Pathogenicity variation and mycelia compatibility groups in Sclerotina sclerotiorum (original) (raw)
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Pathogenicity Variation and Mycelial Compatibility Groups in Sclerotinia Sclerotiorum
Journal of Plant Protection Research, 2011
Pathogenicity Variation and Mycelial Compatibility Groups inSclerotinia SclerotiorumPopulation variability ofS. sclerotiorum, the causal agent of Sclerotinia stalk rot of sunflower, was determined by mycelial compatibility grouping (MCG) and pathogenicity variation comparison. To study mycelial compatibility grouping and pathogenicity variability, isolates ofS. sclerotiorumwere collected from sunflower fields in East, West Azerbaijan and Ardebil provinces of Iran. Among 186 isolates tested, 26 MCGs were identified and 46% were represented by single isolates. There were differences among MCGs comparing mycelial growth rate, sclerotial production on PDA and aggressiveness cause disease. Significant differences were detected in number of sclerotia, dry weight of sclerotia, mycelial growth rate and aggressiveness among MCGs (p < 0.001) regardless of their geographic origins. There was generally a poor correlation (r = 0.21, p ≤ 0.05) between sclerotia weight and number of sclerotia p...
Analysis of aggressiveness among isolates of Sclerotinia sclerotiorum from sunflower
Basal stem rot, caused by Sclerotinia sclerotiorum (Lib.) de Bary, is an important cause of yield loss in sunflower (Helianthus annuus L.). The main aim of the present study was to determine the aggressiveness of isolates of S. sclerotiorum on a single cultivar of sunflower using statistical methods. The aggressiveness of 108 isolates was determined on the sunflower hybrid cv. Iroflor. Plants were grown in a controlled condition. The experiment was arranged in a completely randomized design with three replications per isolate. The normality of the disease severity data was assessed in SAS (PROC UNIVARIATE; SAS Institute Inc., Cary, NC, USA). Analysis of variance (ANOVA) of the disease severity data was performed using the general linear model (GLM) procedure in the SAS software. The inoculation of sunflower stems with mycelial plugs and the measurement of lesion development were used to compare aggressiveness between isolates. Isolates of S. sclerotiorum differ significantly in aggressiveness on sunflower. Rank ordering of isolates indicated differences and lesion percentage ranged from 8 to 100 % depending to isolates. Screening of the aggressiveness of S. sclerotiorum isolates would be best conducted before their use in resistance screening to ensure that hypovirulent isolates are not used in resistance screening.
Jordan Journal of Agricultural Sciences, 2014
In this study, genetic structure and pathogenic diversity of Sclerotinia sclerotiorum, the causal agent of white cottony stem rot, were assessed through Mycelial Compatibility Groupings (MCGs) and comparison of isolate virulence. 65 isolates from six different hosts from three northern provinces of Iran (Golestan, Mazandaran and Gilan) were placed at 39 different mycelial compatibility groups. The observed MCGs differed within three regions. From all MCGs, 61.53% and 15.38% belonged to Mazandaran and Golestan and 10.25% and 12.82% were common between Mazandaran and Gillan and Mazandaran and Golestan, respectively. Shannon diversity index (Ho) of MCGs for the whole regions was 1.509 (Htot). Partition of total diversity (Htot) showed that 68% corresponded to a variation in diversity within S. sclerotiorum populations. Study on virulence was tested using a stem inoculation technique under greenhouse conditions. Evaluating of severity by two methods Stem Lesion Length and the Area Under Disease Progress Curve (AUDPC) showed that isolate virulence varied within the foue clade. Moreover, in most cases the differences in virulence of isolates within MCGs were significant. The data indicated that populations of S.sclerotiorum obtained from the studied regions were composed of a heterogeneous mix of MCGs, therefore the population structure of this pathogen as well as variations in virulence of isolates must be considered in disease management systems in these regions.
Pakistan Journal of Botany
Variability among 16 isolates of Sclerotinia sclerotiorum associated with the stem rot of chickpea collected from various localities of Pakistan is reported. The isolates varied in colony morphology, mycelial growth rate, sclerotium formation, sclerotial size and color. Variability among the isolates on the basis of their mycelial compatibility was also observed and out of 120 combinations more than half showed compatible reactions between either two isolates. Based on mycelial compatibility, 58% vegetative compatibility groups (VCG) were identified among all the isolates. Sixteen isolates were grouped into two clusters at 50% dissimilarity and both the clusters consisted 8 isolates in each case. The members of same cluster were compatible in most of the cases, whereas it was not true for the isolates with different background on the basis of cultural and morphological characteristics. A detailed study to investigate molecular and genetic basis of diversity in relation to antagonistic activity is suggested.
Response of sunflower genotypes to mid-stalk rot caused by Sclerotinia sclerotiorum
2022
Valkova, D., Jecheva, K. & Kiryakov, I. (2022). Response of sunflower genotypes to mid-stalk rot caused by Sclerotinia sclerotiorum. Bulg. J. Agric. Sci., 28 (1), 110–116 Phytopathological investigations of wild annual Helianthus annuus L. accessions and some hybrid progenies, derived from them were carried out to determine their reaction to two isolates of S. sclerotiorum under artificial inoculation of stems. Plants infection was carried out at the flowering stage. The analysis of variance for Stem disease score (SDS) and Lesions size (LS) showed a statistically significant interaction between isolate and genotype at P<0.05%. Differences in genotypes responses depending upon the isolates were established. The genotype × isolate interaction for the included wild accessions was significant, indicating that the wild sunflower genotypes differentially responded to both S. sclerotiorum isolates. The wild accessions E-129, E-115, E-110 and E-154 were consistent in terms of their resp...
Romanian agricultural research
Sclerotinia sclerotiorum is a cosmopolitan, homothallic fungus and is the most important causal agent of stem rot diseases in field crops of Iran. During 2006-2007, 65 isolates of the fungus were obtained from infected rapeseed, lettuce, bean, tomato, cucumber and wild Sinapis plants in various fields of North provinces of Iran. Genetic diversity between the isolates was investigated by PCR, using five microsatellite primer pairs. These divided the isolates into 9 groups with 25 clear polymorphic alleles. A high level of genetic diversity was observed at about 67.6% between some isolates. By mycelial compatibility grouping (MCG) tests, the isolates were classified into 39 groups of which 26 MCGs were individual. Molecular and phenotypic analyses results of all of the isolates (except MCG1, MCG4 and MCG23) were similar; however the isolates in MCG1, MCG4 and MCG23 groups, with variable microsatellite haplotypes, were morphologically dissimilar. The results shown here were possibly du...
2018
I want to express my gratitude to the following people for their much appreciated contribution to this dissertation: First and foremost, To the Almighty God, who provided me with the opportunity to undertake and persevere with this project. Without His grace and blessings, I would have never achieved this. To the wonderful Team McLaren at the University of the Free State, my supervisor, Prof. N.W. McLaren, my co-supervisor, L.A. Rothmann, and D. Van Rooyen for all the guidance, inspiration and motivation. To Ms V. Coetzee and A. Babooram, PANNAR Seed Co., Greytown and Dr Derick van Staden, DMS Genetics, Delmas, for providing trial sites, field maintenance and assistance.