Biological control of Sclerotinia sclerotiorum (oilseed rape isolate) by an effective antagonist Streptomyces

Sclerotinia sclerotiorum (Lib) De Bary, the causal agent of stem rot of oilseed rape, is one of the most important phytopathogens. In order to find appropriate biocontrol agents, antagonistic and especially chitinolytical activities of 110 soil actinomycetes were examined. Among assayed isolates, Streptomyces sp. isolate 422 significantly reduced (P ≤ 0.01) the incidence of disease. Biological and physiological analysis of this isolate shown that, its active metabolite had polar nature, long shelf life and fungicidal activity features. Moreover, a partial chitinase (600 bp) gene was cloned and sequenced. This study has tried to introduce an effective biocontrol agent against S. sclerotiorum with a broad spectrum of antagonistic activity against phytopathogens.Key words: Biocontrol, Brassica napus L. ssp. Oleifera, Sclerotinia sclerotiorum, streptomycetes

Identifying the Dimensions and Components of Knowledge-based Decisionmaking and Presenting an Effective Model

The objective of this study was to identify the dimensions and components of knowledge-based decision-making and to present an effective model. The statistical population of the present study consists of two groups. The first group consists of experts who are familiar with knowledge-based decision-making theories that their number is unlimited and scattered across the country. They were selected purposefully and their opinions were applied in this study in the formulating and designing of the model. The second group consists of top-level, low-level, and middle-level managers of the Iranian National Tax Administration (n=2115), who are working in the tax affairs of Iran’s provinces and cities. According to the Cochran formula, 325 of them were selected as samples. The methodology of this study was descriptive-survey and knowledge-based decision-making. A questionnaire with a validity of 93.8 and reliability of 94.6% was used to collect the data. Structural equation modeling through LISREL 8.8 version software was used to analyze the data. Based on the results, the power of the relationship between the dimensions and components of knowledge-based decision-making (performance factors, behavioral factors, attitudinal factors, and structural factors) in the Iranian National Tax Administration was at a desirable level. The t-test statistic was also larger than the critical t-value of 1.96 at a 5% error level and showed a significant correlation. Based on the fitted models, it can be stated that the knowledge-based decisionmaking dimensions and components of the Iranian National Tax Administration have a relationship with each other and this relationship is direct

Forage Quality of Cow Pea (Vigna sinensis) Intercropped with Corn (Zea mays) as Affected by Nutrient Uptake and Light Interception

An experiment was carried out in 2003 to investigate the effect of intercropping on light interception, nutrient uptake and forage quality of cow pea. A randomized complete block design (RCB) with three replications was employed to compare the treatments, including cow pea sole crop (Cp), corn sole crop (C), alternate-row intercropping (M1), within-row intercropping (M2) and mixed intercropping (M3). The intercrop composition was based on replacement design, where one corn was replaced by three cow pea plants. The results indicated that PAR (photosyntheticaly active radiation) interception and nutrient uptake were improved by intercropping. Cow pea was more competitive than corn in absorbing divalent cations (Ca and Mg) for its high root cation exchange capacity. However, corn was more competitive than cow pea for phosphorus and potassium. Forage quality of cow pea in terms of crude protein was decreased in intercropping compared to its sole crop. It was related to reduction of biological nitrogen fixation induced by low PAR and phosphorus availability for cow pea in intercropping

Biocontrol of Rhizoctonia solani damping-off and promotion of tomato plant growth by endophytic actinomycetes isolated from native plants of Algerian Sahara

Thirty-four endophytic actinomycetes were isolated from the roots of native plants of the Algerian Sahara. Morphological and chemical studies showed that twenty-nine isolates belonged to the Streptomycesgenus and five were non-Streptomyces. All isolates were screened for their in vitro antifungal activityagainst Rhizoctonia solani. The six that had the greatest pathogen inhibitory capacities were subsequentlytested for their in vivo biocontrol potential on R. solani damping-off in sterilized and non-sterilized soils,and for their plant-growth promoting activities on tomato seedlings. In both soils, coating tomato seedswith antagonistic isolates significantly reduced (P < 0.05) the severity of damping-off of tomato seedlings.Among the isolates tested, the strains CA-2 and AA-2 exhibited the same disease incidence reduction asthioperoxydicarbonic diamide, tetramethylthiram (TMTD) and no significant differences (P < 0.05) wereobserved. Furthermore, they resulted in a significant increase in the seedling fresh weight, the seedling length and the root length of the seed-treated seedlings compared to the control. The taxonomic positionbased on 16S rDNA sequence analysis and phylogenetic studies indicated that the strains CA-2 AA-2were related to Streptomyces mutabilis NBRC 12800ᵀ(100% of similarity) and Streptomyces cyaneofuscatus JCM 4364ᵀ(100% of similarity), respectively

Identifying the Dimensions and Sustainable Supply Chain Operations for Knowledge-Based Decision Making in Iran’s Tax Affairs Organization

Abstract—This research was conducted by the aim of Identifying the dimensions and sustainable supply chain operations for knowledge-based decision making in the Iran tax affairs organization. From the point of purpose, this study is a fundamental research which is implemented by qualitative research. There is two main part in this study: the first one is about the background and theoretical basics which is related to the dimensions and components of knowledge-based decision making; the second part is a qualitative research that is implemented in a grounded theory methodology. This research’s population concludes experts of tax affairs organization in Iran. That experts has been chosen which have required qualifications and information by the use of purposive sampling method. The process of choosing these experts has continued until reaching the theoretical saturation which ended in 50 interviews. Open, axial and selective coding have been conducted respectively for analyzing the gathered data from interviews. The triangulation and control methods have implemented for confirmation and enhancement of the reliability of findings and interview transcripts. Based on a partial least squares approach, the confirmatory factor analysis method has also conducted for the estimate of indices. Respectively, the confirmatory factor analysis, Path analysis, and Bootstrapping have done in the frame of this approach. Findings of this study show that components of knowledge-based decision making are: 1- performance factor, 2- behavioral factor and 3- attitude factor

In vitro and in vivo antifungal properties of silver nanoparticles against Rhizoctonia solani, a common agent of rice sheath blight disease

Sheath blight disease in rice has caused major crop losses worldwide. Managing the causal agent of disease Rhizoctonia solani Kühn is difficult because of its broad host range and formation of sclerotia which can survive in harsh environmental conditions; therefore developing innovative disease management methods without application of hazardous chemicals has been considered as the main concern to maintain sustainable agriculture. This presented research has revealed the negative impact of Silver nanoparticles (SNPs) on R. solani and disease progress both in vitro and in vivo. The adverse effects of the SNPs on R. solani are significantly dependent on the quantity of SNPs, sprayed at different concentrations in vitro. The highest inhibition level against sclerotia formation and mycelia growth are 92 and 85%, respectively, at a SNPs concentration of 50 ppm. In vivo glasshouse experiments also showed that SNPs at the same concentration favorably affects both the fresh and dry weight of rice plants with a remarkable suppressive effect on the lesion development in leaves