27 research outputs found

    Study of clonal variation of 'Bidaneh Ghermez' grapevine cultivar in Iran

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    ArticleGrapevine (Vitis vinifera L.) is a well - known plant including different cultivars and clones. In spite of the extensive works at the cultivar level, identification and determination of clonal genetic variation has remained as a challenge. To assess the genetic variation between clones of grapevine cv. 'Bidaneh Ghermez', 20 selected clones were analyzed for cluster weight (CW), cluster length (CL), cluster width (CWI), berry weight (BW), berry length (BL), berry width (BWI) and total soluble solids (TSS) in randomized complete block design with three replications. Analysis of variance reveale d considerable genetic variation for all measured traits (except cluster width) among clones. Cluster analysis, discriminant function analysis and principal component analysis (PCA) showed same results and all clones assigned in 2 groups. First group was including 9 clones and second group was including 11 clones. Overall, our results indicated C7, C10, C12 and C14 clones were best clones and have potential to introduce promising clones for stablishing new vineyard with high yield

    Composite slab numerical strength test method under partial connection approach

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    The present uneconomic strength determination approach for profiled composite slab (PCS) constitutes a serious challenge that contributed significantly to design conservatism. This study seeks to address this challenge by developing and a subsequent experimental validation of a numerical strength determination function for PCS through implementing a rational-based approach. Hence, a procedural algorithm lead to the development of PCS determination function using longitudinal shear estimation method by considering section slenderness and deck characteristics. The strength test performance between the developed scheme and the experiment-based test results indicates high similarity, demonstrating the viability of the proposed strength determination methodology developed

    Stressed out symbiotes:hypotheses for the influence of abiotic stress on arbuscular mycorrhizal fungi

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    Abiotic stress is a widespread threat to both plant and soil communities. Arbuscular mycorrhizal (AM) fungi can alleviate effects of abiotic stress by improving host plant stress tolerance, but the direct effects of abiotic stress on AM fungi are less well understood. We propose two hypotheses predicting how AM fungi will respond to abiotic stress. The stress exclusion hypothesis predicts that AM fungal abundance and diversity will decrease with persistent abiotic stress. The mycorrhizal stress adaptation hypothesis predicts that AM fungi will evolve in response to abiotic stress to maintain their fitness. We conclude that abiotic stress can have effects on AM fungi independent of the effects on the host plant. AM fungal communities will change in composition in response to abiotic stress, which may mean the loss of important individual species. This could alter feedbacks to the plant community and beyond. AM fungi will adapt to abiotic stress independent of their host plant. The adaptation of AM fungi to abiotic stress should allow the maintenance of the plant-AM fungal mutualism in the face of changing climates. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00442-016-3673-7) contains supplementary material, which is available to authorized users

    Long-term deformations in continuous composite slabs

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    Evaluation of Different Genotypes of Sesame in Terms of Stress Sensitivity and Tolerance Indices in Water Deficit Conditions

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    To compare tolerance and sensitivity indices of sesame genotypes to water stress in Ahvaz (south-west of Iran) conditions, an experiment was conducted in Research Farm of Agricultural Sciences and Natural Resources University of Khuzestan, south-west of Iran, in summer 2018. The experimental design was split plot based on a randomized complete block design with four replicates. Experimental factors were three levels of irrigation (I1; fully irrigated, I2: changing altered irrigated and I3: fixed altered irrigated) in main plots and six sesame genotypes in subplots. The yield of studied genotypes showed a significant difference in different levels of irrigation. Genotype Shushtar produced the highest grain and oil yield and showed good performance in both normal and low irrigation conditions. The examined genotypes had significant differences in terms of Stress Sensitivity index (SSI), Tolerance Index (TI), Productivity Mean (PM), Harmonic Mean (HM), Yield Stability Index (YSI), Geometric Productivity Mean (GPM), Stress Tolerance Index (STI), Stress Damage Index (SDI), Modified Stress Tolerance for appropriate conditions (MSTI1), Modified Stress Tolerance for non-appropriate conditions (MSTI2), and Yield Reduction Index (YRI).  In general, the best indicator for evaluation of tolerance and susceptibility of sesame genotypes was stress tolerance index (STI). The most tolerant and sensitive genotypes were Shushtar and Halil genotypes, respectively

    Evaluation of Shrinkage-Induced Deflections of Composite Slabs with a Simplified Design Approach and a Hygro-Thermo-Chemical-Mechanical Model

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    Composite steel-concrete construction is widely used throughout the world for building and bridge applications. This paper focuses on the service behaviour of composite and post-tensioned composite floor slabs and how these are influenced by shrinkage effects. Research carried out in recent years has highlighted the occurrence of a non-uniform shrinkage profile that occurs through the thickness of a composite slab due to the inability of the concrete to dry from its underside because of the presence of the profiled steel sheeting. Two approaches are considered in this paper for the evaluation of the non-uniform shrinkage profile, one based on a simplified approach and one relying on a hygro-thermo-chemical-mechanical model. The deflection predictions produced by the non-uniform shrinkage profiles (obtained with the two approaches) are then calculated with a design procedure available in the literature. In the first part of the paper, the main factors influencing the composite shrinkage response are introduced, followed by the main features of the design model used for the deflection predictions and of the two approaches presented for the evaluation of the non-uniform shrinkage profiles. The adequacy of the two approaches is then evaluated by comparing the calculated long-term deflections with those measured experimentally from long-term tests carried out on selected post-tensioned composite slab samples that have been reported in the literature
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