scholarly journals Diversity and Distribution of Rice Blast (Pyricularia oryzae Cavara) Races in Vietnam

Plant Disease ◽  
2020 ◽  
Vol 104 (2) ◽  
pp. 381-387 ◽  
Author(s):  
Nguyen T. M. Nguyet ◽  
Hoang H. Long ◽  
Nguyen B. Ngoc ◽  
Nguyen T Nhai ◽  
Nguyen T. T. Thuy ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Rice Blast ◽  
Pyricularia Oryzae ◽  
Red River ◽  
Red River Delta ◽  
North Central ◽  
South Central ◽  
Central Vietnam ◽  
Differential Varieties ◽  
Reaction Patterns

A total of 239 isolates of blast (Pyricularia oryzae Cavara) collected from northern and central Vietnam showed a wide variation in pathogenicity based on the reaction patterns to 25 differential varieties (DVs) harboring 23 resistance genes and susceptible cultivar Lijiangxintuanheigu (LTH). The frequencies of isolates virulent toward DVs for Pish, Pik-m, Pi1, Pik-h, Pik, Pik-p, Pi7(t), Pi9(t), Piz-5, Pita-2, and Pita were low, but they were high for DVs for Pib, Pit, Pia, Pii, Pi3, Pi5(t), Pik-s, Piz, Piz-t, Pi12(t), Pi19(t), and Pi20(t). Isolates were classified into three cluster groups Ia, Ib, and II based on reaction patterns to DVs and LTH. The frequencies of isolates virulent toward 11 DVs for Pik-m, Pi1, Pik-h, Pik, Pik-p, Pi7(t), Pi9(t), Piz, Piz-5, Pita-2, and Pita in cluster II and DV for Piz-t were higher and lower than those of Ia and Ib, respectively. The frequencies to DVs for Pii, Pi3, Pi5(t), and Piz-t were different between clusters Ia and Ib. Clusters Ia and Ib were distributed with similar frequencies in the northeast, north central, and south central coast regions, but the frequencies among three cluster groups in the Red River Delta and northwest regions were different. This means that the blast races in these two regions were different from the others. Overall, the blast isolates were categorized into 153 races. Among them, 26 were selected as a set of standard differential blast isolates for characterizing 23 resistance genes and developing a differential system in Vietnam.

scholarly journals Diversity and Distribution of Rice Blast (Pyricularia oryzae Cavara) Races in Bangladesh

Plant Disease ◽  
2016 ◽  
Vol 100 (10) ◽  
pp. 2025-2033 ◽  
Author(s):  
M. A. I. Khan ◽  
M. A. Ali ◽  
M. A. Monsur ◽  
A. Kawasaki-Tanaka ◽  
N. Hayashi ◽  
...  
Keyword(s):  
Cluster Analysis ◽  
Resistance Genes ◽  
Rice Blast ◽  
Blast Resistance ◽  
Pyricularia Oryzae ◽  
Blast Protection ◽  
Blast Resistance Gene ◽  
Group I ◽  
Differential Varieties ◽  
Reaction Patterns

The pathogenicity of 331 blast isolates (Pyricularia oryzae Cavara) collected from different regions and ecosystems for rice cultivation in Bangladesh was evaluated by compatibility on 23 differential varieties (DV), each harboring a single blast resistance gene, and susceptible ‘Lijiangxintuanheigu’ (LTH). A wide variation in virulence was found among the isolates, and 267 races were classified using a new designation system. Virulence of blast isolates against DV carrying the resistance genes Pia, Pib, Pit, Pik-s, Piz-t, Pi12(t), Pi19(t), and Pi20(t), as well as avirulence against those carrying Pish, Pi9, Pita-2, and Pita, was distributed widely in Bangladesh. Cluster analysis of the compatibility data on the DV initially classified the isolates into groups I and II. The virulence spectra of the two groups differed mainly according to the reactions of the DV to Pii, Pi3, Pi5(t), Pik-m, Pi1, Pik-h, Pik, Pik-p, and Pi7(t). Group I isolates were distributed mainly in rainfed lowlands, whereas group II isolates were found mainly in irrigated lowlands; however, there were no critical differences in geographic distribution of the blast isolates. In total, 26 isolates, which could be used to identify the 23 resistance genes of the DV on the basis of their reaction patterns, were selected as a set of standard differential blast isolates. To our knowledge, this is the first clear demonstration of the diversity and differentiation of blast races in Bangladesh. This information will be used to develop a durable blast protection system in that country.

scholarly journals Pathogenicities of Rice Blast (Pyricularia oryzae Cavara) Isolates From Kenya

Plant Disease ◽  
2019 ◽  
Vol 103 (12) ◽  
pp. 3181-3188 ◽  
Author(s):  
Yoshimichi Fukuta ◽  
Mary Jeanie Telebanco-Yanoria ◽  
Nagao Hayashi ◽  
Seiji Yanagihara ◽  
Catherine Wanjiku Machungo ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Rice Blast ◽  
Pyricularia Oryzae ◽  
The Other ◽  
Tana River ◽  
Geographical Regions ◽  
Differential Varieties ◽  
Reaction Patterns

A total of 99 isolates of rice blast (Pyricularia oryzae Cavara) were collected from 2010 to 2015 from four regions in Kenya: Kirinyaga County and Embu County, Kisumu County, Tana River County, and Mombasa County. The pathogenicities of these isolates were clarified based on the reaction patterns of Lijiangxintuanheigu and differential varieties (DVs) targeting 23 resistance genes. The frequency of virulent isolates was high for DVs for Pib, Pia, Pii, Pi3, Pi5(t), Pik-s, Pik-m, Pi1, Pik-h, Pik, Pik-p, Pi7(t), Pi19(t), and Pi20(t); low for DVs for Pish, Pi9(t), Piz-5, and Piz-t; and intermediate for the remaining DVs for Pit, Piz, Pita-2, Pita, and Pi12(t). These blast isolates were classified into three cluster groups: Ia, Ib, and II. The frequencies of virulent isolates to DVs for Pit, Pii, Pik-m, Pi1, Pik-h, Pik, Pik-p, Pi7(t), Piz, and Pi12(t) differed markedly between clusters I and II, and those of DVs for Pib, Pit, Pia, Pi3, Pita-2, Pita, and Pi20(t) differed between Ia and Ib. The frequencies of cluster groups in the four geographical regions were different. A total of 62 races were found, with 19 blast isolates categorized into one race (U63-i7-k177-z00-ta003), whereas the other races included only some isolates in each.

scholarly journals Diversity and Distribution of Rice Blast (Pyricularia oryzae Cavara) Races in Japan

Plant Disease ◽  
2016 ◽  
Vol 100 (4) ◽  
pp. 816-823 ◽  
Author(s):  
A. Kawasaki-Tanaka ◽  
N. Hayashi ◽  
S. Yanagihara ◽  
Y. Fukuta
Keyword(s):  
Cluster Analysis ◽  
Rice Blast ◽  
Oryza Sativa L ◽  
Pyricularia Oryzae ◽  
Central Japan ◽  
Original Population ◽  
Group I ◽  
Differential Varieties ◽  
Reaction Patterns ◽  
Northern Japan

In total, 310 rice blast (Pyricularia oryzae Cavara) isolates from Japan showed wide variation in virulence. Virulence on rice (Oryza sativa L.) differential varieties (DV) harboring resistance genes Pish, Pia, Pii, Pi3, Pi5(t), Pik-s, and Pi19(t) ranged from 82.9 to 100.0%. In contrast, virulence on DV possessing Pib, Pit, Pik-m, Pi1, Pik-h, Pik, Pik-p, Pi7(t), Pi9(t), Piz, Piz-5, Piz-t, Pita-2, Pita, Pi12(t), and Pi20(t) ranged from 0 to 21.6%. Cluster analysis using the reaction patterns of the DV classified isolates into three groups: I, virulent to Pik, Pik-h, Pik-p, Pik-m, Pi1, and Pi7(t); IIa, avirulent to the preceding 6 genes and virulent to Pia, Pii, Pi3, and Pi5(t); and IIb, avirulent to all 10 genes. Group I was limited to northern Japan and group IIb to central Japan, while group IIa was distributed throughout Japan. We estimate that group IIa represents the original population and that groups I and IIb arose from it through minor changes in pathogenicity. We classified these isolates into 123 races by a new designation system and conclude that the rice blast races in Japan are less diverse than previously thought.

Pathogenicity of Isolates of the Rice Blast Pathogen (Pyricularia oryzae) from Indonesia

Plant Disease ◽  
2020 ◽  
Author(s):  
Santoso Kadeawi ◽  
Suwarno Non ◽  
Anggiani Nasution ◽  
Aris Hairmansis ◽  
Mitsuhiro Obara ◽  
...  
Keyword(s):  
Differential System ◽  
Resistance Genes ◽  
Rice Blast ◽  
Pyricularia Oryzae ◽  
The Other ◽  
Blast Disease ◽  
Rice Cultivars ◽  
Rice Ecosystems ◽  
Susceptible Control ◽  
Differential Varieties

A total of 201 isolates of Pyricularia oryzae (the causal agent of rice blast) were collected from three rice ecosystems (upland, lowland, and swampy) in five regions of Indonesia (West Java, Lampung, South Sumatra, Kalimantan, and Bali). Their pathogenicities were characterized based on the patterns of reaction of 25 differential varieties (DVs) and the susceptible control Lijiangxintuanheigu (LTH), which was susceptible to all blast isolates. A high proportion of isolates (>80.0%) were virulent to DVs for resistance genes Pib, Pit, Pia, Pik-s, and Pi12(t), and a low proportion of isolates (<12.9%) were virulent to DVs for Pik-m, Pi1, Pik-h, Pik, Pik-p, and Pi7(t). Virulence to the other DVs for Pish, Pii, Pi3, Pi5(t), Pi9(t), Piz, Piz-5, Piz-t, Pita-2 (two lines), Pita (two lines), Pi19(t), and Pi20(t) showed intermediate frequencies from 20.0% to 80.0%. These isolates were classified into three cluster groups Ia, Ib, and II, and the frequencies of cluster groups varied among the three ecosystems and the five regions. The frequencies of cluster groups varied among the different ecosystems and regions, and races varied according to the ecosystems. A total of 27 standard differential blast isolates (SDBLs) were selected from the 201 isolates collected. The set of 25 DVs and these 27 SDBIs will be used as a new differential system for analysis of the pathogenicity of blast isolates and analysis of resistance genes in rice cultivars, which will contribute to building up a durable protection system against blast disease in Indonesia.

scholarly journals Distribution of Elite Students in Vietnam Revealed by National Olympiads

2020 ◽  
Author(s):  
Duy Nghia Pham
Keyword(s):  
Social Science ◽  
Ethnic Minority ◽  
Minority Students ◽  
Natural Science ◽  
Red River ◽  
Male Students ◽  
Red River Delta ◽  
North Central ◽  
The North ◽  
Science Test

Vietnamese National Olympiads 2010-2020 has awarded elite students more than 24,000 prizes. Provinces in the Red River Delta and the North Central Coast with their high schools for the gifted led the country in the number of elite students and the proportion of highest achievers. In comparison with social science test subjects, natural science subjects were more characterized by younger students and male students and less represented by ethnic minority students.

scholarly journals Performance of SEACLID/CORDEX-SEA multi-model experiments in simulating temperature and rainfall in Vietnam

2019 ◽  
Vol 41 (4) ◽  
pp. 374-387 ◽  
Author(s):  
Nguyen Thi Tuyet ◽  
Ngo Duc Thanh ◽  
Phan Van Tan
Keyword(s):  
Southeast Asia ◽  
Climate Models ◽  
Global Climate ◽  
Regional Climate ◽  
Global Climate Models ◽  
Red River ◽  
Observation Data ◽  
Red River Delta ◽  
North Central ◽  
Climate Downscaling

The study examined the performance of six regional climate experiments conducted under the framework of the Southeast Asia Regional Climate Downscaling/Coordinated Regional Climate Downscaling Experiment-Southeast Asia (SEACLID/CORDEX-SEA) project and their ensemble product (ENS) in simulating temperature at 2 m (T2m) and rainfall (R) in seven climatic sub-regions of Vietnam. The six experiments were named following the names of their driving Global Climate Models (GCMs), i.e., CNRM, CSIRO, ECEA, GFDL, HADG and MPI. The observation data for the period 1986–2005 from 66 stations in Vietnam were used to compare with the model outputs. Results showed that cold biases were prominent among the experiments and ENS well reproduced the seasonal cycle of temperature in the Northeast, Red River Delta, North Central and Central Highlands regions. For rainfall, all the experiments showed wet biases and CSIRO exhibited the best. A scoring system was elaborated to objectively rank the performance of the experiments and the ENS experiment was reported to be the best.

scholarly journals Virulence Pattern of Pyricularia oryzae Pathotypes Towards Blast Monogenic Lines

2021 ◽  
Vol 32 (3) ◽  
pp. 147-160
Author(s):  
Siti Norsuha Misman ◽  
Mohd Shahril Firdaus Ab Razak ◽  
Nur Syahirah Ahmad Sobri ◽  
Latiffah Zakaria
Keyword(s):  
Resistance Genes ◽  
Rice Blast ◽  
Blast Resistance ◽  
Rice Variety ◽  
Durable Resistance ◽  
Peninsular Malaysia ◽  
Pyricularia Oryzae ◽  
Blast Disease ◽  
Breeding Lines ◽  
Virulence Pattern

Rice blast caused by Pyricularia oryzae (P. oryzae) is one of the most serious diseases infecting rice worldwide. In the present study, virulence pattern of six P. oryzae pathotypes (P0.0, P0.2, P1.0, P3.0, P7.0 and P9.0) identified from the blast pathogen collected in Peninsular Malaysia, were evaluated using a set of 22 IRRI-bred blast resistance lines (IRBL) as well as to determine the resistance genes involved. The information on the virulence of the blast pathotypes and the resistance genes involved is important for breeding of new rice variety for durable resistance against blast disease. The IRBL was established from 22 monogenic lines, harbouring 22 resistance genes [Pia, Pib, Pii, Pit, Pi3, Pi5(t), Pish, Pi1, Pik, Pik-s, Pik-m, Pik-h, Pik-p, Pi7(t), Pi9, Piz, Piz-5, Piz-t, Pi19, Pi20(t), Pita-2, and Pita=Pi4(t)]. Based on the disease severity patterns, the tested pathotypes were avirulence towards seven IRBLs [IRBLi-F5, IRBLk-Ka, IRBLkh-K3, IRBLz-Fu, IRBLsh-S, IRBLPi7 (t) and IRBL9-W] of which these IRBLs harbouring Pii, Pik, Pik-h, Piz, Pish, Pi7(t) and Pi9 resistance genes, respectively. Therefore, the results suggested that the seven IRBLs carrying seven resistance genes [Pii, Pik, Pik-h, Piz, Pish, Pi7(t) and Pi9] would be suitable candidates of resistance genes to be incorporated in new breeding lines to combat the current blast pathotypes in the field.

scholarly journals Evaluation of GSMaP Satellite Precipitation Over Central VietNam in 2000-2010 Period and Correction Ability

2018 ◽  
Vol 34 (1S) ◽  
Author(s):  
Vu Thanh Hang ◽  
Pham Thi Thanh Nga ◽  
Pham Thanh Hà
Keyword(s):  
False Alarm ◽  
Correlation Coefficient ◽  
Daily Precipitation ◽  
Correlation Coefficients ◽  
Probability Of Detection ◽  
Monthly Precipitation ◽  
North Central ◽  
Satellite Precipitation ◽  
South Central ◽  
Central Vietnam

Abstract: Daily/Monthly precipitation of GSMaP is compared with observation at 10 stations over Central VietNam in 2000-2010 period. Evaluation indices used in this study include correlation coefficient (r), relative bias (B), probability of detection (POD) and false alarm ratio (FAR). The results show that the agreement of the first rainy month over 100mm and the maximum rainy month between GSMaP and observation, however, the duration of rainy months over 100mm of GSMaP is shorter than that of observation. GSMaP precipitationoften underestimates compared to observation in October-December  at almost stations.It can be seen that monthly correlation coefficients are often positive at almost stations when evaluating daily precipitation, the lower values normally are found in January and February. Positive relative biases are observed in April-September at most of North Central stations, while those often occur in July-September at South Central stations. Negative relative biases can be found in October until March of next year at almost stations. The good POD and FAR values are given at 0-6mm/day threshold and the worse values are found at 6-16mm/day threshold. After applying correction methods, the GSMaP precipitation is much better agreement with observation, especially in underestimated rainy months.       Key words:Precipitation, GSMaP, evaluation, correction.

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