Abstract: ABSTRACT Neotropical Annonaceae-derived bioinsecticides have shown promising control of insect pest species. In order to develop an alternative tool for control Zaprionus indianus (Gupta, 1970), an important invasive pest of Brazilian orchards, this study investigated the insecticidal activity of a formulation prepared from ethanolic seed extract of different Annona species (Annona mucosa Jacq., Annona muricata L., and Annona sylvatica A. St.-Hil.) at discriminatory concentration of 2000 mg L-1 in comparison with a limonoid-based bioinsecticide and a synthetic insecticide (spinetoram) as positive controls. In an ingestion and topical application bioassay, the formulation based on A. mucosa caused more than 95% mortality, which was equivalent to the mortality caused by the synthetic insecticide spinetoram. In a free-choice bioassay, A. mucosa (83%), bioinsecticide (88%) and synthetic insecticide (98%) produced a significant reduction in the number of eggs per fruit. In addition, formulations based on A. mucosa, A. sylvatica, A. muricata and bioinsecticide resulted in a 50% reduction in egg viability. In the field, A. mucosa and bioinsecticide negatively influenced the infestation by Z. indianus in figs, producing a significant reduction in the number of larvae per fruit (3.6 and 2.29 larvae per fruit, respectively) in relation to the control treatment (11 larvae per fruit). However, they were significantly inferior to the synthetic insecticide (0.71 larvae per fruit). Thus, A. mucosa, bioinsecticide and spinetoram have the potential to be used in the framework of Z. indianus management.
Abstract: ABSTRACT The specification of the most convenient cultivars based on multiple trait indices is a new approach in durum wheat (Triticum durum Desf.) adaptation and stability studies. This approach helps to define the best cultivar based on multiple traits and multiple locations because cultivars are affected by unpredictable climatic conditions. Some traits (ears per square meter, spike length, number of grains per spike, spike yield, and leaf chlorophyll content among others) can be produced for primary breeding purposes because they are influenced by environmental factors and indirectly affect grain yield and quality. Therefore, in the present study, the new genotype × yield trait (GYT) biplot approach was used to identify the best cultivar among 10 durum wheat cultivars based on multiple environments (8) and multiple traits (18). Cultivar ranking was examined by a superiority index that combined yield and other target traits with the GYT biplot. The general adaptability of each cultivar in terms of all the traits indicated differences based on environment means, and significant differences were found between varieties for the GYT biplot. In the GYT biplot, yield-trait combinations clearly indicated the most stable cultivars, whereas in the genotype × trait (GT) biplot, the best cultivars were not defined for all traits. ‘Sariçanak’ was ranked as the best combination of physio-morphological traits with grain yield, ‘Zühre’ was the best for more quality traits, and ‘Güneyyildizi’ was the best for both physio-morphological and quality traits in the GYT biplot. The GYT biplot combines traits with yield and can help the visual identification of the best cultivars; it is better than the GT biplot method.
Abstract: ABSTRACT In order to optimize the lettuce (Lactuca sativa L.) production in greenhouses and to evaluate how a usage of mulching and covering plants with woven agrotextile affects its yields, N content, nitrate, Zn and vitamin C in lettuce leaves, a 2-yr experiment was established. In the experiments, black and white plastic foils were used for mulching before planting, and woven agrotextile for plant covering after planting. The effect of each, as well as combination of them, on lettuce growth and productivity was evaluated. The experiment involved six treatments: control (without mulch), polyethylene black plastic mulch, polyethylene white plastic mulch, polyethylene black plastic mulch and woven agrotextile, polyethylene white plastic mulch and woven agrotextile, and woven agrotextile. In the first growing season the yield was 23% higher when polyethylene black plastic mulch was used compared to the control. In the second growing season the yield was 29% higher when polyethylene black plastic mulch was used compared to the control. Nitrogen content decreased 9% when the woven agrotextile was used compared to the control. Polyethylene black plastic mulch and polyethylene black plastic mulch with agrotextile reduced Zn content compared to the control. Vitamin C content increased 21% when woven agrotextile was used compared to the control. The overall effect of mulching and covering plants with woven agrotextile showed positive effect on lettuce production. The results obtained could assist lettuce growers in selecting most effective production technologies in order to achieve highest yield and nutritional value in this crop.
Abstract: ABSTRACT Degradation and desertification are extremely significant environmental problems in arid and semi-arid grassland ecosystems. Long-term overgrazing is the most fundamental cause of grassland degradation. We investigated relationships between grazing intensity and bacterial communities in non-rhizospheric and rhizospheric soils in desert steppe, including 0-10, 10- 20 and 20-30 cm depth soils, as well as Stipa breviflora Griseb., Cleistogenes songorica (Roshev.) Ohwi, Artemisia frigida Willd. and plant community rhizospheric soils. This involved simulating grazing intensities in a long-term localization experiment, using a randomized block design. The effects of grazing on non-rhizospheric soil bacterial abundance were reflected in the 0-10 cm layer, increasing under light grazing and decreasing rapidly under moderate and heavy grazing, mainly related to Bacillus. Bacterial abundance in dominant plant rhizosphere responded differently. In A. frigida Willd. Rhizosphere, it decreased with increasing grazing intensity (a trend repeated in mixed rhizosphere). Bacterial abundance in S. breviflora and C. songorica rhizosphere increased under light and decreased under moderate and heavy grazing. Thus, changes in the dominant plant rhizospheric bacterial community did not significantly affect bacterial abundance in mixed rhizosphere. Changes in the rhizospheric bacterial abundance mainly resulted from levels of the dominant species, Streptomyces and Arthrobacter. There were significantly different results for bacterial community structure. Specifically, grazing had a nonsignificant and significant impact on bacterial community structures in non-rhizospheric (FPERMANOVA = 1.38, p = 0.199) and rhizospheric (FPERMANOVA = 2.03, p = 0.012) soil, respectively, varying significantly among plants (FPERMANOVA = 1.9, p = 0.022). In conclusion, bacterial communities in rhizosphere were mainly affected by plant species and were more sensitive to changing grazing intensity than in non-rhizospheric soil.
Abstract: ABSTRACT In experiments with selection of perennial plants, the initial performance is expected to be maintained throughout the productive life. The probability of repeating the agronomic response can be evaluated by the repeatability coefficient. The objective was to estimate repeatability coefficients of agronomic characteristics in Panicum maximum Jacq. using different methods and identify the best combinations between harvests according to the genotypic stabilization. Seventeen genotypes were evaluated in a randomized complete block design with three replicates. The coefficients of repeatability were estimated by the methods: ANOVA, structural analysis based on the mean of the correlation coefficients (SACOR), analysis of principal components based on the covariance matrix (PCCOV) and correlation matrix (PCCOR). In the genotypic stabilization, coefficients estimated by ANOVA and PCCOR were used. For total DM, repeatability coefficients ranged from 0.3500 to 0.4300 by the ANOVA and PCCOR methods, respectively. High repeatability coefficients were found for the characteristic leaf DM, while low coefficients were observed for leaf and stem percentages and leaf:stem ratio. For the genotypic stabilization of total DM and leaf:stem ratio, the best coefficients were observed for the combination of harvests 5 to 8. There are variations in the estimate of repeatability by different methods and the highest coefficients were those of the principal components based on the correlation and covariance matrices. For the genotypic stabilization, the best coefficients of repeatability and determination were observed for the harvests performed in the second rainy period.
Abstract: ABSTRACT The avocado red mite Oligonychus yothersi (McGregor) is the most important avocado (Persea americana Mill.) foliar pest in Chile, infesting ‘Hass’ avocado between mid-summer and late autumn. The post-embryonic development, survival, longevity and life table parameters of O. yothersi were evaluated on both young and mature ‘Hass’ avocado leaves at 25 ± 0.7 °C, 60 ± 5% relative humidity and 16:8 h photoperiod. The time for larvae, protonymphs and deutonymphs to develop was longer on young leaves than on mature leaves. The immature stage of O. yothersi was shorter (9.29 ± 0.22 d) on mature leaves than on young leaves (14.43 ± 0.28 d); O. yothersi also exhibited higher survival rates for larvae, protonymphs, and deutonymphs on mature leaves. The net reproductive rate (R0) 52.756 ± 1.749 individuals female-1; intrinsic rate of increase (rm) 0.241 ± 0.002 female female-1 d-1, and finite rate of increase (λ) 1.273 ± 0.002 female female-1 of O. yothersi were significantly higher on mature avocado leaves than on young leaves (R0 = 2.727 ± 0.271, rm = 0.049 ± 0.004, and λ = 1.051 ± 0.004). The time required to double the O. yothersi population was only 2.872 ± 0.002 d on mature leaves. Therefore, life table parameters of O. yothersi are negatively affected by young avocado leaves, suggesting that constitutive defenses present in young leaves could affect O. yothersi population parameters.
Abstract: ABSTRACT Andean blackberry (Rubus glaucus Benth.) is an important crop of the Andean region affected by Colletotrichum gloeosporioides. In Colombia, tolerant plant material has been detected, but it has not been completely characterized. The objective of this research was oriented to analyze de novo transcriptome assembly of R. glaucus, and the comparison of the assembly with different reference genomes to further complete differential expression analysis of R. glaucus tolerant to C. gloespoiorides attack. To achieve this, three groups were used: infected tolerant material, infected susceptible material, and a susceptible group without inoculation. The RNA-seq sequencing was achieved through Illumina Hi-seq 2000. De novo assembly (Trinity, CD-HIT, TopHat) and functional annotation of sequences were carried out, additionally, mapping with reference genomes belonging to Rosaceae families was conducted (Bowtie2, TopHat). Subsequently, the differential expression was quantified (Cuffdiff) and analyzed through EdgeR. Variant analysis was made using MISA and SAMtools. After editing and assembly, 43579 consensus sequences were obtained (N50 = 489 bp; GC = 44.6%), annotation detected 35824 and 35602 sequences in Nt (partially non-redundant nucleotide sequences) and Nr (non-redundant protein sequences) databases, respectively. The 85% of Nr sequences was linked to members of Rosaceae family, mainly strawberry (67.6%). A total of 3570 simple sequence repeat (SSR) markers and 38791 single nucleotide polymorphisms (SNP) were found. The transcriptome of tolerant plants exhibited less SNPs. Finally, differentially expressed genes were found, including RPM1, MAPKBP1, CKX2. This research represents a contribution for future understanding of R. glaucus transcriptome, since there is little information available, and it would help further tolerance-related analysis.
Abstract: ABSTRACT Echinochloa colona (L.) Link is one of the most troublesome weed species in rice (Oryza sativa L.) crops. Despite numerous cases of herbicide resistance in E. colona worldwide, in Colombia the reports are scarce and most of them dating from over two decades ago. To screen the resistance of E. colona to bispyribac-sodium, cyhalofop-butyl and quinclorac, in the Saldaña and Purificación counties, a survey was carried out in 23 rice fields, through a grid of 26 squares of 2.56 km2 each. Seedlings from 23 populations were treated with commercial formulations from these respective herbicides at their recommended (1x) dose and twice the dose (2x) under controlled conditions. Relative fresh weight and percent control were evaluated. Populations with relative fresh weight greater than 20% and control below 80%, were categorized as resistant. For statistical analysis, a mixed model was used with populations as a random effect. The distribution of resistance was evaluated by a spatial autocorrelation analysis. It was established that 91% of populations were resistant to bispyribac-sodium, 48% to cyhalofop-butyl and 43% to quinclorac. Sixty-five percent had multiple resistance to two herbicides and 22% to three herbicides. Resistance was randomly distributed, according to the results obtained from the mixed model that showed a homogeneous response of populations within fields and heterogeneous among fields. This indicates that management strategies at field level generate a local selection pressure that determines the evolution of the resistance independently in each field.
Abstract: ABSTRACT Sesamum indicum L. has the potential to be cultivated as a forage plant in hot and dry climate regions, and it can be used to increase the food security of a herd. The objective of this study was to evaluate growth, production, and chemical composition of S. indicum compared with conventional forages used for silage production. The experiment used a randomized complete block design with split-plots related to time and four replicates per treatment. The plots consisted of four treatments (Zea mays L., Helianthus annuus L., Pennisetum glaucum [L.] R. Br., and S. indicum), and the subplots were two evaluation periods (2014 and 2016 harvests). Dry forage biomass production differed among the species in the 2014 harvest with values of 25 530, 12 190, 9408, and 9250 kg ha-1 for Z. mays, S. indicum, H. annuus, and P. glaucum, respectively. Maize had a greater variation in forage production between the 2 yr, followed by S. indicum. There were higher dry matter (DM) contents (P < 0.0001) for Z. mays and S. indicum (404.5 and 251.7 g kg-1, respectively). Regarding crude protein, H. annuus and S. indicum had levels of 167.2 and 117.7 g kg-1, respectively. According to the results, it can be inferred that sesame, like millet, provides greater feeding security for ruminant herds in regions with irregular rainfall.
Abstract: ABSTRACT The chemical mechanisms involved in indirect plant-mediated interactions between insects and phytopathogenic fungi on the host plant are poorly understood. Fungus-induced changes in the volatile organic compound (VOC) contents of plants need to be elucidated to address this. Here, changes in VOCs in rose (Rosa chinensis Jacq.) leaves infected with rose powdery mildew (Podosphaera pannosa [Wallr.: Fr.[ de Bary) were studied. VOCs were collected from undamaged live leaves of healthy and infected intact rose plants by dynamic headspace adsorption and identified by GC-MS. VOCs were extracted using n-hexane, and 38 chemicals were found to be produced by P. pannosa. A total of 71 VOCs not produced by P. pannosa were produced to different degrees by infected and healthy plants, and 18 of these were produced only by infected plants. Principal component analysis of chromatographic data gave VOC profiles distinguishing between infected and healthy plants. Hexadecanol, octadecanol, tetradecanol, n-butyl hexadecanoate, and n-butyl stearate dominated the VOCs produced by infected plants. These chemicals can be used as markers for detecting mildew-infected rose plants even 4-7 d after infection before symptoms appear. Clear temporal changes in the concentrations of these five chemicals were found. The results improve our understanding of the chemical mechanisms involved in interactions between insects and phytopathogenic fungi.
Abstract: ABSTRACT Xanthogaleruca luteola (Coleoptera: Chrysomelidae) is an aggressive defoliating pest on elms (Ulmus sp.) worldwide. We evaluated the antifeedant and insecticidal effects of ethanolic and aqueous extracts from Melia azedarach L. green fruits and leaves of Peumus boldus Molina, on X. luteola third instar larvae, the most harmful stage. Five doses of the extracts were applied to fresh elm leaves to determine antifeedant effect evaluating consumed foliar area at 24 h. Insecticidal activity was assessed through daily mortality for 14 d. For each extract an antifeedant index, relative to respective control, and mean lethal concentrations (LC50) were calculated. We found a direct relationship between concentration and both antifeedant and insecticidal effects for all extracts. A dose of 6.1% w/v of ethanolic extract of M. azedarach green fruits significantly inhibited larvae feeding behavior by 91% with a LC50 1.49% at day 8. On the other hand, 3.4% w/v of ethanolic extract of P. boldus inhibited larvae feeding behavior by 81% and LC50 at day 8 was 0.92% w/v. All extracts showed insecticidal effect on X. luteola larvae, and the highest mortalities observed were 79% and 71% with ethanolic and aqueous extracts of P. boldus, respectively. Antifeedant and insecticidal effects observed with M. azedarach green fruits and P. boldus leaf extracts on X. luteola third instar larvae, support the development of botanical insecticides from both tree species in order to contribute to its integrated management.
Abstract: ABSTRACT Nitrogen fertilization combined with microelements is an effective way to provide nutrients to plants, which are essential for obtaining high-value crops. The aim of this study was to evaluate two N fertilizer rates (150 and 200 kg ha-1) and four Mn fertilizer rates (0.0, 0.5, 1.0, and 1.5 kg Mn ha-1) on the N, Mn, Zn, Cu, and Fe content and composition of fatty acids in winter wheat (Triticum aestivum L.) grain. An increase in the N fertilizer rate increased (12.7%) the Mn content and decreased (10%) the Cu content of wheat grain. Regardless of N fertilization, foliar application of Mn at 1.5 kg ha-1 contributed to the highest Zn (28.4 mg kg-1) and Fe (58.4 mg kg-1) content in the grain. In an analysis of lipid fractions, the highest value of the coefficient of variation was recorded for C18:0 (16.3%-low variation). Nitrogen and Mn fertilization were most strongly correlated with the Mn content of grain (r = 0.356, r = 0.391, respectively). The 200 kg N ha-1 treatments combined with 1.0 kg ha-1 Mn and 150 kg ha-1 N without Mn were correlated with the content of C:18:0, C18:1c11, C18:1c9, and monounsaturated fatty acids in the grain. The application of 200 kg ha-1 N with 1.5 kg ha-1 Mn was correlated with the Fe, Zn, and Mn content of the grain. The remaining fertilization treatments were correlated with the content of C18:3, C18:2, polyunsaturated fatty acids (PUFA), and the C18:2/C18:3 ratio in the grain. Results indicated that the application of 200 kg ha-1 N beneficially affected the PUFA content in the winter wheat grain and can therefore be used to obtain raw material with increased nutritional value. The human organism does not synthesize PUFA, so they must be taken with food (or supplements); winter wheat grain can be a good source because it contains more than 60% PUFA.
Abstract: ABSTRACT Agro-industrial by-products are a great option for ruminant feeding. Alternative feedstuffs in ruminant diets are important to increase diets and reduce production costs. The present study evaluated different levels of palm (Elaeis guineensis Jacq.) kernel cake inclusion in diets for feedlot-finished cull cows and their implications on the intake and digestibility of dry matter (DM) and nutrients, as well as animal performance. The experiment was carried out in Ribeirão do Largo, Bahía, Brazil. Thirty-six Holstein × Zebu crossbred cows were assigned to four treatments at the rate of nine cows per treatment. The animals were fed sugarcane bagasse (roughage 15%) and concentrate (85%). The treatments were no addition of palm kernel cake, 8%, 16%, or 24% palm kernel cake inclusion in the total DM diet. Palm kernel cake inclusion influenced DM and nutrient intakes, which responded quadratically. The digestibility of DM, crude protein, and neutral detergent fiber corrected for ash and protein showed a quadratic response and maximum digestibility at 1.67%, 5.24%, and 3.68% cake inclusion levels, respectively; values decreased thereafter. The total digestible nutrients decreased linearly based on cake inclusion levels. Treatments affected final body weight, mean daily gain, and feed conversion, which showed a quadratic response to increasing levels of the by-product in the diet and maximum values were at 11.98%, 13.07%, and 16.32% inclusion, respectively. Palm kernel cake is a viable alternative ingredient for animal biological efficiency. The 16% inclusion level in the total DM diet was the most appropriate for the finishing of cull cows in the feedlot.
Abstract: ABSTRACT Diaphorina citri Kuwayama (Hemiptera: Liviidae) is an invasive species in America and is the main vector of the pathogen associated with Huanglongbing, a deadly disease of citrus plants in the world. The management of such a problem includes the intensive use of insecticides to reduce vector populations and risk of pathogen transmission. As an alternative to synthetic insecticides to control D. citri, the present study determined the chemical composition of diverse plant essential oils and assessed the toxicity and repellency of oil extracts against D. citri. Their chemical composition and abundance were determined by gas chromatography coupled to mass spectrometry. Adults and nymphs were exposed to leaf citrus discs treated by spraying or immersion with different oil extract concentrations. Repellency was assessed by exposing adults to treated leaves in experimental arenas and determining the number of insects remaining on the leaf after different time periods compared with the control. The main oil compounds in the tested plants were anethole, verbenone, 4-ethyl-4-methyl-1-hexene, 4-allylanisole, and trans-tagetone. Oils from Rosmarinus officinalis L. and Schinus molle L. caused no repellent or insecticide effects on D. citri. In contrast, oil extracts from the Foeniculum vulgare Mill. and Tagetes species were toxic and/or repellent for both adults and nymphs. There was a positive relationship between toxicity and concentration. Oil extracts from Tagetes lucida, T. coronopifolia, and T. terniflora were repellent (> 92%) at 40 mg mL-1; this was correlated with the concentration and decreased over time. Essential oils extracts from the Tagetes species could represent a potential defense that could be integrated into the management of D. citri.
Abstract: ABSTRACT Small grain cereals in lower latitude areas usually mature under terminal drought conditions that affect their agronomic performance. An experiment was conducted to compare agronomic traits, grain yield, and protein content under control and terminal drought conditions of 15 two-row and 10 six-row barley (Hordeum vulgare L.) genotypes. The experiment was set up at two locations for two growing seasons (2011, 2012) and two treatments. One treatment was terminal drought (D) simulated by the mechanical removal of all leaf blades 7 d after the heading of each genotype, and a control (C) treatment in which plants were left intact. On average, defoliation caused a greater reduction in grain yield and protein content of the six-row genotypes (37.6% and 12.3%, respectively) than the two-row genotypes (28.8% and 7.1%, respectively). On the other hand, test weight of six-row genotypes showed better tolerance to terminal drought. According to the multivariate function analysis, the genotypes of both types of barley with a high test weight, a longer uppermost internode, and a longer grain filling period had high protein content under terminal drought stress. In contrast to six-row genotypes, it is possible to breed two-row genotypes that not only have high grain yield but also high protein content under both optimal and drought stress conditions.
Abstract: ABSTRACT Cyantraniliprole has a broader insecticidal spectrum than the previously developed diamides. Because cyantraniliprole also targets hemipteran pests, it could provide an alternative to neonicotinoids like imidacloprid. However, there is limited information concerning how its broad-spectrum activity affects biological control agents. Toxicity of cyantraniliprole and imidacloprid to green peach aphid (Myzus persicae [Sulzer, 1776]), cabbage aphid (Brevicoryne brassicae [Linnaeus, 1758]) and greenhouse whitefly (Trialeurodes vaporariorum [Westwood, 1856]) nymphs was determined using both systemic and direct spray exposure. In addition, the direct spray activity of cyantraniliprole and imidacloprid on larvae of green lacewing, Chrysoperla defreitasi Brooks, 1994, was studied. Estimated LC50 values indicated that M. persicae, B. brassicae and T. vaporariorum were more susceptible to the systemic exposure to cyantraniliprole than to direct spray (0.148 vs. 24.284, 0.004 vs. 11.004, and 0.268 vs. 30.832 mg L-1, respectively). Similarly, susceptibility of M. persicae, B. brassicae and T. vaporariorum to imidacloprid was more pronounced when exposed systemically than through direct contact (0.018 vs. 1.149, 0.006 vs. 0.514, and 0.249 vs. 6.419 mg L-1, respectively). Hence, the population of B. brassicae was 40-fold more susceptible to cyantraniliprole than M. persicae when exposed to its systemic activity, and 2.2-fold more susceptible to cyantraniliprole’s direct spray activity than M. persicae. Interestingly, T. vaporariorum was less susceptible to the direct spray activities of cyantraniliprole compared to that of imidacloprid by 4.8-fold, but both insecticides were equally toxic for this species after systemic exposure. Crysoperla larvae were less susceptible to direct exposure to cyantranaliprole in comparison with imidacloprid (640.295 vs. 26.974 mg L-1). In comparison to imidacloprid, direct spray insecticidal activity of cyantraniliprole was less toxic to these hemipteran pests and to chrysoperla larvae. This suggests that the selectivity of cyantraniliprole towards C. defreitasi, as measured by direct spray only, could decline if its concentration is increased to target these hemipteran pests by foliar sprays.
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