Weed management with pre-emergent herbicides in soybean crops
Helis Marina Salomão¹, Michelangelo Muzell Trezzi¹, Matheus Viecelli², Fortunato De Bortoli Pagnoncelli Junior², Felipe Patel², Leticia Damo³ and Gilvane Frizzon^2
1Federal University of Technology, Pato Branco, PR, Brazil.
²Independent Agronomist, Brazil.
³Federal University of Viçosa, Viçosa, MG, Brazil.

Abstract
The use of pre-emergent herbicides in soybean crops is fundamental, among other reasons, to maintain a clean crop in the initial stages, alter mechanisms, and consequently manage weed resistance. However, there is a considerable demand for information about the efficiency and selectivity of systems with residual herbicides applied in different modalities. This study evaluated the efficiency and selectivity of pre-emergent herbicides doses applied singly or mixed in a tank on soybean crops. The experiment was installed in randomized block design with 21 treatments and four repetitions. The treatments were composed of weeded and unweeded witnesses and pre-emergent application of isolated S-metolachlor or the herbicides diclosulam, flumioxazin, and sulfentrazone isolated or together with S-metolachlor in different doses with the addition of post-emergent S-metolachlor (soybean stage V2). Associations of residuals herbicides applied in pre-emergence or sequential mode increased the control levels of mono and dicotyledonous weeds. The treatments, including single or associated diclosulam and the systems with S-metolachlor sequentially, caused the most significant toxicity (up to 17%) for soybeans. High doses of S-metolachlor (2592.0 g ha^-1), diclosulam (33.6 g ha^-1), and the associations of S-metolachlor + diclosulam, S-metolachlor + flumioxazin, and S-metolachlor + diclosulam with sequential S-metolachlor should be avoided to obtain higher levels of soybean yield. The use of pre-emergent herbicides demonstrated to be an efficient and viable option to control weeds in soybean crops.

Highlighted Conclusions
1. The association of residual herbicides generally increases the control levels of mixed natural infestations of mono and dicotyledons weeds.
2. It is possible to associate the grain yield of a soybean crop with the control efficiency of weed species and the toxicity of herbicides in the crop.

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An algal sulphated polysaccharide capable of reducing mycotoxin biosynthesis by Fusarium
Rafael Dal Bosco Ducatti¹, Siumar Pedro Tironi² and Sergio Miguel Mazaro^1
1Federal University of Technology – Paraná (UTFPR), Pato Branco, PR, Brazil.
²Federal University of Fronteira Sul (UFFS), Chapecó, SC, Brazil.

Abstract
The incidence of Fusarium sp. in maize, besides causing drops in yields also causes the bromatological quality of the final product to decrease and mycotoxin accumulation to increase. Nineteen field trials have been performed in 4 different states of Brazil during three consecutive harvest seasons using 17 different maize cultivars aiming at assessing the use of carrageenan as a biological compound to decrease mycotoxin biosynthesis and accumulation and, increase maize silage yields and quality. Overall, carrageenan has proven to raise the bromatological quality of the silage, increase yields and decrease fumonisine and deoxynivalenol contamination by 50.4% and 45.7%, respectively.

Highlighted Conclusion
Carrageenan has the capability to help on the suppression of DON and FUMO biosynthesis/accumulation and to help on the increase of the bromatological quality of maize silage.
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Phosphorus partition, phytic acid concentration and grains productivity of beans cultivars as a response to phosphate nutrition
Ritieli Baptista Mambrin¹, Darlene Sausen², Diogo Moura¹, Ivan Ricardo Carvalho³, Vinícius Jardel Szareski⁴ and Giordano Gelain Conte^4
1Centro De Ensino Superior Riograndense, Marau, RS, Brasil.
²Universidade Federal do Rio Grande do Norte, Parnamirim, RN, Brasil.
³Universidade Regional do Noroeste do Estado do Rio Grande do Sul, Ijuí, RS, Brasil.
⁴Universidade Federal de Pelotas, Capão do Leão, RS, Brasil.

Abstract
The objectives of this work were to evaluate the phosphorus partition in tissues, in different growth stages, the phytic acid concentration in grains and the beans yield, as a response to the phosphorus supply in the culture environment, and the analysis of the association between these characters. The experiments were conducted in non-acclimatized greenhouse. The data was submitted to variance analysis, considering all the effects as fixed, with exception of the error, which was considered random. Since it was significant the effect of the triple interaction phosphorus concentration x genotype x growing season (C x G x E), it was realized the deployment of it in three double interactions with the use of complex variance. The phosphorus values in common bean leaves at initial growing stages are close to the ones found in grains. For the genotypes Pérola and IPR88 Uirapurú, the highest phosphorus values in plants tissues and of phytic acid occurred in phosphorus concentrations in the nutritive solution between 1.38 and 2.00 mmol L^-1. Phosphorus concentrations in the nutritive solution between 1.37 and 1.96 mmol L^-1 result in higher phosphorus concentration in leaves at third trifoliate leaf, in stem at flowering, in leaves, stem and legumes at legumes filling and grains at maturation. Also, higher phytic acid concentration in grains, at the fall-winter and spring-summer seasons. The evaluation of phosphorus concentration in the vegetal tissues from the legume filling stage is promising and allows indirect selection to grains productivity.

Highlighted Conclusion
The concentration of P in plant tissues during the legume filling stage is promising and allows indirect genetic selection to grains productivity.
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Yield and economic losses caused by Corynespora cassiicola on soybean under chemical control
Deivid Sacon¹, Alexandre Jacques Bottan², Laura Caroline Zanella², Aline Netto² and Leandro Luiz Borges^3
1Instituto de Biotecnologia Aplicada à Agropecuária, Viçosa, MG, Brasil.
²ABC Agrícola, Sapezal, MT, Brasil.
³Universidade do Estado de Minas Gerais, Passos, MG, Brasil.

Abstract
Target Spot is an important disease in soybean caused by the necrotrophic fungus Corynespora cassiicola. Recently, this fungus has gained importance in large crops such as soybeans and for its insensitivity fungicides reports. In this study, three assays were carried out with different application treatments in order to evaluate fungicide applications to control Target Spot and their interference on soybean productivity. Different application treatments were tested including fungicide products, doses, mixtures and number of applications, as well as estimate the application’s economic viability. Cultivar TMG 2378 IPRO was used and the applications were performed with a CO₂ sprayer pressurized in a randomized block design with four replications. The harvest of 2.7 m² useful area in the plot center was carried out with a stationary plot harvester and the yield was estimated for kg ha^-1. For an economic analysis of the application treatments, the soybeans sale was considered at a fixed price of US$ 264 t^-1, while the operating cost at a value of US$ 8. The fungicides spraying cost was estimated in kg of grains ha^-1 based on the average of two budgets made. The fungicide mixtures bixafen+prothioconazole+trifloxystrobin+mancozeb and trifloxystrobin+ prothioconazole+mancozeb presented both yield increase and economic viability compared to control.

Highlighted Conclusion
Mixtures of bixafen+prothioconazole+trifloxystrobin+mancozeb and trifloxystrobin+ prothioconazole+mancozeb have yield and economic viability to control Corynespora cassiicola.
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Control of Ipomoea grandifolia and antioxidant enzyme activity with bentazon and glyphosate at times and soil water conditions
Helis Marina Salomão, Michelangelo Müzell Trezzi, Fortunato de Bortoli Pagnoncelli Junior, Adriano Suchoronczek, Matheus Viecelli and Katia Cristina Dalpiva Hartmann
Federal University of Technology (UTFPR), Pato Branco, PR Brazil.

Abstract
Weed management with herbicides requires favorable environmental conditions, that maximize efficiency, such as soil humidity and timing of application. The aim of this study was to assess the effect of the application timing of bentazon and glyphosate herbicides on the control and activity of antioxidant enzymes in Ipomoea grandifolia, under different conditions of soil water availability. Two experiments, one for each herbicide (bentazon and glyphosate), were conducted in a factorial design with four replicates. The first factor was the two rates of each herbicide (504 and 720 g i.a. ha^-1 of bentazon and 651 and 911.4 g i.a. ha^-1 of glyphosate). The second factor was the six application times (1 am; 5 am; 9 am; 1 pm; 5 pm and 9 pm). The third factor, soil water content (100% and 50% of field capacity). Plus, two controls without herbicide application. At 21 days after application (DAA) of bentazon and 28 DAA of glyphosate, the fresh mass of the aboveground plants was measured. In addition, the activities of the enzymes superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX) were determined. For plants under water restriction, an increase of approximately 20% in fresh mass was observed compared in plants without water restriction, indicating lower control efficiency under water stress condition. For bentazon, at 1 pm has been observed the lowest herbicide efficiency, the other times were the most efficient, and did not differ. For glyphosate, the application at 9 am was the most efficient, while at 1 am provided the worst control efficiency. Higher CAT and SOD activities after bentazon application were observed at 1 pm. Among the three enzymes evaluated, SOD presented the highest activity after glyphosate application. Generally, the times of the day with the highest peak of enzymatic activity were distinct between with and without water restriction.

Highlighted Conclusions
1. Water restriction reduces the efficiency of bentazon and glyphosate.
2. Better efficiency for bentazon was observed at 1 am, 5 am, 9 am, 5 pm and 9 pm.
3. Better efficiency for glyphosate was observed at 9 am.
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Akaike criteria and selection of physiological multi-character indexes for the production of black oat seeds
Natã Balssan Moura¹, Ivan Ricardo Carvalho¹*, José Antonio Gonzalez da Silva¹, Murilo Vieira Loro¹, Maurício Horbach Barbosa², Francine Lautenchleger³, Volmir Sergio Marchioro⁴ and Velci Queiróz de Souza^5
1Northwestern Regional University of the State of Rio Grande do Sul, Ijuí, RS, Brazil.
²Tropical Genetic Improvement, Rondonópolis, MT, Brazil.
³University of the Midwest (Unicentro), Guarapuava, PR, Brazil.
⁴Federal University of Santa Maria, Frederico Westphalen, RS, Brazil.
⁵Federal University of Pampa, São Gabriel, RS, Brazil.

Abstract
The selection of characters provides the identification of complex characteristics, the objective of the work was to use the Akaike criteria and multiple regressions to prove the multi character selection and the interrelationships based on the Phenotypic, Standardized, Willians, Multiplicative, Mulamba and Mock indexes for the selection of black oat genotypes with high physiological potential of seeds. The study was conducted in Fortaleza dos Valos – RS in an experimental design used in randomized blocks with three replications. The trends for the selection of various Step Wise variables and the Akaike criteria are similar for most selection indices. For selection indexes, the phenotypic index and the standardized index correlate with the morphological characteristics, being mainly for the number of tillers. The genetic and multiplicative indices correlate with the characteristics of the seed. The phenotypic selection index was the one that stood out the most, regardless of the criterion used. This index correlates positively with the number of tillers. To select plants that present superior quality seeds, individuals with characteristics such as smaller panicles and with less spikelet ramifications and less panicle mass are sought.

Highlighted Conclusions
1. The phenotypic selection index was the one that stood out the most.
2. To obtain quality seeds, plants with smaller panicles, less spiky branching and less panicle mass are sought.
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Agronomic performance of soybean with indeterminate growth habit in different plant arrangements
Daniel Augusto Silveira¹, Beatriz Braga Silveira², Cássio Egídio Cavenaghi Prete², Carlos André Bahry³ and Maicon Nardino^4
1Syngenta Proteção de Cultivos Ltda, Londrina, PR, Brasil.
²Universidade Estadual de Londrina, Londrina, PR, Brasil.
³Universidade Tecnológica Federal do Paraná, Dois Vizinhos, PR, Brasil.
⁴Universidade Federal de Viçosa, Viçosa, MG, Brasil.

Abstract
Plant arrangements are a practice that has remained constant for decades, with little research about soybeans, with contrasting rainfall conditions. The purpose of this work was to evaluate the agronomic performance of indeterminate soybean with variation for the plant arrangements, populations and in cultivation of crops. The research was conducted in Arapongas-PR with an experimental design of randomized blocks, organized in a 6x3x2 factorial scheme, with four replications. The variation factors were six populations (100, 200, 300, 400, 500 and 600 thousand plants ha^-1), three plant arrangements (0.25 cm, 0.50 cm and 0.25×0.50 cm in paired-rows) and two cultivation of crops. The statistical analysis sought to evaluate the interactions and break down the simple effects and the main effects. Row spacing influenced the variables grain yield, height of the first pod insertion, plant height and leaf area index. Populations with up to 300 thousand plants reached the highest levels of grain yield. The plant arrangement for the paired-rows is superior to traditional spacing, with 4,732 kg ha^-1 for the spacing 0.25×0.50 m, 3,817 kg ha^-1 for the spacing 0.50 m and 3,628 kg ha^-1 for the spacing 0.25 m.

Highlighted Conclusions
1. The agronomic performance of the CA7442 RR1 soybean cultivar, with undetermined habit, is influenced by the spatial arrangement, by the plant population.
2. There is a tendency to reduce grain yield in higher populations under water stress conditions.
3. The arrangement of paired-rows in relation to single-rows revealed grain yield 20% higher for harvests with normal precipitation
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Periods of weed plant interference in canola
Daiani Brandler¹*, Leandro Galon¹, Altemir José Mossi¹, Thalita Pedrozo Pilla¹, Rodrigo José Tonin¹, Cesar Tiago Forte², Felipe Bianchessi¹, Emanuel Rodrigo de Oliveira Rossetto¹ and Siumar Pedro Tironi^3
1Federal University of Fronteira Sul, Erechim, RS, Brazil.
²Federal University of Santa Maria, Santa Maria, RS, Brazil.
³Federal University of Fronteira Sul, Chapecó, SC, Brazil.

Abstract
The objective of this work was to determine the periods of interference of turnip, ryegrass and black oats infesting the canola crop. Two models of interference were studied: first, the canola cohabited with weeds for increasing periods up until 0, 7, 14, 21, 28, 35 and 42 days after the emergency (DAE) and throughout the cycle; second, the culture was kept free of the infestation for the same periods described previously. At 51 DAE, the variables related to canola and weed morphophysiology were determined. In the harvest of the crop, was measured the number of siliques, a thousand grain mass and grain yield. The physiological variables, photosynthetic rate, internal CO₂ concentration, perspiration rate, stomach conductance of water vapors, carboxylation efficiency and efficient water use did not show significant variation. The dry mass was reduced by 79.21% when canola culture was always in competition with ryegrass, turnip and black oat weeds. The number of siliques and the mass of one thousand grains also decreased as the period of competition with the turnip, ryegrass and black oat weeds increased. The period before the interference (PAI) of the weeds ryegrass, turnip and black oats goes up to 25 DAE of canola. The critical interference prevention period (PCPI) for canola culture goes from 25 to 60 DAE. And the total interference prevention period (PTPI) is 60 DAE. Interference from weeds has reduced by 94.05% the productivity of canola grains when it has not received control of ryegrass, turnip and black oats.

Highlighted Conclusion
Weeds have to be controlled from 25 to 60 days after emergence to prevent canola yield reduction by up to 94%.
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Morphologically accessing wheat genotypes in response to drought on early stages of development
Rebeca Catanio Fernandes, Victoria Freitas de Oliveira, Luciana Dallegrave Schroeder, Alice Pereira de Jesus, Carlos Busanello, Mateus Ferreira Santos, Vívian Ebeling Viana, Antonio Costa de Oliveira and Camila Pegoraro
Universidade Federal de Pelotas, Pelotas, RS, Brasil

Abstract
As an alternative to decrease the internal deficit of wheat production in Brazil is the expansion of the cultivation area to the Cerrado, in which the occurrence of drought periods is common, causing damage when it occurs during the crop establishment and during the reproductive stage, thus develop genotypes tolerant to dry environments is essential. Development of drought-tolerant genotypes depends on the presence of genetic variability, thus the identify the variability within the accessions cultivated in Brazil allows the selection of genotypes with tolerance levels for use in crossing blocks. Thus, the objective of this study was to identify wheat genotypes displaying drought tolerance in the early stages of development through morphological characterization. In this sense, here we investigate 104 wheat genotypes cultivated in Brazil in response to drought at early stage of development. The seeds were deposited on germination paper with water and with PEG6000 at -0.5 MPa solution, simulating the control and drought stress conditions, respectively, and were kept in a germination chamber for eight days. The number of roots, root and shoot length, and root and shoot dry mass were measured, and a relative performance was calculated. The results were subjected to analysis of variance, Scoot Knott test and a Pearson correlation. The genetic distance was calculated based on the Euclidean distance and for the grouping the UPGMA method was applied. The principal component analysis was also performed. Based on the shoot and root phenotyping, it was possible to verify that the evaluated wheat panel displayed genetic variability associated with drought and present potential genotypes to drought tolerance on early stages of development, as FPS Nitron, which is a target genotype as a genitor to be used in crossing blocks aiming drought tolerance.

Highlighted Conclusions
1. The wheat genotypes growing in Brazil present genetic diversity in response to drought stress at early developmental stages.
2. FPS Nitron was less affected in drought stress condition which suggest its inclusion in crossing blocks.
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Guinea grass yield under interference of monocotyledon weeds
Prissila Pereira dos Santos e Araújo, Ricardo Fagundes Marques, Guilherme Henrique Rodrigues Pinheiro, Rodrigo Marques de Souza and Sidnei Roberto de Marchi
Universidade Federal de Goiás, Antônio Cândido, GO, Brasil

Abstract
Pastures are the main source of food for herds; thus, it is essential to understand the interference relationships between forage species and weeds to use management strategies properly and to obtain forage production with satisfactory nutritional value. The objective of this study was to evaluate the effect of different periods of coexistence with major monocotyledonous weeds on the alteration of the canopy structure and the productive components of Panicum maximum Jacq. cv. Guinea under pasture reform condition. The experiment was set up in a randomized block design, with four replications, and the treatments were represented by increasing periods of coexistence, namely: 0, 15, 30, 45, 60, 75 and 90 days after seedling emergence. Forage plants were evaluated at 90 days after emergence for their main structural and productive characteristics. The findings show that the presence of monocotyledon weeds negatively interferes in the structural and productive aspects of P. maximum Jacq. cv Guinea. Therefore, control measures should be adopted using a period before interference (PBI) less than sixteen days of coexistence with the monocotyledon weed community.

Highlighted Conclusions
1. Increased period of coexistence with weeds affects the Guinea grass leaf:stem ratio.
2. Guinea grass leaf volumetric density is negatively affected by an increased period of coexistence with weeds.
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