembre de 2022): 13532. http://dx.doi.org/10.3390/ijms232113532.
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Sugarcane leaf scald is a systemic disease caused by Xanthomonas albilineans that limits sugarcane yield and quality. Previous research has shown that exogenous application of copper hydroxide to plants is effective in controlling this disease. However, long-term bactericide use causes serious “3R” problems: resistance, resurgence, and residue. It is therefore urgent to discover new methods for the improvement of bactericide efficiency and efficacy. In the present study, disease index values for leaf scald were measured in sugarcane seedlings over time to determine the effects of different concentrations of copper hydroxide, types of silicon additive, and treatment timing after inoculation with X. albilineans on controlling sugarcane leaf scald disease. Our results show copper hydroxide mixed with organosilicon additive could improve the bactericide efficiency and efficacy and reduce the growth of pathogenic bacteria, even at a reduced concentration in both laboratory and field conditions. This study provides an important practical model for controlling sugarcane leaf scald disease by reducing the concentration of bactericide and increasing its efficacy in sugarcane fields.
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Karjalainen, R. y K. Jokinen. "Influence of Barley Scald Disease on Yield and Competition in Barley-Oat Mixtures". Journal of Agronomy and Crop Science 171, n.º 5 (diciembre de 1993): 314–20. http://dx.doi.org/10.1111/j.1439-037x.1993.tb00146.x.
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Singh, A. K., B. G. Rossnagel, G. J. Scoles y R. A. Pickering. "Inheritance of scald resistance from barley lines 4176/10/n/3/2/6 and 145L2". Canadian Journal of Plant Science 83, n.º 2 (1 de abril de 2003): 417–22. http://dx.doi.org/10.4141/p02-063.
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Scald incited by Rhynchosporium secalis (Oud.) J.J. Davis is an important fungal foliar disease of barley (Hordeum vulgare L.) that can cause significant yield and quality losses. While application of fungicides and/or cultural practices are possible control methods, the use of genetic resistance is a very desirable control strategy. Two New Zealand barley lines, 4176/10/n/3/2/6 and 145L2, derived from interspecific crosses, were evaluated in scald nurseries at Lacombe and Edmonton, AB, in 1998 and exhibited a high level of resistance. The objectives of this study were to further evaluate the level of resistance in these lines under western Canadian conditions and to study the inheritance of that resistance. Lines 4176/10/n/3/2/6 and 145L2 were each crossed with the scald susceptible cultivars CDC McGwire and RFLP Harrington. A scald screening nursery at Lacombe, AB, was utilized for disease testing in 1999 and nurseries at Lacombe and Edmonton, AB, were used in 2000. The F1 and F2 generations of all resistant/susceptible crosses were evaluated in 1999. One hundred F4:5 recombinant inbred lines from each cross were evaluated in replicated trials in 2000. Lines 4176/10/n/3/2/6 and 145L2 were resistant in all trials and resistant/susceptible populations segregated for single gene control of resistance in the F2 and F4:5 generations. Chi square analysis indicated that they possess a single dominant gene for resistance. These two lines should provide simply inherited sources of scald resistance for western Canada. Key words: Scald, barley, inheritance, resistance, Rhynchosporium secalis
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Singh, A. K., G. J. Scoles, R. A. Pickering y B. G. Rossnagel. "Allelic studies of new sources of scald (Rhynchosporium secalis Davis) resistance in barley". Canadian Journal of Plant Science 83, n.º 4 (1 de octubre de 2003): 709–13. http://dx.doi.org/10.4141/p02-103.
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The use of genetic resistance is a desirable disease management strategy for controlling scald (Rhynchosporium secalis Davis) in barley (Hordeum vulgare L.); thus, it is essential to screen for new sources of resistance. The objectives of this study were to test the novelty of scald resistance in two barley lines from New Zealand, 145L2 and 4176/10/n/3/2/6, relative to a number of resistance sources available to western Canadian breeding programs, and to determine the source of this resistance. 145L2 and 4176/10/n/3/2/6 were resistant in New Zealand and in scald screening nurseries in Alberta, Canada, in 1998. 145L2 was crossed with 4176/10/n/3/2/6 and with four local resistant lines to determine allelic relationships between 145L2 resistance, 4176/10/n/3/2/6 resistance and the resistance(s) in the local lines. To determine the source of the resistance, all H. vulgare L. lines in the pedigree of the New Zealand lines were evaluated in the same nurseries. The resistance gene in 145L2 was not allelic to that in 4176/10/n/3/2/6 or the other barley lines tested. All lines in the pedigree of the two New Zealand lines were susceptible, suggesting that their resistance is derived from unknown parents in their pedigrees. These New Zealand lines provide new sources of scald resistance that can be incorporated into western Canadian breeding lines. Key words: Barley, scald, resistance
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Singh, A. K., B. G. Rossnagel, G. J. Scoles y R. A. Pickering. "Identification of a quantitatively inherited source of Hordeum bulbosum derived scald resistance from barley line 926K2/11/1/5/1". Canadian Journal of Plant Science 84, n.º 3 (1 de julio de 2004): 935–38. http://dx.doi.org/10.4141/p02-181.
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Scald resistance breeding requires identification and incorporation of novel resistance sources into local breeding populations. A New Zealand barley Hordeum vulgare L.) line (926K2/11/1/5/1) was evaluated in scald [Rhynchosporium secalis (Oud.) J.J. Davis] nurseries at Lacombe and Edmonton, Alberta, Canada, as a potential source of scald resistance derived from H. bulbosum. Primary objectives were to evaluate the level of resistance in 926K2/11/1/5/1 under Canadian conditions and determine its mode of inheritance. In western Canadian nurseries, 926K2/11/1/5/1 exhibited moderate resistance. 926K2/11/1/5/1 was crossed with the scald-susceptible cultivar CDC McGwire and resulting progeny (F2 and F4:5 recombinant inbred lines) were tested for normality of disease reaction distribution, and were used to estimate the number of effective factors controlling the resistance. F1 plants expressed an intermediate scald reaction compared with the parents. F2 and F4:5 data were normally distributed. Estimation of the number of effective factors using the Castle-Wright formula indicated that resistance from 926K2/11/1/5/1 is quantitatively inherited, but controlled by relatively few genes. The moderate scald resistance in 926K2/11/1/5/1 is an additional resistance source plant breeders can utilize. Key words: Barley, scald, quantitative resistance, Hordeum bulbosum
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., H. Kavak y Z. Katircioglu . "Effects of Different Sowing Frequencies on Barley Leaf Scald and Some Yield Components". Pakistan Journal of Biological Sciences 8, n.º 4 (15 de marzo de 2005): 662–64. http://dx.doi.org/10.3923/pjbs.2005.662.664.
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Xue, G. y R. Hall. "Effects of surface wetness duration, temperature, and inoculum concentration on infection of winter barley by Rhynchosporium secalis". Phytoprotection 73, n.º 2 (12 de abril de 2005): 61–68. http://dx.doi.org/10.7202/706020ar.
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The effects of surface wetness duration, temperature, and inoculum concentration on development of scald in winter barley (Hordeum vulgare) inoculated with race SOI of Rhynchosporium secalisfrom southern Ontario, Canada were examined. On barley line 'GW8614' sprayed with a spore suspension (2 x 105 conidia ml-1), wet periods of 2-48 h and constant temperatures of 10-25°C during the wet and dry periods, 10-25°C during the wet period and 20°C during the dry period, or 20°C during the wet period and 10-30°C during the dry period allowed scald to develop 8.3-11.5 d after inoculation. The disease developed most rapidly and most severely when the wet period after inoculation was 48 h and the temperature of the wet period and subsequent dry period was 20°C. Scald did not develop within 14 d following temperatures of 30°C during the wet period or of 5°C during the wet or dry periods. At inoculum densities of 102-106 conidia ml-1, the disease severity index values (0-100 scale) increased from 53 to 100 in line 'GW8614' and from 0 to 90 in cultivar OAC Acton and the latent periods decreased from 13.3 to 7.8 d in line 'GW8614' and from more than 14 to 8.5 d in cv. OAC Acton. This information should facilitate screening of barley for resistance to scald.