scholarly journals Pathogenicity of Pythium species causing seed rot and damping-off in soybean under controlled conditions

2012 ◽  
Vol 91 ◽  
pp. 3-10 ◽  
Author(s):  
Lai Wei ◽  
Allen G. Xue ◽  
Elroy R. Cober ◽  
Carolyn Babcock ◽  
Jinxiu Zhang ◽  
...  
Keyword(s):  
Significant Influence ◽  
Pythium Ultimum ◽  
The Other ◽  
Effect Of Temperature ◽  
Pathogenic Species ◽  
Pythium Species ◽  
Damping Off ◽  
Highly Pathogenic ◽  
Seed Rot ◽  
Soybean Plants

Pythium species cause seed rot (SR) and damping-off (DO) in soybean worldwide. In a previous study, a number of Pythium species were isolated from infected soybean plants across Ontario and Quebec, but their comparative pathogenicities to soybean were not examined. In the present research, 24 isolates from eight Pythium spp. were evaluated for their pathogenicity in causing soybean SR and DO in a greenhouse environment. The effect of temperature on the ability of these isolates to cause SR was also studied. There were significant differences among the eight Pythium spp. for both SR and DO. When tested at 25°C, Pythium ultimum was the most pathogenic species, causing 97.0% SR and 46.4% DO, on average, in the two soybean cultivars used. Pythium aphanidermatum was the second most pathogenic species, resulting in 88.5% SR and 41.8% DO. The two species resulted in significantly greater SR and DO than the other six species tested and were considered highly pathogenic. Of the two cultivars used in these trials, ‘Beechwood’ was significantly more susceptible than ‘Nattawa’ to both SR and DO. Temperature had a significant influence on SR caused by Pythium spp. At all four temperatures tested (4°C, 12°C, 20°C and 28°C), P. ultimum was highly pathogenic, while P. arrenomanes, P. coloratum and P. dissotocum were the least pathogenic. The interactions between temperature and Pythium spp. were more pronounced for P. aphanidermatum, which showed an increased percentage of SR with an increase in temperature, and for P. irregulare, P. macrosporum and P. sylvaticum, which showed a decreased percentage of SR with an increase in temperature.

scholarly journals First report of Pythium ultimum causing damping-off of Sugar beet (Beta vulgaris. L) in Montana, USA

Plant Disease ◽  
2020 ◽  
Author(s):  
Mohamed Fizal Khan ◽  
Md. Ehsanul Haque ◽  
Peter Hakk ◽  
Md. Ziaur Rahman Bhuyian ◽  
Yangxi Liu ◽  
...  
Keyword(s):  
Sugar Beet ◽  
Beta Vulgaris ◽  
Pythium Ultimum ◽  
Pathogenicity Test ◽  
Damping Off ◽  
First Report ◽  
Beet Root ◽  
Pcr Products ◽  
Seed Rot ◽  
Sugar Beet Root

Sugar beet (Beta vulgaris L.) is a globally important crop for sugar. In May 2019, sugar beet seedlings were observed with wilting, lodging and a few were dead in Glendive (46.970170, -104.838204), Montana. Symptoms appeared near the soil line as the stem (hypocotyl) turned dark brown to black with characteristic thread-like infections which resembled Pythium damping-off. It affected approximately 10% of the growing seedlings. Diseased sugar beet root tissues were excised with a sterile scalpel and small pieces (10 mm²) were surface sterilized with 70 % ethanol for 30 seconds, rinsed twice with autoclaved water, air-dried and transferred to potato dextrose agar (PDA) media amended with pimaricin-vancomycin-PCNB (Conway, 1985). Four plates were incubated at 25° C in the dark (Masago et al., 1977) and two weeks later white, dense colony was observed (Zhang et al., 2018). The terminal smooth, globose oogonia (average 18.5 µm in diameter) and antheridia (average 14.5 × 9.5 µm) extended below the oogonium were observed via VWR N. A. 0.30 microscope. The morphological features of the four isolates were consistent with Pythium ultimum Trow (Watanabe, 2002). Genomic DNAs (NORGEN BIOTEK CORP, Fungi DNA Isolation Kit #26200) of four isolates were used for polymerase chain reaction (PCR) with the ITS6-ITS7 primers (Taheri et al., 2017). Subsequently, PCR products were flushed by E.Z.N.A ®Cycle Pure Kit, OMEGA and four samples were sent for Sanger sequencing to GenScript (GenScript, Piscataway, NJ). The sequences were identical and submitted to GenBank, NCBI (accession no. MN398593). The NCBI Blast analysis showed 100% sequence homology to Pythium ultimum with the following GenBank accessions; KF181451.1, KF181449.1 and AY598657.2. Pathogenicity test was done on sugar beet with the same isolates in the greenhouse. Two week old, pythium culture was mixed with vermiculite and perlite mixer (PRO-MIX FLX) in the plastic trays (24´´ x 15´´× 3˝), (22 °C, 75% Relaive Humidity). Sterile water (500 ml/each tray) was added in the mixer to provide sufficient moisture. Twenty seeds of cv. Hilleshog 4302 were sown in the tray, and the trays were replicated thrice with inoculated and mock treatments. Plants were watered as needed to maintain adequate soil moisture conducive for plant growth and disease development. Seven days after sowing, 50% and 100% germination was observed in the inoculated and control treatments, respectively. At the beginning of the second week, 30% post-emergence damping-off was observed in the inoculated treatments. Diseased seedlings were gently pulled out from the pots where similar symptoms were observed in the sugar beet seedlings as described previously. No incidence of disease was observed in mock-treated seedlings. Consistent reisolation of Pythium ultimum was morphologically and molecularly confirmed from the diseased seedlings, thus fulfilling Koch’s postulates. Pythium spp identification is prerequisite to develop effective management of pre and post-emergence damping-off. Pythium ultimum was previously reported in Nebraska to cause sugar beet seed rot and pre-emergence damping-off (Harvenson 2006). To our knowledge, this is the first report of Pythium ultimum causing damping-off on sugar beet in the Sidney factory district in Montana.

scholarly journals Antifungal Activity of Selected IndigenousPseudomonasandBacillusfrom the Soybean Rhizosphere

2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
M. León ◽  
P. M. Yaryura ◽  
M. S. Montecchia ◽  
A. I. Hernández ◽  
O. S. Correa ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Seedling Emergence ◽  
Pythium Ultimum ◽  
Phytopathogenic Fungi ◽  
Soybean Seeds ◽  
Damping Off ◽  
Bacterial Strains ◽  
Protected Plants ◽  
Soybean Plants

The purpose of this study was to isolate and select indigenous soilPseudomonasandBacillusbacteria capable of developing multiple mechanisms of action related to the biocontrol of phytopathogenic fungi affecting soybean crops. The screening procedure consisted of antagonism tests against a panel of phytopathogenic fungi, taxonomic identification, detection by PCR of several genes related to antifungal activity, in vitro detection of the antifungal products, and root colonization assays. Two isolates, identified and designated asPseudomonas fluorescensBNM296 andBacillus amyloliquefaciensBNM340, were selected for further studies. These isolates protected plants against the damping-off caused byPythium ultimumand were able to increase the seedling emergence rate after inoculation of soybean seeds with each bacterium. Also, the shoot nitrogen content was higher in plants when seeds were inoculated with BNM296. The polyphasic approach of this work allowed us to select two indigenous bacterial strains that promoted the early development of soybean plants.

scholarly journals Selection-Based heritability of Resistance to Pythium Ultimum in Safflower

2014 ◽  
Vol 66 (1) ◽  
pp. 109-117
Author(s):  
Elham Nikmanesh ◽  
Mohammadhadi Pahlevani ◽  
Seyed Esmaeil Razavi
Keyword(s):  
Seedling Emergence ◽  
Pythium Ultimum ◽  
Realized Heritability ◽  
Breeding Methods ◽  
Damping Off ◽  
Seed Rot ◽  
Selection For ◽  
Severity Of The Disease ◽  
Germinating Seeds ◽  
Considerable Damage

Abstract Damping-off disease caused by Pythium ultimum can kill both germinating seeds and young seedlings and cause considerable damage in saflower cultivation. An estimation of heritability lets saflower breeders determine the most effective method for improving seedling emergence in soils infected with P. ultimum, the causal agent of seed rot and damping-off. Two cycles of selection were performed to estimate the realized heritability of resistance to the pathogen in five safflower populations. Undamaged seedlings were selected as resistant individuals and were kept to produce seed. The results showed that selection for two consecutive generations increased the emergence of seedlings in Pythium-infected soil from 46 to 53 %. The heritability estimates varied between 1.72 and 77.66 % over the genotypes and environments, in inverse proportion to the severity of the disease. Estimates of heritabilities showed that genes conferring resistance to P. ultimum in safflower are highly heritable and would respond to selection breeding, particularly in some of the studied genotypes, like Isfahan and Zarghan259. However, different breeding methods must be explored for other genotypes.

Chickpea seed rot and damping-off caused by metalaxyl-resistant Pythium ultimum and its management with ethaboxam

Plant Disease ◽  
2020 ◽  
Author(s):  
Moying Wang ◽  
Stephen Van Vleet ◽  
Rebecca McGee ◽  
Timothy Carl Paulitz ◽  
Lyndon D. Porter ◽  
...  
Keyword(s):  
Field Tests ◽  
Pythium Ultimum ◽  
Damping Off ◽  
Fitness Costs ◽  
Seed Treatments ◽  
Dryland Agriculture ◽  
Metalaxyl Resistance ◽  
Resistance Trait ◽  
Seed Rot ◽  
Northern Idaho

Metalaxyl and its isomer mefenoxam have been the primary fungicides used as seed treatments in managing Pythium seed rot and damping-off of chickpea. However, recent outbreaks of seed rot and damping-off of metalaxyl-treated chickpea seeds were found in the dryland agriculture regions of southeastern Washington and northern Idaho. Pythium spp. isolated from rotten seeds and associated soils showed high levels of resistance to metalaxyl. Large proportions (31 to 91%) of Pythium isolates resistant to metalaxyl were detected in areas where severe chickpea damping-off occurred and were observed in commercial chickpea fields over several years. All metalaxyl-resistant isolates were identified as P. ultimum var. ultimum. The metalaxyl resistance trait measured by EC50 values was stable over 10 generations in the absence of metalaxyl, and no observable fitness costs were associated with metalaxyl resistance. Under controlled conditions, metalaxyl treatments failed to protect chickpea seeds from seed rot and damping-off following inoculation with metalaxyl-resistant Pythium isolates. In culture, ethaboxam inhibited mycelial growth of metalaxyl-resistant, as well as metalaxyl-sensitive isolates. Greenhouse and field tests showed that ethaboxam is effective in managing metalaxyl-resistant Pythium. Ethaboxam in combination with metalaxyl is now commonly applied as seed treatments in commercial chickpea production.

THE EFFECT OF EVENT AND PUBLICITY TOWARDS BRAND AWARENESS ON FINANCIAL SERVICE AUTHORITY (OJK)

2017 ◽  
Vol 2 ◽  
pp. 281-292
Author(s):  
Donant Alananto Iskandar ◽  
Siti Dewi Sri Ratna Sari
Keyword(s):  
Public Relations ◽  
Significant Influence ◽  
Quantitative Method ◽  
Statistical Approach ◽  
Financial Service ◽  
The Other ◽  
Brand Awareness ◽  
Financial Service Authority ◽  
Other Hand ◽  
The People

This study aims to find out the effect of event and publicity towards brand awareness on Indonesia Financial Service Authority, usually called with its abbreviation OJK. The research background is because OJK was newly established as a financial service authority, replacing Bank Indonesia. Therefore, exploring the awareness of the people about the function of OJK is interesting to be a research subject.This method used in this study is the quantitative method with 82 samples as the questionnaire respondents. The population chosen was an OJK’s event held at LPPI and Indonesia Banking School with 122 participants. Validity, reliability, normality, multicollinearity, heteroskedasticity, correlation, determination, regression, hypothesis and ANOVA tests are used as a statistical approach in order to define the outcome of the survey. The results of this study are both event and publicity have a positive and a significant influence towards brand awareness partially and simultaneously. As the conclusion, OJK should continue its programs. On the other hand, OJK should find another public relations strategy to accelerate people awareness about the duties of OJK. Keywords: Event, Publicity, Brand Awareness

scholarly journals The Respiration of some Planktonic copepods II. The Effect Of Temperature

1953 ◽  
Vol 31 (3) ◽  
pp. 447-460 ◽  
Author(s):  
D. T. Gauld ◽  
J. E. G. Raymont
Keyword(s):  
Respiratory Rate ◽  
The Body ◽  
The Other ◽  
Effect Of Temperature ◽  
Acartia Clausi ◽  
Temora Longicornis ◽  
Different Temperatures ◽  
Planktonic Copepods ◽  
The Difference ◽  
The Relationship

The respiratory rates of three species of planktonic copepods, Acartia clausi, Centropages hamatus and Temora longicornis, were measured at four different temperatures.The relationship between respiratory rate and temperature was found to be similar to that previously found for Calanus, although the slope of the curves differed in the different species.The observations on Centropages at 13 and 170 C. can be divided into two groups and it is suggested that the differences are due to the use of copepods from two different generations.The relationship between the respiratory rates and lengths of Acartia and Centropages agreed very well with that previously found for other species. That for Temora was rather different: the difference is probably due to the distinct difference in the shape of the body of Temora from those of the other species.The application of these measurements to estimates of the food requirements of the copepods is discussed.

scholarly journals Identifying key processes and sectors in the interaction between climate and socio-economic systems: a review toward integrating Earth–human systems

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Kaoru Tachiiri ◽  
Xuanming Su ◽  
Ken’ichi Matsumoto
Keyword(s):  
Ecosystem Services ◽  
Gross Domestic Product ◽  
Significant Influence ◽  
Ghg Emissions ◽  
Climate Impacts ◽  
Ecological Impacts ◽  
The Other ◽  
Economic Damage ◽  
Economic Systems ◽  
The Impact

AbstractFor the purpose of identifying the key processes and sectors involved in the interaction between Earth and socio-economic systems, we review existing studies on those processes/sectors through which the climate impacts socio-economic systems, which then in turn affect the climate. For each process/sector, we review the direct physical and ecological impacts and, if available, the impact on the economy and greenhouse gas (GHG) emissions. Based on this review, land sector is identified as the process with the most significant impact on GHG emissions, while labor productivity has the largest impact on the gross domestic product (GDP). On the other hand, the energy sector, due to the increase in the demand for cooling, will have increased GHG emissions. Water resources, sea level rise, natural disasters, ecosystem services, and diseases also show the potential to have a significant influence on GHG emissions and GDP, although for most of these, a large effect was reported only by a limited number of studies. As a result, more studies are required to verify their influence in terms of feedbacks to the climate. In addition, although the economic damage arising from migration and conflict is uncertain, they should be treated as potentially damaging processes.

scholarly journals Influence of Ceramic Particles Character on Resulted Properties of Zinc-Hydroxyapatite/Monetite Composites

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 499
Author(s):  
Klára Hosová ◽  
Jan Pinc ◽  
Andrea Školáková ◽  
Vilém Bartůněk ◽  
Petr Veřtát ◽  
...  
Keyword(s):  
Significant Influence ◽  
Degradation Rate ◽  
Point Of View ◽  
The Other ◽  
Ceramic Particles ◽  
Biological Aspects ◽  
Strength And Ductility

Zinc and its alloys seem to be promising candidates for biodegradable applications. Those materials are often modified by other elements or compounds in order to enhance their properties. The combination of zinc and apatites is challenging for several reasons. However, the advantages connected with the biological aspects suggest the need for further research into such materials. In this study, three zinc-based composites with 4 and 8 wt. % of nanohydroxyapatite or nanomonetite (Zn-4MO, Zn-4HA, Zn-8HA) were prepared by sintering and subsequent extrusion. Materials prepared in this way were characterized from the microstructural, mechanical and corrosion point of view. The obtained results showed a significant influence of particle character (amount and morphology) on the strength and ductility of the prepared materials. In case of Zn-4MO, the presence of monetite significantly increased the ductility compared with the other materials. In addition, the increment of the degradation rate caused by the presence of monetite was observed as well. All obtained results pointed out to significant advantages of monetite for the preparation of Zn-apatite composites compared with hydroxyapatite.

scholarly journals Pathogenicity and Virulence of Pythium Species Obtained from Forest Nursery Soils on Douglas-Fir Seedlings

Plant Disease ◽  
2013 ◽  
Vol 97 (6) ◽  
pp. 744-748 ◽  
Author(s):  
Jerry E. Weiland ◽  
Bryan R. Beck ◽  
Anne Davis
Keyword(s):  
Pseudotsuga Menziesii ◽  
Seedling Survival ◽  
The United States ◽  
Douglas Fir ◽  
Tree Seedlings ◽  
Pythium Species ◽  
Forest Nursery ◽  
Damping Off ◽  
Greenhouse Study ◽  
Forest Nurseries

Pythium species are common soilborne oomycetes that occur in forest nursery soils throughout the United States. Numerous species have been described from nursery soils. However, with the exception of P. aphanidermatum, P. irregulare, P. sylvaticum, and P. ultimum, little is known about the potential for other Pythium species found in nursery soils to cause damping-off of tree seedlings. A greenhouse study was conducted to evaluate the pathogenicity and virulence of 44 Pythium isolates representing 16 species that were originally recovered from soil at three forest nurseries in Washington and Oregon. Seeds of Douglas-fir (Pseudotsuga menziesii) were planted into soil infested with each of the isolates. Seedling survival, the number of surviving seedlings with necrotic root lesions, and taproot length were evaluated 4 weeks later. Responses of Douglas-fir to inoculation varied significantly depending on Pythium species and isolate. Eight species (P. dissotocum, P. irregulare, P. aff. macrosporum, P. mamillatum, P. aff. oopapillum, P. rostratifingens, P. sylvaticum, and P. ultimum var. ultimum) significantly reduced the number of surviving seedlings compared to the noninoculated treatment. However, all Pythium species caused a greater percentage of seedlings to develop root lesions (total mean 40%) than was observed from noninoculated seedlings (17%). Taproot length varied little among Pythium treatments and was not a useful character for evaluating pathogenicity. Results confirm the ability of P. irregulare, P. mamillatum, and P. ultimum var. ultimum to cause damping-off of Douglas-fir seedlings, and are indicative that other species such as P. dissotocum, P. aff. macrosporum, P. aff. oopapillum, P. rostratifingens, and P. sylvaticum may also be responsible for seedling loss.

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