Search

Made available in DSpace on 2019-10-03T18:19:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-08-01. Added 1 bitstream(s) on 2019-10-09T18:33:21Z : No. of bitstreams: 1 S0100-204X2018000800909.pdf: 458835 bytes, checksum: b4658d73c9c98102ddd084f2d5fb09ae (MD5) Universidade Federal do Parana The objective of this work was to evaluate the effect of winter cover crop species on the agronomic performance of soybean (Glycine max) cropped in succession, under a no-tillage system. The study was conducted during three crop seasons (2011/2012, 2012/2013, and 2013/2014), with the following cover crops: white oat (Avena sativa), black oat (Avena strigosa), ryegrass (Lolium multiflorum), vetch (Vicia sativa), forage radish (Raphanus sativus), the intercrop black oat + forage radish, and wheat (Triticum aestivum) as the standard management. Forage radish and the intercrop black oat + forage radish provided greater soil cover rates after 30 days of planting, as well as dry matter production in the three crop seasons. After 45 and 90 days from desiccation, however, white oat and ryegrass showed the highest soil cover rate. Black oat and the intercrop black oat + forage radish provided higher soybean yield than the standard management with wheat, in the 2012/2013 and 2013/2014 crop seasons. Winter cover crops can significantly affect soybean yield in succession, and black oat and the intercrop black oat + forage radish stand out for this purpose. Univ Estadual Paulista, Fac Ciencia Agron, Campus Botucatu,Ave Univ 3-780, BR-18610034 Botucatu, SP, Brazil Univ Fed Parana, Setor Palotina, Rua Pioneiro 2-153, BR-85950000 Palotina, PR, Brazil Univ Estadual Paulista, Fac Ciencia Agron, Campus Botucatu,Ave Univ 3-780, BR-18610034 Botucatu, SP, Brazil

Made available in DSpace on 2019-10-06T15:52:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01. Added 1 bitstream(s) on 2021-07-15T14:35:37Z : No. of bitstreams: 1 S0100-83582019000100238.pdf: 317328 bytes, checksum: 17b818586ee9c7b39a6af91680f80e6a (MD5) Horseweed (Conyza spp.) is a weed with a considerable presence and frequency throughout Brazilian crops, as well as presenting difficult chemical control. The objective of this study was to evaluate the efficiency of herbicide management, through single and sequential applications, in controlling Conyza spp., at two development stages with 4 to 6 leaves (3 to 5 cm) and 20 leaves (15-20 cm). The analyzed variables were: control percentage (7, 14, 21, and 28 days after application), dry matter content (28 days after application) and regrowth percentage (21 days after application). Data were submitted to analysis of variance at 5% probability and when there was a difference, the means were submitted to the Scott-Knott test. For Conyza spp. plants with a height between 3 and 5 cm and 4 to 6 leaves, the best treatments were T4, T8, T9, T10, T11, T12, T13, and T14, presenting a control percentage above 90%, 7 days after application. For Conyzaspp. plants with a plant development of 15 cm in height and 15 to 20 leaves, the highest control percentages and lowest regrowth percentages were with treatments T9, T13, and T14. UNESP Botucatu Universidade Federal do Paraná UNESP Botucatu

Phosphinothricin acetyltransferase ( pat) gene confers resistance to glufosinate by transforming this herbicide into N-acetyl-l-glufosinate (NAG). The pat gene was inserted in six maize hybrids (Herculex, Agrisure TL, Herculex Yieldgard, Leptra, Viptera 3, Power Core) as a selectable marker, and its expression was evaluated by qPCR in comparison with the maize glufosinate-susceptible cultivar VTPRO. In addition, the levels of NAG, glufosinate degradation, ammonia accumulation, electron transport rate (ETR), visual injury, and biomass were also investigated. The VTPRO, Herculex, Agrisure, and Viptera showed lower pat gene expression, and consequently lower NAG contents and glufosinate degradation, as well as reduced ETR and biomass accumulation. In contrast, greater ammonia accumulation and higher visual injury were observed. The ranking of pat gene expression was LeptraPower CoreHerculex Yieldgard ≫ HerculexAgrisure TL = Viptera 3VTPRO. This gene expression was proportional to the glufosinate resistance level observed in each maize hybrid.

Made available in DSpace on 2019-10-03T18:19:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01. Added 1 bitstream(s) on 2019-10-09T18:33:21Z : No. of bitstreams: 1 S0100-83582018000100306.pdf: 1030366 bytes, checksum: 0a20f2f4f94286c88fdd366df1b1a081 (MD5) This study aimed at evaluating the agronomic performance of Intacta RR2 soybean submitted to the application of glyphosate doses in post-emergence. For this, two experiments were conducted in two locations (Palotina and Marechal Candido Rondon - Parana state). Applications were carried out with increasing rates of glyphosate (0, 720, 1,440, 2,160, 2,880, 3,600, 4,320 g a.e. ha(-1)), constituting seven treatments with an experimental design in randomized blocks with four replications, totaling 28 plots for each location. The cultivar used for both experiments was Monsoy 6210 Intacta RR2 IPRO (TM). The analyzed variables were phytotoxicity at 3, 7,14, 21 and 28 DAA, A-B and total chlorophyll index, final height, number of pods, 100-seed weight, and yield. A regression analysis was used. There was a positive behavior of the linear regression for phytotoxicity and a negative one for final height, number of pods, A-B and total chlorophyll index, and yield in the city of Palotina. In Marechal Candido Rondon, there were adjustments of the positive linear regressions for phytotoxicity, and negative linear regressions for chlorophyll index, final height, number of pods and yield. Results show that the glyphosate increase from the dose 1,440 g a.e. ha(-1) in the studied cultivar damaged the agronomic performance of the culture. UNESP, Botucatu, SP, Brazil Univ Fed Parana, Palotina, PR, Brazil UNESP, Botucatu, SP, Brazil

Made available in DSpace on 2018-12-11T16:51:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-04-01 Universidade Federal do Paraná For optimum yield, it is necessary to incorporate a good weed control into the system. This study aimed to determine the effects of a post-emergent application of different herbicides (individually and combined) on corn presenting cp4-epsps and pat genes. Field studies were conducted on the corn hybrid 2B810 with the cp4-epsps and pat genes in the agricultural years 2012/13 and 2013/14 and included 8 treatments with isolated and combined application of glyphosate, glufosinate-ammonium, and atrazine. The variables evaluated were chlorophyll type a and b, total chlorophyll index, stem diameter, height of the cob insertion, prolificacy index, first height, second height, yield, and volume of 100 grains. The combination of all three herbicides hindered the yield of corn cultures. This practice therefore requires caution when applied to weed management. The combination of two herbicides did not affect the final height or yield and may be a useful method of weed management in future. São Paulo State University (Unesp) School of Agriculture Federal University of Paraná - Agronomy Department Luiz de Queiroz College of Agriculture University of São Paulo São Paulo State University (Unesp) School of Agriculture

The Roundup Ready (RR) soybean was developed for weed control with the use of glyphosate. Some herbicide combinations with glyphosate has been used in weed control and some effects of this practice may be undesirable in the agronomic performance of RR soybean. The present study evaluated the agronomic performance of RR2 intact soybean applied with associations between herbicides and glyphosate at post-emergence, in two experiments conducted in two municipalities in the state of Paraná, Palotina and Marechal Cândido Rondon. This experiment consisted of seven treatments in a randomized block design with four replications, totaling 28 plots for each municipality. The cultivar used in both experiments was Monsoy 6210 Intact RR2 IPROTM. The variables analyzed were: phytotoxicity at 3, 7, 14, 21 and 28 days after application, chlorophyll A, B and total chlorophyll, final height, number of pods, 100 seed weight and yield. Data were analyzed by analysis of variance and Tukey’s test at 5%. There were differences between treatments for phytotoxicity in both locations and differences in yield (Palotina) and final height (Marechal Cândido Rondon). From the data it is understood that some associations of certain herbicides such as lactofen, chlorimuron-ethyl in the glyphosate can potentiating effect cause phytotoxicity and even reduction in productivity. RESUMO: A soja Roundup Ready (RR) foi desenvolvida para controle de plantas daninhas com a utilização do herbicida glyphosate. Algumas associações de herbicidas com o glyphosate vêm sendo usadas no controle de plantas daninhas, e alguns efeitos dessa prática podem ser indesejados no desempenho agronômico da soja RR. O presente trabalho objetivou avaliar o desempenho agronômico da soja intacta RR2 submetida a associações de herbicidas com o glyphosate, em pós-emergência. Para isso, foram realizados dois experimentos em duas localidades (Palotina - PR e Marechal Cândido Rondon - PR). Esses experimentos contiveram sete tratamentos com delineamento em blocos ao acaso com quatro repetições. O cultivar utilizado em ambas as localidades foi o Monsoy 6210 Intacta RR2 IPROTM. As variáveis analisadas foram fitotoxicidade aos 3, 7, 14, 21 e 28 dias após aplicação, índice de clorofila A, B e total, altura final, número de vagens, massa de 100 sementes e produtividade. Foi feita a análise de variância e utilizado o teste de média de Tukey a 5%. Houve diferença entre os tratamentos para fitotoxicidade em ambas as localidades e diferença na produtividade (Palotina) e altura final (Marechal Cândido Rondon). A partir dos resultados, conclui-se que algumas associações de determinados herbicidas, como chlorimuron-ethyl e lactofen, na presença do glyphosate podem provocar efeito potencializador de fitotoxicidade e até mesmo na redução na produtividade.

In Brazil, there are several crops producing oil for biofuel production, such as canola, sunflower, peanut, cotton, castor bean, soybean, among others. There are parameters that indicate the energetic and economic viability for the production of biofuels, and that can be applied, for example, in transgenic soybeans. The present study aimed to evaluate the energetic viability of Intacta RR2 PROTM soybean for biofuel production.Experiments were conducted in the municipalities of Palotina and Marechal Cândido Rondon, both in the State of Parana. Energy balance calculations were carried out from the production system, estimating energy expenditure, including the agricultural and industrial stages. The inputs used were considered as input of energy, while grain production, as output of energy. The energy balance of soybean biofuel showed positive values in the treatments with lower doses up to the recommended doses, highlighting the treatment glyphosate at 720 g.e.a. per hectare, which reached a positive energy balance (1: 1.11) for both municipalities. However, the Intacta RR2 PRO TM soybean was sensitive to treatments with high doses of glyphosate, which impaired productivity and consequently generated low economic returns.

The planting of RR2 Intacta soybeans by farmers has been expanding strongly. However, some visual injuries have been noted after glyphosate application. The aim of this study was to evaluate the influence of glyphosate application on chlorophyll, photosynthesis and water use of four Intacta RR2 soybean cultivars. The experiment was conducted in a greenhouse, in a randomized block design with a 3 × 4 factorial scheme, consisting of three glyphosate rates and four soybean cultivars. The glyphosate formula used was isopropylamine salt + potassium salt. The parameters analyzed were phytotoxicity at 7, 14, 21 and 28 days after application, and total chlorophyll index at 0, 3, 7, 14, 21, 28, 35, 42 and 49 days after application. Furthermore, 40 days after application, the net CO2 assimilation rate (A), transpiration rate (E), stomatal conductance (G), and internal CO2 concentration (Ci) were evaluated as well. The water-use efficiency (WUE) and carboxylation efficiency were calculated. The data were submitted to analysis of variance and compared by the Tukey’s test (p ≤ 0.05), followed by regression analysis. The phytotoxicity influence could be seen until 21 days after application, in which Monsoy 6210 IPRO cultivar was the most injured. The increasing doses promoted a reduction of the chlorophyll level up to 35 days after application in Monsoy 6410 IPRO. The cultivars tested here showed similar chlorophyll index values. On the 3rd, 7th and 14th DAA (Fig. 5a–c), there was a significant linear decline in the chlorophyll index with rising glyphosate dose for all four cultivars. The chlorophyll index cultivars were not influenced by the doses on the 42nd and 49th DAA. There was no difference in water use and carboxylation efficiency. The parameters A, E and A/Ci showed a positive correlation as the doses increased, while Ci declined, in both cultivars. The application of glyphosate on these soybean cultivars causes different injuries according to the sensitivity. In general, RR2 soybeans have the ability to recover from visual intoxication injuries and reestablish the normal chlorophyll production and photosynthetic parameters after glyphosate application.

The benefits of glyphosate tolerant crops technology are well-known, and its acceptance by farmers is undeniable. However, results of recent research indicate that, in some situations, glyphosate applied to herbicide-tolerant soybean crops may have phytotoxic effects affecting nutritional balance, photosynthesis and others biochemical process in plants. Despite the increasing information available on this subject, there are still scientific and technical issues that need to be clarified. Therefore, the present study aimed to assess the impact of applying different rates, management systems, and formulations of glyphosate to glyphosate-tolerant soybean trough different regions of Brazil in different environmental conditions. Two experiments were conducted over two crop seasons. A 2 × 2 × 5 (formulations × stage of application × doses) factorial design was used in each of them, for a total of 20 treatments with four replications. The study assessed a series of variables related to agronomic performance such as total chlorophyll and yield. The results suggest some problems associated with post-emergent use of glyphosate in tolerant soybean crop as 5% total yield reduction even without phytotoxicity symptoms dependent of season. There was not found any formulation interaction with yield decrease.

Pastagens formadas com Cynodonn lemfuensis Vanderyst são excelentes alternativas para alimentação dos rebanhos. A competição de plantas daninhas pode ocasionar prejuízos à pastagem, sendo que Vernonia polyanthes e Desmodium incanum estão entre as principais espécies competidoras. O objetivo do presente trabalho foi avaliar a eficácia de diferentes herbicidas no controle de Vernonia polyanthes e Desmodium incanum, aplicados em alto e baixo volume de calda. O experimento foi instalado em uma área formada há mais de 10 anos por grama-estrela-africana (Cynodonn lemfuensis). O delineamento experimental empregado foi o de blocos ao acaso, no esquema fatorial 2x7, sendo dois volumes de calda 50 e 200 L ha-1 e sete herbicidas. Foram avaliadas as variáveis fitotoxicidade na grama Cynodonn lemfuensisaos 3, 7, 14, 21 e 28 dias após a aplicação (DAA) e controle das plantas daninha Vernonia polyanthes e Desmodium incanum aos 7, 14, 21 e 28 DAA. Não foram encontrados níveis altos de fitotoxicidade na pastagem. Os tratamentos que proporcionaram os melhores controles de Vernonia polyanthes e Desmodium incanum foram fluroxypyr meptílico + triclopyr, 2,4 D + aminopiralide e 2,4 D + picloram. Os volumes de calda não proporcionaram diferenças significativas na avaliação de controle aos 28 DAA para herbicidas, porém foram superiores para alguns tratamentos aos 7, 14 e 21 DAA. Com isso o menor volume de calda (50 L ha-1) torna-se uma alternativa viável no controle dessas espécies na pastagem.

Este trabalho teve por objetivo conhecer, apresentar e analisar métodos de avaliação da composição florística e fitossociológica de plantas daninhas das principais culturas agrícolas, baseando-se em dados bibliográficos de diversos autores, dentro da literatura pertinente. Além dos cálculos específicos, como densidade e frequência, outros métodos de análise fitossociológica foram considerados quando utilizados nos levantamentos sobre a ocorrência de plantas daninhas de interesse econômico na literatura e também a variabilidade de métodos que podem ser utilizados para a condução do trabalho a campo do manejo de plantas daninhas. É recomendável que o trabalho de identificação de plantas daninhas seja feito após a colheita, onde a infestação é maior e a riqueza é considerável, outrora, a identificação de plantas muda de acordo com a cultura implantada seja perene ou anual. Várias outras cultivares podem ser avaliadas em períodos diferentes do recomendado como, por exemplo, o feijão-caupi, avaliado na fase vegetativa, e o guaraná, avaliado por idade das plantas. Os métodos de avaliação variam muito de autor para autor, o que torna difícil a escolha e padronização de um método para a avaliação florística e fitossociológica das plantas invasoras, dentro de um contexto do MIPD (manejo integrado de plantas daninhas) e na geração de resultados científicos. Tal retrato caracteriza a diversidade e complexidade dos agroecossitemas, dentro do contexto dos sistemas produtivos, e aponta para a necessidade de mais estudos. Floristic and Phy Tosociological Survey of Weeds: A Review of Methods Employed ABSTRACT: Current survey aims at knowing, presenting and analyzing the evaluation methods of the floristic and phytosociological composition of weeds from the main agricultural environment. It is based on bibliographical data from several authors within the extant literature. Besides specific methods, such as density and frequency, other phytosociological methods were investigated when used in the survey on the occurrence of economically interesting weeds mentioned in the literature and also in the variability of methods that may be employed on the field for weed management. It should be recommended that weed identification may be done after harvest since during this period infestation is highest and richness abounds. Plant identification changes according to perennial or annual culture. Several cultivars should be evaluated during different periods than those recommended, such as the caupi-beans, evaluated during the vegetative phase, and guaraná, evaluated by the plant´s age. Evaluation method vary according to authors and it is rather difficult to select and standardize a method for the floristic and phytosociological evaluation of invading plants within the integrated management of weeds, and in the production of scientific results. The above characterizes the diversity and complexity of agroecosystems within the context of production systems. Further studies are required. KEYWORDS: Floristics; Methods; Weeds; Variability.

Some desiccation techniques for harvesting wheat may affect seed quality. The objective of this study was to evaluate the effect of different desiccant herbicides applied to the wheat crop and their effects on the production and seed quality. The experiment was conducted with cultivar COODETEC 150 (CD 150) in two sites in Palotina (Paraná state, Brazil) with a randomized block design consisting of 7 treatments (desiccation herbicides) and 4 replications. Desiccation was realized when 50% of the plants were in stage 80 with seeds in powdery or mass consistency. The variables analyzed were percentage of moisture content after harvest, Yield, hectoliter weight, mass of 100 seeds, vigor, germination, fresh mass of seedlings, dry mass of seedlings and root length. The herbicides carfentrazone-ethyl and clethodim were the ones that promoted greatest reduction in vigor. The herbicide paraquat caused reduction in seedling length. There was a reduction in the mass of 100 seeds for glufosinate-ammonium, clethodim, diquat and carfentrazone-ethyl. Glufosinate-ammonium, paraquat, glyphosate, clethodim and diquat caused reduction in yield. Desiccation of Cultivar CD 150 at stage 80 is not recommended, since plant Yield and physiological seed parameters were adversely affected by herbicides. Resumo: Algumas técnicas de manejo da cultura do trigo, como a dessecação pré-colheita podem afetar a produtividade e a qualidade fisiológica das sementes. O objetivo deste estudo foi avaliar o efeito de diferentes herbicidas dessecantes aplicados na cultura do trigo e seus efeitos sobre a produtividade e a qualidade das sementes. O experimento foi conduzido com a cultivar COODETEC 150 (CD 150), em dois ambientes de produção localizados no Município de Palotina - PR, sob o delineamento experimental de blocos casualisados, constituído de 7 tratamentos (herbicidas na dessecação) com 4 repetições. A dessecação foi realizada quando 50% das plantas apresentavam-se no estádio 80 com as sementes de consistência farinácea ou de massa. As variáveis analisadas foram umidade após a colheita, produtividade de sementes, peso hectolitro, massa de 100 sementes, germinação e vigor. Os herbicidas carfentrazone-ethyl e clethodim reduziram o vigor das sementes produzidas, e o herbicida paraquat reduziu o comprimento de plântulas. Ocorreu redução na massa de 100 sementes para o amônio - glufosinate, clethodim, diquat e carfentrazone-ethyl. O amônio - glufosinate, paraquat, glyphosate, clethodim e diquat reduziram a produtividade. A dessecação de plantas da cultivar CD 150 no estádio 80 não é recomendada, em decorrências dos efeitos negativos dos herbicidas nos parâmetros produtivos e fisiológicos das sementes de trigo.