scholarly journals Characterization and virulence determination of Colletotrichum kahawae isolates from Gidami, Western Ethiopia

2021 ◽  
Vol 5 (1) ◽  
pp. 004-013
Author(s):  
W Zenebe ◽  
T Daniel ◽  
G Weyessa

Coffee is one of the most essential crops that generate income for Ethiopian economic growth. However, its production faced with many factors primarily biotic entities. Among these, the fungal pathogen /Colletotrichum kahawae/ that induce coffee berry disease (CBD) is the main constraint of coffee production in the country. The pathogen is a very specialized and infects the green berries/fiscal par/which diminishes the income gained from it and disturbs the country’s economy in general and the producers in particular. Regarding to the disease level and related factors, little information is available in Western Ethiopia. Hence, this study was initiated to assess the magnitude of CBD in coffee fields, to characterize and evaluate the virulence of C. kahawae isolates from the study areas of Gidami district. Assessment was done in 9 selected kebeles of 45 total farms starting from July 2017. The results indicated that CBD was prevalence in all assessed areas with the range of 66% to 86% and 16% to 50% disease incidence and severity index (SI), respectively. The highest CBD intensity was observed in higher altitude with a significant positive correlation between disease incidence (r = 0.61) and severity (r = 0.55). Macro and microscopic characterization results revealed isolates diversity in terms of colony color, density, mycelia growth rate and conidial production. Moreover, mycelia growth rate differs significantly (p < 0.001) in the range between 2.2 to 4.3 mm/24 hrs. Similarly, the sporulation capacity widely ranged from 186.1 to 572.3 spores/ml. This were strongly agreed with the virulence test that revealed significant variation (p < 0.001) among isolates and infection percentage also ranged between 34.8% and 88.7%. In all, the study was not only showed the CBD is very important disease of coffee in the study area but also determines the virulence disparity among isolates. To be honest, the diversity/identity of C. kahawae isolates should be confirmed using more other reliable methods thru including additional sample areas as well.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seungho Lee ◽  
Jae Bum Park ◽  
Kyung-Jong Lee ◽  
Seunghon Ham ◽  
Inchul Jeong

AbstractThis study aimed to investigate the association between work organization and the trajectories of insomnia patterns among night shift workers in a hospital. The health examination data of hospital workers, recorded from January 2014 to December 2018, were collected; 6765 records of 2615 night shift workers were included. Insomnia was defined as a score of ≥ 15 on the Insomnia Severity Index (ISI). Participants were categorized into five groups according to insomnia patterns derived from the analysis of their ISI scores. Work organization and socio-demographic characteristics were also investigated. Generalized estimating equation models and linear mixed models were constructed to analyze the longitudinal data. Of the total participants, 53.0% reported insomnia at least once during the follow-up period. The lack of nap opportunities and work-time control was associated with the occurrence of insomnia, whereas more than 5 years of shift work experience was related to the resolution of insomnia. All work-related factors were significantly related to insomnia risk; however, the effects were not significant in the sustained insomnia group. Although sleep problems are inevitable in night shift workers, well-designed work schedules and better work organization can help reduce the occurrence of insomnia among them.


2021 ◽  
Vol 38 (1) ◽  
pp. 20-37
Author(s):  
Yohana Patricia Anama ◽  
Ricardo Díaz ◽  
David Esteban Duarte-Alvarado ◽  
Tulio Cesar Lagos-Burbano

Fusarium oxysporum is one of the most limiting fungal pathogens of lulo crop. To determine its pathogenicity, this work morphologically and pathogenically characterized F. oxysporum isolates from different lulo-growing municipalities of the Department of Nariño. Twenty isolates were evaluated through a completely randomized design with two factors and three replicates per treatment, including a control. The first factor corresponded to 20 isolates of F. oxysporum and the second to 10 lulo genotypes. The morphological characterization involved determining growth rate (GR), color (CO), mycelial type (MT), medium coloration (Mc), shape (Sh), size (S), number (N) of macroconidial (Ma) and microconidial (Mi) septa, presence of chlamydospores (PC), and chlamydospore shape (CS). Moreover, the pathogenic characterization was based on the incubation period (IP), absolute growth rate (AGR), disease severity (DS), disease incidence (I), and vascular discoloration (VD). The morphological characterization demonstrated that all isolates corresponded to F. oxysporum. For IP, genotype G1 showed the lowest average at 18 days. For AGR, genotype G2 had the lowest height increase at 0.05 cm.day-1. For DS, genotype G1 reached the highest severity level (level 9) and a disease incidence of 100%. This study provides the first report of the special form of F. oxysporum f. sp. quitoense in Nariño. Solanum hirtum, Solanum sessiliflorum, and Solanum estramonifolium were resistant to the isolates evaluated, demonstrating that wild species should be considered as sources of resistance for breeding programs aiming to obtain resistant commercial genotypes.


Plant Disease ◽  
2021 ◽  
Author(s):  
Brian Mueller ◽  
Carol Groves ◽  
Damon L. Smith

Fusarium graminearum commonly causes Fusarium head blight (FHB) on wheat, barley, rice, and oats. Fusarium graminearum produces nivalenol and deoxynivalenol (DON) and forms derivatives of DON based on its acetylation sites. The fungus is profiled into chemotypes based on DON derivative chemotypes (3 acetyldeoxynivalenol (3ADON) chemotype; 15 acetyldeoxynivalenol (15ADON) chemotype) and/or the nivalenol (NIV) chemotype. The current study assessed the Fusarium population found on wheat and the chemotype profile of the isolates collected from 2016 and 2017 in Wisconsin. Fusarium graminearum was isolated from all locations sampled in both 2016 and 2017. Fusarium culmorum was isolated only from Door County in 2016. Over both growing seasons, 91% of isolates were identified as the 15ADON chemotype while 9% of isolates were identified as the 3ADON chemotype. Aggressiveness was quantified by area under disease progress curve (AUDPC). The isolates with the highest AUDPC values were from the highest wheat producing cropping districts in the state. Deoxynivalenol production in grain and sporulation and growth rate in vitro were compared to aggressiveness in the greenhouse. Our results showed that 3ADON isolates in Wisconsin were among the highest in sporulation capacity, growth rate, and DON production in grain. However, there were no significant differences in aggressiveness between the 3ADON and 15ADON isolates. The results of this research detail the baseline frequency and distribution of 3ADON and 15ADON chemotypes observed in Wisconsin. Chemotype distributions within populations of F. graminearum in Wisconsin should continue to be monitored in the future.


2018 ◽  
Vol 44 (3) ◽  
pp. 271-273 ◽  
Author(s):  
Pamela Maia Dirchwolf ◽  
Susana Alejandra Gutiérrez ◽  
Marcelo Aníbal Carmona3

ABSTRACT Rice grain discoloration affects grain yield and quality. Corrientes is the main rice producing province in Argentina. Previous studies were carried out in this province, where only panicle incidence (PI) was evaluated. In view of the need to obtain more agronomic parameters to more exhaustively investigate the effects caused by this disease, the present study was carried out to evaluate panicle incidence (PI), percentage of discolored grains per panicle (GD), weight loss (WL), disease severity index (DSI) and sterility (S) in eight rice genotypes. Although PI and GD are estimated as disease incidence, both were significantly different. GD is obtained by the grain-by-grain evaluation, while PI considers a panicle diseased when the latter presents at least one spotted grain; thus, this last method overestimates the disease incidence. The genotype IRGA 424 recorded maximum and minimum GD and S values, which may be explained by different sowing dates in different regions in the province, with their corresponding environmental conditions during the critical period of the infection and during spikelet formation. WL and DSI had lower values than those reported by other authors, which indicates that the effects of rice grain discoloration on these parameters in Corrientes Province, Argentina, are less severe than in other rice cultivating countries.


2019 ◽  
Vol 17 (04) ◽  
pp. 346-351
Author(s):  
SamanthiKumari Wasala ◽  
Sumudu I. Senevirathne ◽  
Jayantha Bandara Senanayake ◽  
Anuradini Navoditha

AbstractWild relative of okra, Abelmoschus angulosus Wall. ex Wight &amp; Arn. was identified as a resistant germplasm for Okra Yellow Vein Mosaic Virus (OYVMV) which is the devastating disease for okra cultivation in Sri Lanka. The mode of resistance of OYVMV in A. angulosus was studied with the aim of tagging responsible genes for the disease resistance. Wide hybridization was performed between A. angulosus and highly virus susceptible A. esculentus variety, MI-7. Very poor seed setting was observed in F1 and F2 generations due to post zygotic abortion. Disease screening was carried out using F1 and F2:3 populations along with parents in the field under induced disease pressure. Disease severity index and area under disease progress curve were calculated to measure disease severity. Number of genes segregating for OYVMV disease resistance was calculated for the F2:3 generation. Modified Wright's formula was used to estimate the effective gene number and mode of inheritance by a quantitative method. A χ2 test was performed for qualitative analysis. Plants of A. angulosus were totally free of virus incidence while 100% disease incidence was observed in the variety MI-7. F2:3 population showed between and within progeny segregation for disease incidence. Results indicated that the disease susceptibility was dominant over resistance. χ2 analysis revealed that the segregation of disease severity was significantly fit to the gene model of 9:6:1 (χ2 = 0.1757 at P ≤ 0.05) suggesting the disease resistance in A. angulosus is governing by two recessive genes in an additive manner. Result was confirmed by the quantitative analysis.


2012 ◽  
Vol 63 (4) ◽  
pp. 351 ◽  
Author(s):  
B. H. Yu ◽  
Z. B. Nan ◽  
Y. Z. Li ◽  
H. L. Lin

Yellow stunt and root rot caused by Embellisia astragali are major factors contributing to declining yields of standing milkvetch (Astragalus adsurgens). The resistance of ten varieties of standing milkvetch to E. astragali was evaluated under laboratory, greenhouse, and field conditions. Seed germination/emergence, shoot and root length, plant dry weight, disease incidence, mortality, and disease severity index were monitored. The results show that Shanxi and Zhongsha No. 1 varieties had the best agronomic traits and lowest levels of disease in all experiments, while the varieties Neimeng and Ningxia had the highest susceptibility to disease. Germination/emergence differed significantly (P < 0.05) between varieties after inoculation, and compared with the control, germination/emergence of inoculated treatments of nine varieties decreased on average by 1.5% in laboratory experiments and by 4.1% in greenhouse experiments at 15 days after inoculation. Inoculation reduced shoot length by an average of 24.4% and 41.5% (P < 0.05) in laboratory and greenhouse experiments, respectively, in six of ten varieties. All varieties showed significantly (P < 0.05) lower plant dry weight following inoculation, with reductions ranging from 0.3 to 0.6 mg in the laboratory and from 82.6 to 149.4 mg in the greenhouse. Resistance to the pathogen was evaluated on the basis of disease incidence, a disease severity index (DSI), and mortality; varieties showing different resistance were grouped using cluster analysis. There were significant correlations between the results of laboratory and greenhouse experiments (r = 0.79; P < 0.01) and between greenhouse and field experiments (r = 0.83; P < 0.01) across all varieties. Multiple regression analysis between laboratory/greenhouse and field experiments on DSI suggested that screening in the laboratory/greenhouse could be an alternative method of rapidly estimating DSI under field conditions.


2021 ◽  
pp. 151-157

Introduction: Injuries are the causes of irreparable damages and costs in urban and rural settings. Preventive procedures are effective if correct related information is gathered and provided. Therefore, this study aimed to investigate the injury patterns and related factors in a large teaching hospital. Methods: The current cross-sectional study was conducted at Edalatian Emergency Center, Mashhad, Iran, in 2016. All study subjects were extracted from the Hospital Information System (HIS).The demographic characteristics and injuries-related factors of 6,350 patients were extracted from the HIS. The extracted variables were emergency severity index (ESI), type of referral, referral reason, insurance organizations, age, anatomic site of injuries, and month of referral. The data were analyzed in SPSS software (version 21) using the descriptive statistics method (frequency and percentage). Results: The majority of the study population was composed of males (%76.4). In total, 98.3% of the patients were classified into the semi-urgent and non-urgent levels, and 75.6% of the cases were affected in the right upper extremity. The most common age group was between 10-20 (69.4%) years, and the majority of the cases were admitted in June, July, and August. Conclusion: The current study determined the pattern and most important reasons for injuries' referral to an emergency department. Accordingly, the injuries were more frequent in the young people and active human force in our community. Furthermore, there was a significant difference among the frequencies of injury incidence in the summer holidays. It seems necessary to develop preventive procedures for injuries.


Author(s):  
Ngoh Dooh Jules Patrice ◽  
Deurnaye Placide ◽  
Abdoul Madjerembe ◽  
Mbou T. Pavel Rony ◽  
Djongnang Gabriel ◽  
...  

Aims: The aim of this work was to evaluate effect of Mancozeb 80 WP against Colletotrichum gloeosporioides, the agent responsible of anthracnose of cashew tree (Anacardium occidentale  L.). Study Design: The experimental design was in completely randomized blocks with three replications. Place and Duration of Study: in vitro and in vivo experiments were performed in Laboratory of  Department of Biological Sciences, University of Maroua during six months. Field trial was carried out in Kelo, Chad during three months. Methodology: Isolates were obtained from diseased organs (leaves and fruits) from Kélo in Chad and Maroua in Cameroon. The concentrations used in the laboratory were C1 (5 mg/ml), C2 (0.5 mg/ml), C3 (0.05 mg/ml), C4 (0.005 mg/ml), C5 (0.0 mg/ml). Radial growth, sporulation, conidial germination and pathogenicity were used to characterize and evaluate the effect of Mancozeb on the isolates in vitro. The preventive test was performed on three-month-old plants previously treated with Mancozeb. The concentration of 5 g/l was applied to the field and the incidence and severity were used to calculate the AUIPC (Area Under Disease Incidence Progress Curve) and AUSiPC (Area Under Disease Severity Index Progress Curve) curves. Results: Mancozeb reduced radial growth of all isolates at concentrations C1 (5 mg/ml), C2 (0.5 mg/ml) and C3 (0.05 mg/ml). The percentages of inhibition ranged from 50 to 100%. Mancozeb 80 WP completely (100%) inhibited the germination of C. gloeosporioides conidia in vitro. Mancozeb has protected cashew plants in vivo at the concentration C1 (5 mg/ml). AUIPC and AUSiPC were higher on control plants and lower on Mancozeb-treated plants. Conclusion: Mancozeb 80 WP may be associated in integrated pest management strategy against anthracnose.


2020 ◽  
Author(s):  
Md. Hamidu Rahman ◽  
Niaz Mahmud Zafri ◽  
Fajle Rabbi Ashik ◽  
Md Waliullah

The outbreak of the COVID-19 pandemic is an unprecedented shock throughout the world which leads to generate a massive social, human, and economic crisis. However, there is a lack of research on geographic modeling of COVID-19 as well as identification of contributory factors affecting the COVID-19 in the context of developing countries. To fulfill the gap, this study aimed to identify the potential factors affecting the COVID-19 incidence rates at the district-level in Bangladesh using spatial regression model (SRM). Therefore, data related to 32 demographic, economic, weather, built environment, health, and facilities related factors were collected and analyzed to explain the spatial variability of this disease incidence. Three global (Ordinary least squares (OLS), spatial lag model (SLM) and spatial error model (SEM)) and one local (geographically weighted regression (GWR)) SRMs were developed in this study. The results of the models showed that four factors significantly affected the COVID-19 incidence rates in Bangladesh. Those four factors are urban population percentage, monthly consumption, number of health workers, and distance from the capital. Among the four developed models, the GWR model performed the best in explaining the variation of COVID-19 incidence rates across Bangladesh with a R square value of 78.6%. Findings from this research offer a better insight into the COVID-19 situation and would help to develop policies aimed to prevent the future epidemic crisis.


2021 ◽  
Author(s):  
Meng An ◽  
Yuanyuan Liu ◽  
Yan Zhang ◽  
Chengye Che ◽  
Jie Zhang ◽  
...  

Abstract PurposeObjective to investigate the progress and related factors for myopia in school-aged children in the Economic and Technological Development Zone of Qingdao. MethodsA total of 320 myopic students (aged 10-15 years; grade 3 to 8), who were willing to cooperate for a long time follow-up, were enrolled in the longitudinal survey. Participants underwent a comprehensive ophthalmic examination included uncorrected visual acuity, corrected visual acuity, slit lamp examination, and cycloplegic autorefraction in January 2017 and 2019, respectively. At the end of the follow-up, the information of near work, outdoor activities and other related factors were collected through a questionnaire. Qualified questionnaires were obtained in 296 (92.50%) students. All the data were entered, cleaned and analyzed by EpiData3.0. SPSS 20.0 statistical software was used for data general description, univariate and multiple logistic regression analysis.Results1. The baseline mean spherical equivalent of all students decreased from -2.29±1.16D in 2017 to -3.45±1.34D at the end of 2 years follow-up in 2019. The annual average growth of myopia was -0.58D (t=7.708, P<0.001). The growth rate of myopia in Grade 6 was faster than that in other grades, and the difference was statistically significant (F=8.236, P=0.003). 2. Both boys and girls showed significant myopia progress after 2 year follow-up. (Boys: t=6.342, P<0.001; Girls: t=4.888, P<0.001). However, we have not found significant difference in the growth rate between them.3. The proportion of two myopic parent was the highest in this sample, followed by one myopic parent, and no myopic parent was the lowest (c2=27.919, P<0.001). 4. The higher the grade, the more time the students spend on near work (F=2.988, P=0.012) and the less time they spend on outdoor activities. (F=2.290, P=0.046). We did not find that the myopia progression was related with Age, Sex, Parent myopia, Near work time and Outdoor activity time.ConclusionsIn this study, the Grade 6 adolescents had relatively rapid progression for myopia than other age groups. There was no significant difference in the progression of myopia between girls and boys. We did not find that the progression of myopia was related with Age, Sex, Parental myopia, Near work time and Outdoor activities time.


Sign in / Sign up

Export Citation Format

Share Document