Planta Daninha最新文献

{"title":"Germination of Solanum nigrum L. (Black Nightshade) in Response to Different Abiotic Factors","authors":"H. Dong, Y. Ma, H. Wu, W. Jiang, X. Ma","doi":"10.1590/s0100-83582020380100049","DOIUrl":"https://doi.org/10.1590/s0100-83582020380100049","url":null,"abstract":"ABSTRACT: Solanum nigrum L. (black nightshade), an annual to short-lived perennial weed, has become a problem weed in farming systems in central China. Laboratory and greenhouse experiments were conducted to examine the influence of various abiotic factors on seed germination of black nightshade to develop effective weed control programs. Seeds germinated at a range of constant temperatures from 15 to 30 oC, but no germination occurred at temperatures below 10 oC or above 35 oC. Seeds also germinated at alternating temperature regimes from 15/5 to 40/30 oC, with maximum germination (> 93.5%) at the alternating temperatures of 25/15 and 30/20 oC. Germination decreased as osmotic potential became more negative, and no germination was observed at ≤ -0.8 MPa. Moreover, germination was reduced by saline and alkaline stresses and no germination occurred at ≥ 200 mM NaCl or ≥ 150 mM NaHCO3 concentrations. Seed germination was not significantly affected by pH values from 5 to 10. Seedling emergence was significantly affected by burial depth with maximum emergence (93.1%) at 1 cm depth.","PeriodicalId":20102,"journal":{"name":"Planta Daninha","volume":"35 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67278924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nitrogen availability and glyphosate hormesis on white oat","authors":"Diecson R.O. Silva, Álvaro A. A. Silva, Bruna D. Novello, E. Rieder, Adalin C. M. Aguiar, Claudir J. Basso","doi":"10.1590/s0100-83582020380100071","DOIUrl":"https://doi.org/10.1590/s0100-83582020380100071","url":null,"abstract":"Background: The effect of low rates of glyphosate has been widely studied in several crops. Low nitrogen stress reduces carbohydrate synthesis and we hypothesize that hormesis from glyphosate occurs at low nitrogen availability. Objective: To evaluate the effects of glyphosate hormesis at different levels of nitrogen on the growth and yield of white oat. Methods: A two-factor factorial (2x7) was conducted in field testing at nitrogen levels (50 and 90 kg ha-1) and low rates of glyphosate rates (0 180 g a.e. ha-1). The glyphosate was applied at the second node already formed. The growth and yield were evaluated. Results: Plant height was not affected by the nitrogen levels. A low rate of glyphosate induced a plant height increase up of around 10%, but the stimulus was no maintained over in the time. Glyphosate hormesis had a greater effect on dry weight under low nitrogen than under high nitrogen conditions. The glyphosate provided a 43% increase in dry weight at a low nitrogen level when applied at rates consistent with a 4.1% field rate. Glyphosate hormesis increased the yield by approximately 30%, and the yield was higher yield under low nitrogen conditions. Conclusions: The plant height stimulus from low doses of glyphosate was not sustained over time. Glyphosate hormesis stimulus persisted and culminated in an increase in dry weight and grain yield. The hormesis effect on dry weight and yield is more pronounced under lower nitrogen availability.","PeriodicalId":20102,"journal":{"name":"Planta Daninha","volume":"35 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67279248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Weed control and selectivity herbicides pre emerging in garlic cultivars","authors":"N. Guerra, Renan Haramoto, J. Schmitt, Gabriel D. Costa, J. J. Schiessel, Antonio M. Oliveira Neto","doi":"10.1590/s0100-83582020380100074","DOIUrl":"https://doi.org/10.1590/s0100-83582020380100074","url":null,"abstract":"Santa Catarina State. Methods: Two experiments were carried out in the commercial garlic area with Ito and Chonan cultivars. Both experiments were conducted in randomized block design. The traits for Ito cultivar were without weed control, with weed control, with linuron (810 g ha -1 ), diuron (1,000 g ha -1 ), pendimethalin (1600 g ha -1 ), S-metolachlor (1200 g ha -1 ), oxyfluorfen (720 g ha -1 ) or flumioxazin (40 g ha -1 ). For the experiment with Chonan cultivar the treatment composed by oxadiazon (1000 g ha -1 ) was included. The analyzed variables were based on weed community control and phytotoxicity, stand, diameter of bulbs and productivity of garlic. Results: The infesting species of the experiment with the cultivar Ito were Stellaria media and Stachys arvensis , whereas for Chonan, only the first was found. The herbicides applied in pre-emergence were efficient in controlling these species until 45 days after application - DAA. The highest injuries at 45 DAA were caused by S-metolachlor, with 33% for Ito cultivar and 10% for Chonan. The best herbicides, taking into account weed control and productivity, were pendimethalin and S-metolachlor, for the Ito cultivar, and pendimethalin, oxyfluorfen, and flumioxazin for the Chonan cultivar. Conclusions: The pendimethalin stood out for presenting excellent weed control and being selective for","PeriodicalId":20102,"journal":{"name":"Planta Daninha","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67279334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rice root growth and development in competition with weedy rice","authors":"Carlos E. Schaedler, Célio U.M. Taborda, Francisco A.P. Goulart, Diego M. Chiapinotto, P. J. Pinho","doi":"10.1590/s0100-83582020380100086","DOIUrl":"https://doi.org/10.1590/s0100-83582020380100086","url":null,"abstract":"Background: Weedy rice belongs to the same taxon as irrigated rice (Oryza sativa L.), and is the main weed of the crop. However, it exhibits different traits that produce greater competitive capacity using solar radiation. In competition for light, plants invest in photoassimilates for the shoots and can reduce their root development. Objectives: The objective of this work is to evaluate the initial growth of weedy and cultivated rice roots in response to light competition. Methods: The experiment was conducted in a greenhouse (hydroponic system), using a completely randomized design, arranged in a 2x2x6 factorial scheme, with five replications. Factor A consisted of the weedy rice biotype Q35B and the rice cultivar IRGA 424; factor B of light competition conditions (presence or absence of 75 weedy rice plants); and factor C of assessment time. At 0, 7, 14, 21, 28 and 35 days after transplanting, samples were taken from each experimental unity to measure the root area, perimeter, length, number of tips, and root dry weight (RDW), and shoot dry weight (SDW). Results: Competition for light reduced the area, perimeter, length, number of root tips, reduced the RDW and the SDW of both, the weedy rice biotype and crop rice. However, regardless of the competitive condition, the weedy rice showed a higher area, perimeter, initial growth, number of tips, RDW and SDW than that of cultivated rice. Conclusion: Weedy rice exhibits greater competitive capacity using the resources beneath the soil.","PeriodicalId":20102,"journal":{"name":"Planta Daninha","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67280071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamics of diuron and sulfentrazone formulations in soils with different textures","authors":"Ana K. A. Matos, C. A. Carbonari, Ivana P. F.S. Brito, Giovanna L.G.C. Gomes, Maria L. B. Trindade, Edivaldo D. Velini","doi":"10.1590/s0100-83582020380100068","DOIUrl":"https://doi.org/10.1590/s0100-83582020380100068","url":null,"abstract":"Background: The use of commercial mix and tank mix with two or more herbicides is a widespread practice. However, despite its several possible benefits, little is known about its effect on the behavior of the molecules in the soil, which can increase or reduce the leaching potential of these molecules. Objective: This study evaluated the leaching potential of the herbicides diuron and sulfentrazone applied, using commercial mix and tank mix, in soils with different textures. Methods: The herbicides diuron (1,750 g ha-1) and sulfentrazone (875 g ha-1) were applied in three soils with different textures (clayey, medium, and sandy), using a commercial mix (Stone®) and a tank mix (Herburon 500 BR + Boral®). Subsequently, the treated soils were reconstituted in soil columns subjected to rainfall simulations with accumulated rainfall volumes of 40, 80, and 120 mm; the leached solutions were collected and analyzed by LC-MS/MS. Results: The results indicated a low descending movement of diuron in the three soils evaluated, when applied using commercial and tank mixes with sulfentrazone. Higher rainfall volumes (80 and 120 mm) were required to increase the diuron movement (≈20% of diuron applied). Sulfentrazone showed a high leaching potential in the soils, whereas the tank mix increased the leaching potential in sandy soil with the rainfall depths of 80 and 120 mm. Conclusions: The formulations did not affect the leaching potential of the herbicides in clayey and medium soil. However, the tank mix promoted greater leaching of the herbicides in the sandy soil when compared to the commercial mix.","PeriodicalId":20102,"journal":{"name":"Planta Daninha","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67279150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multivariate analysis using a discriminant method for evaluating the techniques of weed management in soybean crop","authors":"A. Bianchini, Pedro V.D. Moraes, Solon J. Longhi, Paulo F. Adami, Patricia Rossi, Vanderson V. Batista","doi":"10.1590/s0100-83582020380100077","DOIUrl":"https://doi.org/10.1590/s0100-83582020380100077","url":null,"abstract":"Background: The analysis of information generated from experiments involving different treatments, can be done by multivariate statistical analysis techniques, such as discriminant analysis, to analyze data obtained from predefined groups. Objective: Verify, through discriminant analysis, the differences among cover crop (Avena strigosa, Chenopodium quinoa, Cichorium intybus, and fallow land) treatments with respect to main crop soybean yield. Methods: For weed control, these cover crops were subjected to different management techniques, namely mowing, the application of glyphosate or the application of paraquat. The experimental design consisted of completely randomized blocks in a 4 × 3 × 2 factorial scheme, with four replications, consisting of the following factors: Factor A: (treatment) cover crops of A. strigosa, C. quinoa, C. intybus, and fallow land; Factor B: (management) plots were subdivided and treated with the application of paraquat or glyphosate, or the mowing of cover plants; Factor C: the plots were sub-subdivided and managed by one or two applications of a post-emergence herbicide. In order to evaluate the percentage of correct classifications of the different management techniques and treatments, a data matrix was elaborated for evaluation of variables relating to the soybean crop and the data were standardized by log log 10 log (n; 10). Multivariate analysis was performed using Fisher's linear discriminant method. Results: Discriminant analysis selected four variables with discriminatory power relating to the A. strigosa, C. quinoa, C. intybus and fallow, which contributed to 100% of the explained variance. Conclusions: Treatment with oats used as a cover crop provided higher soybean crop yield, whereas in terms of management, weed control using glyphosate provided the best results with all cover crops. SBCPD | Planta Daninha Bianchini A, et al. Multivariate analysis in soybean Planta Daninha 2020;38:e020210864 https://doi.org/10.1590/S0100-83582020380100077 2/8","PeriodicalId":20102,"journal":{"name":"Planta Daninha","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67279454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Off-season management with herbicides as an alternative to reduce weed infestation in paddy rice production systems","authors":"Antonio M. Oliveira Neto, N. Guerra, J. A. Noldin","doi":"10.1590/s0100-83582020380100082","DOIUrl":"https://doi.org/10.1590/s0100-83582020380100082","url":null,"abstract":"Background: Weed management is a challenge in paddy rice production, mainly due to the dispersal of a population resistant to herbicides. Objective: To assess the efficacy of chemical weed control in the offseason to reduce weedy rice and other species in water-seeded or drilled rice. Methods: Two experiments were carried out in a flat field to water-seeded or drilled rice, in randomized block design. The water-seeded system treatments were organized in a split-plot design. In the plot were evaluated two water management in the off-season (with or without continuous flooding), and in the subplot nine herbicides-treatments were evaluated (Check, clomazone at 0.72 and 1.08 kg a.i. ha-1, oxadiazon at 1.00 and 1.50 kg a.i. ha-1, oxyfluorfen at 0.312 and 0.48 kg a.i. ha-1, S-metolachlor at 1.44 kg a.i. ha-1, and flumioxazin a 0.075 kg a.i. ha-1). In the drilled rice experiment, the treatments were organized in a two-factor factorial. The factor A was nine herbicides treatments (the same herbicide and rates applied in water-seeded experiment) and the factor B was two application time (73 and 43 days before of rice-sowing). Results: Off-season management was efficient to reduce weedy rice infestation only on the paddy rice system using the pre-germinated seeds. In this assay, flumioxazin was an efficient alternative to giant arrowhead control, however the selectivity of this herbicide treatment needs to be studied. In dry-seeded system, herbicide sprayed in off-season reduced barnyardgrass infestation until the paddy rice sowing. Conclusions: The off-season management was efficient to reduce weedy rice and giant arrowhead infestation in water-seeded system, and barnyardgrass infestation in drill-seeded system.","PeriodicalId":20102,"journal":{"name":"Planta Daninha","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67279620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The addition of adjuvants on glyphosate enhances the control of aquatic plant Myriophyllum aquaticum (Vell.)","authors":"Wilson R. Cerveira Jr., Adilson F. Silva, João H.C. Cervoni, C. Cruz, Robinson A. Pitelli","doi":"10.1590/s0100-83582020380100090","DOIUrl":"https://doi.org/10.1590/s0100-83582020380100090","url":null,"abstract":"Background: Knowledge about the action of glyphosate alone and associated with adjuvants in the effectiveness to control aquatic plants is important in the decision-making on its use. Objective: This study aimed to evaluate the effectiveness of glyphosate and five adjuvants in the control of Myriophyllum aquaticum. Methods: Glyphosate (Rodeo®) at doses of 1.5, 3.5, 5.5, and 7.5 L ha-1 was sprayed alone and associated with Aterbane® BR, Veget’oil®, Dash® HC, Assist®, and Agral® (0.5% v v-1), in addition to the control, with a spray solution volume of 200 L ha-1. The effectiveness of control was evaluated using the scores of a visual scale at 3, 7, 15, 21, 30, 45, and 60 days after application (DAA), regrowth, and dry matter accumulation at 60 DAA. Results: The best effectiveness of control of the glyphosate alone was 85% at the dose of 7.5 L ha-1, increasing to 100% when associated with Aterbane® and Veget’oil®. The control reached 100% for all glyphosate doses associated with Dash®. Moreover, glyphosate at the dose of 7.5 L ha-1 associated with Assist® provided a 98% control, while glyphosate doses of 3.5, 5.5, and 7.5 L ha-1 associated with Agral® provided a 100% control. Glyphosate at doses of 5.5 and 7.5 L ha-1 associated with Dash® and Agral® was more effective in reducing the regrowth and dry biomass (100%). Thus, glyphosate + Dash® and Agral® promoted the highest control (above 95%), the lowest regrowth, and the highest reduction in the dry biomass of M. aquaticum. Conclusions: The addition of Aterbane® BR, Dash®, and Agral® to glyphosate improved the effectiveness of control of M. aquaticum and contributed to reducing the applied herbicide dose.","PeriodicalId":20102,"journal":{"name":"Planta Daninha","volume":"38 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67279771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Management and development of fleabane plants in central Brazil","authors":"N. M. Correia","doi":"10.1590/s0100-83582020380100084","DOIUrl":"https://doi.org/10.1590/s0100-83582020380100084","url":null,"abstract":"Background: Fleabane plants (Conyza spp.) resistant to glyphosate herbicide are found infesting areas in the Central-West and Southeast regions of Brazil, but its management is not a concerning problem for summer crops in these regions as in the South region of Brazil. Objective: To evaluate the management of adult fleabane plants at the summer soybean crop and off-season (autumn-winter), monitoring new emergences to assess the dynamics of plants from November 2018 to March 2020, and the residual effect of herbicides applied at the end of the rainy season in the Cerrado biome, in Brasília, DF, Brazil. Methods: Four field experiments were developed from November 06, 2018 to April 02, 2020; all under randomized block design, with four replications, in factorial or split-plot arrangement, with visual weed control evaluations (0% to 100%) and seedling counting. Results: The highest fleabane infestations in soybean crops were found before sowing, and were partially or fully controlled by pre-sowing chemical/management treatments, which did not interfere with the soybean seed yield. The fleabane biological cycle ended in NovemberDecember (1st year), and December-January (2nd year). Conclusions: The most significant fleabane emergence in the areas was found in February and March. The treatments with saflufenacil and glufosinate-ammonium, followed by 2,4-D, were the most efficient and fastest control of adult fleabane plants.","PeriodicalId":20102,"journal":{"name":"Planta Daninha","volume":"1 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67280058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic Dissimilarity in Conyza sumatrensis Revealed by Simple Sequence Repeat (SSR) Markers","authors":"T. Schneider, M. A. Rizzardi, S. Brammer, S. Scheffer-Basso, A. L. Nunes","doi":"10.1590/s0100-83582020380100018","DOIUrl":"https://doi.org/10.1590/s0100-83582020380100018","url":null,"abstract":"ABSTRACT: In view of the rapid evolution of Conyza sumatrensis populations resistant to glyphosate, it is necessary to understand the genetic diversity aimed to improve strategies for managing this weed. We investigated the genetic dissimilarity among 15 biotypes of C. sumatrensis from different geographic regions using microsatellite loci. The biotypes, were cultivated in a greenhouse to obtain vegetal material for DNA extraction. Nineteen microsatellite markers (SSR), were developed for C. sumatrensis biotypes. The genetic dissimilarity was estimated by the Jaccard coefficient (JC) and the biotypes grouped by the UPGMA method. The results demonstrated a high dissimilarity (JC = 7.14 to 82.62) of the analyzed material, with the biotypes forming five groups, being one group formed just by the susceptible biotype and in the others grouped by biotypes from distinct locations in the same group The high genetic diversity of C. sumatrensis indicates that the biotypes may show different responses to different management strategies, and that the mechanisms of resistance to herbicides and characteristics of evolution of populations due to adaptability may be some of the factors involved in the genetic variability of the species.","PeriodicalId":20102,"journal":{"name":"Planta Daninha","volume":"38 1","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67277801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}