Corynespora cassiicola affecting soybean

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 Borges3
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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Herbicides and water conditions on Ipomoea grandifolia control and enzyme activity

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 physiological indexes on black oak seeds

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 Souza5
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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Plant arrangement on soybean performance

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 Nardino4
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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Weed interference in canola

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 Tironi3
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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Drought on early development of wheat genotypes

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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Monocot weeds on Guinea grass

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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History of registry of soybean cultivars in Brazil

Two decades of national registry of soybean cultivars: updates and perspectives
Jardel Bazzan Dorneles1, Ivan Ricardo Carvalho1, Tamires da Silva Martins2, Natã Balssan Moura1, José Antonio Gonzalez da Silva1 and Francine Lautenchleger3
1Universidade Regional do Noroeste do Estado do Rio Grande do Sul, Ijuí, RS, Brasil
2Universidade Federal de Pelotas, Capão do Leão, RS, Brasil
3Universidade do Centro-Oeste, Guarapuava, PR, Brasil

Abstract
The aim was to reveal the trend and the pattern of registration of soybean cultivars in Brazil in recent decades and to contrast with future perspectives. This is a study carried out in 2019 at the Regional University of Northwestern Rio Grande do Sul – UNIJUÍ, where data were collected from 1998 to 2018. The online databases of the Ministry of Agriculture, Livestock and Food Supply (MAPA) were used, Food and Agriculture Organization (FAOSTAT) and United States Department of Agriculture (USDA), for data collection, the criterion used was that the cultivar was properly registered on the National Register of Cultivars (NRC) platform. In general, the aspects according to each year of launch of the cultivars are in favor of the best performance of the crop. They are correlated in the following modifications: plant architecture, resistance, seed size, indeterminate growth habit, flower colors, pods, hilums, presence of anthocyanin, peroxidase, seed brightness, densities and registered genotypes. With neural networks it was possible to classify 1818 soybean genotypes, divided into 18 profiles, also based on the search for 68 characters presenting 19 trends. With the work it was concluded that the year of launch of the cultivar is associated with: the intrinsic characteristics of the maintainer of the cultivar, the biotechnological event, the characteristics of the growth habit and the colorations of the flower, of the seed pod and of the hypocotyl. As the forecast is that in the coming decades new cultivars will be launched in Brazil, a correct positioning of specific genotypes for different environments is needed.

Highlighted Conclusions
1. The profile of traits of soybean cultivars has changed over the decades.
2. Brazilian soybean cultivars can be classified into 18 characteristic profiles.
3. The new cultivars are dependent on changes in the internal and external market.
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Saline stress tolerance by gibberelin in cactus

Gibberellic acid provides greater tolerance to saline stress in cactus seed germination
Ayslan Trindade Lima, Beatriz Araújo Oliveira and Marcos Vinicius Meiado
Federal University of Sergipe, Itabaiana, SE, Brazil

Abstract
It is important to understand the ecophysiological behavior and develop techniques applicable to conservation measures of species that inhabit arid and semi-arid ecosystem and are exposed to adverse environmental conditions. The objective of this study was to evaluate the effects of gibberellic acid (GA3) application during seed germination under saline stress conditions of a cactus. Pilosocereus gounellei susbp gounellei seeds were submitted to NaCl saline solutions at osmotic potentials of 0.0, -0.3, -0.6 and -0.9 MPa. For each osmotic potential, GA3 concentrations of 0, 100, 200 and 300 ppm were used. The results indicated that salt stress reduces germination percentage and synchronization as seeds are submitted to more negative osmotic potentials, as well as delaying germination time. However, this negative effect of NaCl was reversed when the seeds were subjected to the specific concentration of 100 ppm of gibberellic acid. Therefore, our study demonstrated that the application of GA3 at specific concentration improves the germinative metabolism of cactus seeds and promotes the acquisition of tolerance to saline stress conditions by increasing germinability, reducing germination time and increasing synchronization, thus representing a viable technique for seed germination and seedlings production under adverse environmental conditions.

Highlighted Conclusions
1. The application of GA3 at specific concentration improves the germinative metabolism of cactus seeds and promotes the acquisition of tolerance to saline stress conditions.
2. The application of GA3 represents a viable technique for seed germination and seedlings production under adverse environmental conditions.
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K salts inhancing herbicide action

Influence of K salts in enhanced herbicide activity
Deivid Araújo Magano1, Jerson V. Carús Guedes2, Shyam Pariyar3, Juergen Burkhardt3, Ivan Ricardo Carvalho1, José Antonio Gonzalez da Silva1 and Mauricio Hunsche3
1 Universidade Regional do Noroeste do Estado do Rio Grande do Sul, Ijuí, RS, Brasil
2 Universidade Federal de Santa Maria, Santa Maria, RS, Brasil
3 University of Bonn, Bonn, Alemanha

Abstract
Maximize process of pest control reducing loss in the agriculture process is fundamental. The aim this research was to achieve a different way to increase the herbicide activity, using potassium salts. Some experiments were conduct to analyze the efficiency of salts in enhanced the activity of two selected herbicides (paraquat and bromoxynil). Firstly, we checked the effects of chaotropic and kosmotropic potassium salts and their capability to cause damage in the foliar tissue, and made a dosage adequate to avoid these undesirable effects. Later on, we analyze the physiological impairments due salts using PAM-Fluorecence techniques, employing different kind of arrays to verify, the response and ability to increase the real damage in foliar tissues. The best performance was obtained with multiple droplets applied 48 hours earlier than herbicides, promoting an increase of 2 times more efficacy, for paraquat and bromoxynil.

Highlighted Conclusions
1. There is interaction between K salt and herbicides.
2. Microencapsulated herbicides consist in a strategy to combine with K salts.
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