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Ninety one monoconidial Bipolaris isolates were obtained from lesions on different parts of rice in different locations of Mazandaran province during the summer of 2009. Bipolaris species were identified using morphological features such as color and shape of colony and color and size of conidia and conidiophores. The isolates were separated into two species; 85 (93.4%) isolates belonged to Bipolaris oryzae and the remaining 6 (6.6%) isolates to Bipolaris cynodontis. Therefore B. oryzae is regarded as the major cause of rice brown spot disease in Mazandaran province. In order to analyze genetic diversity among B. oryzae isolates, 71 isolates were subjected to fingerprinting analysis by rep-PCR using BOX and REP primers. In cluster analysis, 15 clonal lineages and 54 haplotypes were identified. The largest clonal lineage contained with 36 haplotypes was the most common lineage. These results also indicate a relatively high level of genetic diversity among B. oryzae isolates. Also, pathogenicity test of a few B. oryzae isolates (12 isolates) was conducted under greenhouse condition and showed that those isolates were pathogenic to rice seedlings of cv. Tarom. All isolates produced some leaf spots 24 h after inoculation.

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Anthracnose disease caused by Ophiognomonia leptostyla, is the most important and widespread fungal disease on Juglans regia. Walnut disease symptomatic samples were collected from different provinces of Iran, during 2015–2016. Fungal isolates were identified based on ITS-rDNA sequence data. Variance analysis of colony growth rate (mm/day) and acervulus density on medium, was significant. Acervulus density on medium was strongly correlated with colony growth rate. The Max acervulus density was 60% and > 80% for Hamedan and Mazandaran isolates respectively. The virulence of six selected isolates was examined on cv. Chandler. Virulence indices including spot diameter, disease severity, spot area average and logistic infection rate except spot number index, could successfully detect significant differences among isolates. SA-SE1 isolate from Mazandaran showed significantly the most virulence indices: disease severity (%), spot area and logistic infection rate. For the other five isolates, four significant levels in all virulence indices were observed. In summary after this isolate, other isolates including TA-ZY21, LA-SY21, U94-SR1, HA-GH22 and MA-K1 were placed in the next steps of virulence ranking. There was insignificant correlation between colony growth rate and disease severity. However, the acervulus density and disease severity were significantly correlated implying the importance of acervular conidial inoculum in secondary disease cycle progress. Disease severity was strongly correlated with number of spots, spot diameter and logistic infection rate. Disease severity was also negatively correlated with Mid-time (time to progress 50%). Moreover, there was positive relationship between logistic infection rate and three traits: number of spots, spot diameter and spot area average. This study was the first of the disease virulence components on cv. Chandler in Iran.
 

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Anthracnose caused by Colletotrichum gloeosporioides s. l. is one of the most important diseases of citrus in northern Iran. To study the genetic structure of C. gloeosporioides s. l. from citrusspp., infected samples were collected from three citrus cultivating regions of northern Iran, during the summer of 2009. Fifty one monoconidial isolates were used as the objective of REP- and BOX-PCR fingerprintings. Eight fingerprinting groups were observed in the constructed phenogram. The largest proportion (94.37%) of total genetic diversity (H_t) was attributed to diversity within populations (H_s). Estimates of Nei’s genetic similarity and distances exhibited the high level of similarity among three populations. The value of gene flow, N_M= 8.4, indicates that there is low limitation to gene flow among these geographically distant populations, which make these groups genetically homogenous. The results indicate that the three geographic populations are not developing independently and can be part of a Mega-population. Forty three isolates were divided into 19 groups in the phenogram constructed by combination of morphological characteristics data. Estimation of correlation between morphologic and rep-PCR matrixes indicated a weak and non-significant correlation between morphology and rep-PCR haplotypes (r= 0.2, P= 0.992). Fifty one isolates were examined to clarify their sexual behavior. Eight isolates were identified as homothallic and 14 successful outcrosses were observed among self-sterile isolates.

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Use of nanoparticles in food packaging can be an effective step to reduce waste from pathogens and increase the shelf life of various products. The aim of this study was to investigate the antifungal effect of low-density polyethylene nanocomposite film containing nano clay halloysite/carvacrol hybrid and chitosan on pathogenic fungi including Aspergillus niger, Aspergillus flavus, Boterytis cinera, Penicillium Sp. and Rhizopus oryzae, the main cause of post-harvest rot of agricultural products. In this study, the nanocomposite films based on Low-density polyethylene containing 1.5 & 3% nano clay halloysite/carvacrol and 1 & 2% chitosan were produced by mixing them in a twin-screw extruder following by blowing film machine. The effect of these produced nanocomposites were then evaluated on the growth of five pathogenic fungal species. Based on the results of analysis of variance, it was found that the growth rate of the five studied fungal species was significantly affected by use of Nano clay Halloysite/carvacrol, so that the highest percentage of inhibition was related to the film containing 3% nano clay halloysite/carvacrol. However, the film containing chitosan had no significant effect on the growth of the studied fungi.

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Chickpea wilt caused by Fusarium oxysporum f. sp. ciceris is one of the major yield-limiting factors in chickpea, particularly in west and northwest of Iran. Simple Sequence Repeats (SSR) were used to determine genetic structure of Fusarium oxysporum f. sp. ciceris populations from three infected areas located in west and northwest provinces of Iran during 2016-2017. A set of six microsatellite primer pairs revealed 35 alleles in each locus with an average of 5.83 per locus. The PIC value varied from 0.20 (FOAG11) to 0.39 (FODF7) with an average of 0.27 per locus. The average number of effective alleles (N_e), Number of private alleles (N_a), allelic variability per locus (H), Shannon's Information Index (I) and percentage of Polymorphic Loci (%PL) in three populations were 1.33, 1.97, 0.2208, 0.357, and 74.29, respectively. The average genetic distance was calculated among the three populations. Nei’s pair-wise genetic distances between the populations varied from 0.0202 to 0.98. The total gene diversity (H_t) and gene diversities between subpopulations (H_s) were estimated to be 0.2208 and 0.2079, respectively. Gene diversity attributable to differentiation among populations (G_st) was 0.0585, while gene flow (N_m) was 8.0412. The AMOVA of genetic variation in Fusarium oxysporum f. sp. ciceris populations revealed that 5% of the variance occurred among populations and 95% within populations. PhiPT value was 0.054. The lowest genetic distance was found between Kurdistan and West Azerbaijan with Lorestan populations, while the highest genetic distance was observed between Lorestan and Kermanshah populations.