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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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 Lautenchleger^3
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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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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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 Hunsche^3
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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Path analysis between yield components of wheat under different top-dressing nitrogen management
Alan Junior de Pelegrin¹, Maicon Nardino², Mauricio Ferrari³, Ivan Ricardo Carvalho⁴, Vinicius Jardel Szareski³, Antonio Costa de Oliveira¹, Velci Queiróz de Souza⁵ and Luciano Carlos da Maia^1
1 Universidade Federal de Pelotas, Capão do Leão, RS, Brasil
² Universidade Federal de Viçosa, Viçosa, MG, Brasil
³ SLC Agrícola, Porto Alegre, RS, Brasil
⁴ Universidade Regional do Noroeste do Estado do Rio Grande do Sul, Ijuí, RS, Brasil
⁵ Universidade Federal do Pampa, São Gabriel, RS, Brasil

Abstract
There is little research that addresses associations between the yield of wheat grains and their components in different managements of nitrogen fertilization top dressing. The objective this work linear estimate associations cause and effect between production components and the yield grains in the difference scenarios nitrogen (N) management in top dressing wheat two crops 2012 and 2013. Experimental design was randomized blocks, arranged scheme split-split-plot, with three genotypes × two crops × two source N × four management in top dressing. (3×2×2×4), in the three replications. Linear correlation and path analysis were estimate in the different N management. Management N in top dressing change magnitude linear associations in the wheat. Number fertile tillers independent management in top dressing have positive relation of cause and effect with yield grains in the wheat. Mass grains spike principal in the management II, III and IV prove positive relation cause and effect with yield grains in the wheat.

Highlighted Conclusions
1. Nitrogen management top dressing changes magnitude of linear association.
2. Number fertile tillers has positive cause relation with yield grains in wheat.
3. Mass of grains of main spike can have positive-causal relation with wheat yield grains depending on the top-dressing management.
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Univariate and multivariate controlled release nitrogen pairing on lettuce culture performance
Luiz Leonardo Ferreira¹, Alex Ribeiro Bastos¹, Ivan Ricardo Carvalho², Marilaine de Sá Fernandes¹, Núbia Sousa Carrijo dos Santos¹, Ariana Bertola Carnevale¹ and Priscila Ferreira Batista^1
1 Centro Universitário de Mineiros, Unidade de Biociências, GO, Brasil
² Universidade Regional do Noroeste do Estado do Rio Grande do Sul, RS, Brasil

Abstract
There are few studies in the literature that demonstrate the behavior of controlled release nitrogen fertilization in lettuce crop. Thus, the objective of this work was to evaluate, through univariate and multivariate pairing, the behavior of controlled release nitrogen sources on the performance of lettuce culture. The studies were conducted at the Horta dos Coqueiros property in Mineiros-GO, Brazil. The soil analyzes were taken before the experiment implementation, in the 0 to 20 cm layer, the soil was classified as NEOSSOL Quartzarenic. The experimental design was a randomized complete block design, with a 2x2x5 factorial design corresponding to 2 lettuce genotypes (Americana cv. Lucy Brow and Crespa cv. Vanda), submitted to two controlled release N sources (NitroMais and Polyblen). doses (0, 75, 150, 225, 300 kg ha^-1 of N) performing 4 repetitions. Transplantation occurred 20 days after sowing in trays, with plant spacing of 30×30. Data collection occurred 45 days after transplantation used 5 central plants of each plot. The analyzes were performed in the Rbio R interface, besides the Genes Software. The analysis of variance revealed triple interaction among the variables. Quadratic effect was expressed for both genotypes on protected nitrogen sources. For high performance of lettuce cultura in the Americana genotype cv. Lucy Brown recommends the application of protected nitrogen Polyblen at a concentration of 217.50 and NitroMais at 174.38 kg ha^-1 of N, as well as the source Polyblen at a dose of 146.50 kg ha^-1 of N in the genotype Crespa cv. Vanda.

Highlighted Conclusions
1. High performance of lettuce crop in the genotype Americana cv. Lucy Brown recommends the application of controlled release nitrogen Polyblen at a concentration of 217.50 and NitroMais at 174.38 kg ha^-1 of N.
2. In the Crespa cv. Vanda, the Polyblen source is at a dose of 146.50 kg ha^-1 of N.
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Pre-harvest herbicide application reduces the Italian ryegrass seed viability
Joanei Cechin¹, Alcimar Mazon¹, Silvio Thiago de Oliveira Raphaelli¹, Dirceu Agostinetto¹ and Leandro Vargas^2
1 Universidade Federal de Pelotas (UFPel), Pelotas-RS, Brasil
² Empresa Brasileira de Pesquisa Agropecuária (Embrapa Trigo), Passo Fundo-RS, Brasil

Abstract
Italian ryegrass (Lolium multiflorum Lam.) is a troublesome weed found in temperate agricultural fields, wherein the future infestations depend on the soil seed bank. The aim of this research was to evaluate Italian ryegrass seed viability subjected to herbicide application in different phenological stages of development. Experiments were carried out in a completely randomized experimental design with four repetitions. Paraquat, ammonium-glufosinate, iodosulfuron-methyl and clethodim herbicides were applied in three development stages (pre-spike, anthesis, and grain filling) and compared to the control. The effects were evaluated by percentage of control at seven, 14, and 28 days after application (DAA), seeds per plant, 1000 seeds weight, and percentage of germination, abnormal seedlings, dead seeds, viable and non-viable dormant seeds. Control was greater than 97% at 28 DAA, with a decrease of more 90% for seed per plant, and strong reduction of 1000 seeds weight for the herbicides applied up to the anthesis stage. At the grain filling stage, clethodim reduced seed production by 18% and 1000-seeds weight by 36% compared to the control. Ammonium-glufosinate and paraquat herbicides applied up to the anthesis stage reduced seed viability by more than 98%. Overall, herbicide application reduces seed production, seed weight and viability, especially when applied before the grain filling stage.

Highlighted Conclusions
1. Herbicide application up to the anthesis developmental stages reduces seed production, 1000 seeds weight, and seed viability.
2. Paraquat was the best herbicide to reduce seed production per plant, 1000-seeds weight and, viability of Italian ryegrass seeds, regardless of development stages.
3. Reducing future infestations of Italian ryegrass in cropping systems depends on herbicide application before the grain filling.
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Cause and effect relationships, multivariate approach for inoculation of Azospirillum brasilense in corn
Luiz Leonardo Ferreira¹, Gean Ferreira Santos¹, Ivan Ricardo Carvalho², Marilaine de Sá Fernandes¹, Ariana Bertola Carnevale¹, Karine Lopes¹, Roselaine Lages Fonseca Prado¹, Francine Lautenchleger³, Alexandre Igor de Azevedo Pereira⁴ and Carmen Rosa da Silva Curvêlo^4
1 Centro Universitário de Mineiros, Unidade de Biociências, GO, Brazil
² Universidade Regional do Noroeste do Estado do Rio Grande do Sul, Departamento de Estudos Agrários, RS, Brazil
³ Universidade do Centro-Oeste (UNICENTRO), Guarapuava, PR, Brazil
⁴ Instituto Federal Goiano, IF Goiano, Urutaí, Mineiros, GO, Brazil

Abstract
Beneficial bacteria to corn crop, such as Azospirillum brasilense, can bring consistent gains for the farmer. In this sense, the objective of this work was to evaluate the cause and effect relationships and multivariate approach of Azospirillum brasilense inoculation in corn genotypes. The study was conducted in the municipality of Mineiros-GO, Brazil. The experimental design was a randomized block in 12×2 factorial, corresponding to twelve corn hybrids (20A78, 2B587, 2B610, 30F53, CD3770, CD384, DKB310, LG36701, LG6030, MG652, P3646 and PB9110), submitted to (absence and presence) of A. brasilense. The soil preparation was carried out in the conventional system with population of 60 thousand plants. Formulated 8-25-15 at a dose of 480 kg ha^-1 was used. Pest control was performed when necessary. At the end of the experiment the variables were taken. The obtained data were submitted to the assumptions of the statistical model, verifying the normality and homogeneity of the residual variances, as well as the additivity of the model. Analyzes were performed at the Rbio interface of R and Genes. The summary analysis of variance with the mean square MS and significance by the F test revealed significant interaction between hybrid x A. brasilense. Corn hybrids showed higher expressiveness in yield components in the presence of Azospirillum brasilense applied in seed treatment. The number of grains per ear and the thousand grain mass were directly responsible for the increase of corn hybrids yield in the presence and absence of Azospirillum brasilense.

Highlighted Conclusions
1. Corn hybrids showed higher expressiveness in yield components in the presence of Azospirillum brasilense applied in seed treatment.
2. The number of grains per ear and the thousand grain mass were directly responsible for the increase of corn hybrids yield in the presence and absence of Azospirillum brasilense.
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