208 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

    Toxicity and side effects of three insecticides on adult Chrysoperla carnea (Neu.: Chrysopidae) under laboratory conditions

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    Green lacewing, Chrysoperla carnea (Stephens), is an important predator of arthropod pests such as aphids, psyllids, thrips and whiteflies. Toxicity of endosulfan, imidacloprid and indoxacarb was assessed on male and female C. carnea in the laboratory. Contact bioassays were carried out in glass Petri dishes. The LC50 values for indoxacarb, imidacloprid and endosulfan were 0.011, 0.053, and 0.343 g AI/L for males, and 0.019, 0.098 and 0.398 g AI/L for females, respectively. Males were more sensitive than females to all three insecticides. To assess the sublethal effects, using IOBC (International Organization for Biological Control) method, adults were treated with LC25 of each insecticide. Analysis of variance did not show significant differences among treatments regarding the developmental time of the first, second and third instars, pupae and sex ratio. Differences between treatments and control were significant regarding pre-oviposition, oviposition and post-oviposition periods, fecundity, fertility, longevity of male and female. Mean longevity for control, imidacloprid, endosulfan and indoxacarb were 30 ± 2.3, 24.3 ± 3.3, 21.3 ± 2.4 and 19.7 ± 1.4 days for males, and 36.9 ± 2.5, 31.8 ± 2.9, 27.7 ± 1.7 and 26.7 ± 2.6 days for females, respectively. The highest and the lowest rates of fecundity were 540 ± 49 and 206 ± 42 in control and indoxacarb, respectively. Based on the IOBC classification method, imidacloprid, endosulfan and indoxacarb were slightly harmful (%30 < Total Effect Index < %79) against adults. The adult stage was very sensitive to indoxacarb, imidacloprid and endosulfan. Hence, these insecticides should not be applied when the density of adults is high in the field

    The Viable but Non-culturable State in Xanthomonas citri subsp. citri is a Reversible State Induced by Low Nutrient Availability and Copper Stress Conditions

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    Xcc (Xanthomonas citri subsp. citri) causes citrus bacterial canker, a leaf, stem and fruit spotting disease that affects most commercial citrus species and cultivars. Copper compounds, widely used for management of this pathogen, have been reported as inducers of a VBNC (viable but non-culturable state) in plant pathogenic bacteria. VBNC may be considered as a state preceding bacterial death or as a survival mechanism under adverse conditions. Several experiments were performed to characterize the reversibility and persistence of the VBNC state in Xcc. VBNC was induced in low nutrient medium or with amendment of copper at concentrations used for field disease control. The VBNC condition was demonstrated to persist up to 150 days after copper treatment and was reversed after the addition of culture media without copper or amendment with citrus leaf extract. Xcc viability was evaluated by recovery of colonies on culture media, confirmed by membrane integrity, respiratory activity and by real-time RT-PCR targeting a sequence from the gumD gene. Besides, the colonies recovered were pathogenic on citrus leaves. These results confirm that the VBNC state in Xcc is inducible and reversible and therefore may occur in the phyllosphere when Xcc is under copper stress or starvation

    Lethal and sublethal effects of dinotefuran and thiamethoxam on the population growth parameters of the green lacewing, Chrysoperla carnea (Neu.: Chrysopidae), under laboratory conditions

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    The green lacewing, Chrysoperla carnea (Stephens), is a common natural enemy of various agricultural pestsand widely used as a biocontrol agent in integrated pest management (IPM) programs. The lethal and sublethal effects of the insecticides dinotefuran and thiamethoxam on the first instar larvae of C. carnea was assessed in the laboratory conditions at 25 ± 1°C, 60 ± 5% RH and a photoperiod of 16: 8 (L: D). The LC50 values for dinotefuran and thiamethoxam were 19.382 and 9.880 mg ai/l, respectively, that showed the high toxicity of thiamethoxam on the first instar larvae of C. carnea. To assess the sublethal effects, the first instar larvae were treated with the LC30 for dinotefuran and thiamethoxam at 3.532 and 1.692 mg ai/l, respectively. The estimated rm values in the control, dinotefuran and thiamethoxam were 0.185, 0.186 and 0.143 day-1, respectively. Finite rate of increase (λ) in the control, dinotefuran and thiamethoxam were 1.204, 1.204 and 1.154 day-1. Generation time and doubling time values in the control, dinotefuran and thiamethoxam were 30.77, 30.46 and 35.14 as well as 3.73, 3.72 and 4.82 days, respectively. The gross and net reproductive rates in the control, dinotefuran and thiamethoxam were 459.89, 439.08 and 309.42, and also 298.01, 278.45 and 155.03 (female/female/generation), respectively. Dinotefuran caused no significant adverse effects on the population growth parameters of C. carnea. If similar results are obtained for dinotefuran in the field, it might be an insecticide with low toxicity to C. carnea by using the reduced doses of the insecticide in IPM context. Studies under the laboratory conditions can help us to select some insecticides for additional studies under more natural conditions and for application of suitable insecticides along with natural enemies in pest management

    Toolkit for exploring ethical aspects of digital social and affective touch interactions

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    In this hands-on demonstration, people are invited to use a newly developed toolkit to scrutinize their attitude and preferences towards digital social and affective touch interactions

    Purification of immature neuronal cells from neural stem cell progeny

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    Large-scale proliferation and multi-lineage differentiation capabilities make neural stem cells (NSCs) a promising renewable source of cells for therapeutic applications. However, the practical application for neuronal cell replacement is limited by heterogeneity of NSC progeny, relatively low yield of neurons, predominance of astrocytes, poor survival of donor cells following transplantation and the potential for uncontrolled proliferation of precursor cells. To address these impediments, we have developed a method for the generation of highly enriched immature neurons from murine NSC progeny. Adaptation of the standard differentiation procedure in concert with flow cytometry selection, using scattered light and positive fluorescent light selection based on cell surface antibody binding, provided a near pure (97%) immature neuron population. Using the purified neurons, we screened a panel of growth factors and found that bone morphogenetic protein-4 (BMP-4) demonstrated a strong survival effect on the cells in vitro, and enhanced their functional maturity. This effect was maintained following transplantation into the adult mouse striatum where we observed a 2-fold increase in the survival of the implanted cells and a 3-fold increase in NeuN expression. Additionally, based on the neural-colony forming cell assay (N-CFCA), we noted a 64 fold reduction of the bona fide NSC frequency in neuronal cell population and that implanted donor cells showed no signs of excessive or uncontrolled proliferation. The ability to provide defined neural cell populations from renewable sources such as NSC may find application for cell replacement therapies in the central nervous system

    Lethal and sublethal effects of endosulfan, imidacloprid and indoxacarb on first instar larvae of Chrysoperla carnea (Neu.: Chrysopidae) under laboratory conditions

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    The common green lacewing is an important natural enemy used for pest control in greenhouses. It is also very common in many agricultural systems. Hence, studying lethal and sublethal effects of insecticides on this predator would be useful. Toxicity of endosulfan, imidacloprid and indoxacarb was assessed on 1st instar larvae of Chrysoperla carnea (Stephens) in laboratory. Residual bioassays were carried out in glass Petri dishes. The LC50 values, for endosulfan, imidacloprid and indoxacarb were estimated 251, 24.6 and 133 mg ai/l, respectively. Imidacloprid was the most toxic among insecticides tested. To assess the sublethal effects, the 1st instars were treated with LC25 of each insecticide. Thereafter, these effects were studied using fertility life table experiments. The analysis of variance revealed significant difference between treatments and control with respect to developmental time of the 1st instar larvae. However, no significant difference was observed among endosulfan, imidacloprid and indoxacarb treatments considering the larval developmental time. Differences between treatments and control were not significant for the developmental time of the 2nd and 3rd instars, pupae, sex ratio, adult longevity, and adult fertility. The results showed that only net reproduction rate (R0) was significantly affected by treatments. The gross reproductive rate (GRR), intrinsic rate of increase (rm), doubling time (DT), mean generation time (T) and finite rate of increase (λ) were not affected. The highest and the lowest amounts of rm were 0.178 and 0.169 in control and indoxacarb, respectively. Imidacloprid was the most toxic of the insecticides tested on the 1st instar followed by indoxacarb and endosulfan. If results similar to laboratory findings are obtained in field conditions, these insecticides might be appropriate candidates for IPM programs

    Effects of imidacloprid, indoxacarb and endosulfan on egg, third-instar larva and pupa of green lacewing Chrysoperla carnea (Neu.: Chrysopidae)

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    The common green lacewing is a known biocontrol agent because of its wide geographical distribution, high compatibility with different agricultural systems, high searching ability and ease of rearing. Adults and larvae were reared on artificial diet and eggs of Anagasta kuehniella (Zell.) respectively. The toxicity of insecticides was assessed on eggs (dipping method), third-instar larvae (contact method), and pupae (topical application) of Chrysoperla carnea Stephens. In order to study the sublethal effects, the third-instar larvae were treated with recommended field rate of each insecticide. The effects of the insecticides were assessed using demographic toxicology methods. Rearing conditions were 26 ± 2ºC, 60 ± 10% relative humidity and a photoperiod of 16: 8 h (L: D). The results revealed that the insecticides did not affect eggs even at doses higher than recommended field rates. The LD50 values, of endosulfan, imidacloprid and indoxacarb for pupal stage were estimated to be 144, 33, and 21 µg ai/insect respectively. Since the insecticides did not affect the third-instar larvae at the recommended field rate, the LC50 was not estimated for this stage. The results showed that, only net reproduction rate (R0) was significantly affected by treatments. The highest and lowest amounts of rm were 0.176 and 0.152 for control and indoxacarb treatmnets respectively. Based on both acute toxicity and demographic toxicology methods, the rate of toxicity of the tested insecticides was as follows: indoxacarb > endosulfan > imidacloprid
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