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Soy is the main commodity in Brazilian agriculture, however its cultivation faces a series of challenges, such as pests, diseases, soil nutritional imbalance and other factors. The objective of this work was to verify the influence of different previous cultures on the productivity and nutritional quality of soybean grains. The experiment took place in the city of Pejuçara, in the state of Rio Grande do Sul - Brazil, in the 2019/20 agricultural season. The experiment took place in a 5X4 factorial scheme, in a randomized block design with four replications. The treatments composing by the combination of five soybean genotypes (BMX Lança IPRO, M 5838 IPRO, BMX Raio IPRO, BMX Zeus IPRO, DM57i52 IPRO), and four previous coverages. We measured morphological, productive and physicochemical characters of soybean grains. The data obtained were submitted to a density analysis, after which Pearson's linear correlation was performed in order to show the linear trend of association between the characters. Subsequently, Principal Component Analysis was performed to assess the interaction between the variables studied and the treatments. Moreover, cluster analysis to verify the levels of similarity that group the treatments. It is not possible to perceive a significant effect between the variables analyzed and the predecessor cultures used, in addition to the fact that in relation to bromatological quality, plant chemistry, productivity and nutritional quality of the grains, they presented values consistent with the literature. Thus, conclusion is that both predecessor cultures (oat, pasture, wheat and linseed) did not interfere directly in the soybean crop. Keywords: Glycine max L., bioactive compounds, main components. [ABSTRACT FROM AUTHOR]

This work aims to highlight the best soybean genotypes for specific environments in the Northwest Region of the State of Rio Grande do Sul. The experiment was carried out in the 2018/19 crop season in fifteen cultivation environments in the Northwest region of the state of Rio Grande do Sul, using 52 soybean genotypes in 15 growing environments. The experimental design used was lattice with treatments (growing environments) arranged in three replications. In each useful area of the experimental unit, the grain productivity of the genotypes was evaluated. Then, the Restricted Maximum Likelihood (REML) method was applied to estimate the variance components and genetic parameters. The following variance components were estimated: Genetic variation (Vg) and phenotypic variation (Vp). The genetic parameters estimated were: broad sense heritability (H²), coefficient of genotypic variation (CVg), coefficient of residual variation (CVe), ratio between genetic and residual coefficient (CVr) and selective accuracy (Ac). The phenotypic expression of grain yield is determined by 17% due to genetic effects and 83% by the environment. The NS 6909 RR IPRO, NS 5445 IPRO, DM 5958 IPRO and DM 6563 IPRO genotypes showed greater genetic gains for grain yield. The environments Doutor Maurício Cardoso (RS), Nova Ramada (RS) and Independência (RS) are characterized as favorable environments. [ABSTRACT FROM AUTHOR]

Phytosociology is a set of ecological assessment methods that aim to provide a view of plant species distributions within a plant assemblage. The objective of the current study was to identify and quantify the plants designated as weeds in a glyphosate-resistant soybean crop, using a phytosociological survey of a conventional planting system on the Fazenda Agrosantos (09°27'4124.4" S and 45°01'00.4" O), Vale do Gurguéia, Monte Alegre municipality Piauí state, Brazil. The site lies at a mean altitude of 652 m. Field collections were made 15 days after initial soya planting. For sampling, a 0.40 x 0.40 m quadrat was used, thrown randomly twenty times within the experimental area. Weeds were identified and quantified using the sum of the samples obtained from the quadrat samples. Plants that lay within the quadrat were identified, counted and collected for identification, which was carried out by comparison with specialist bibliographies and weed identification manuals. Evaluated variables were: frequency, density, abundance, relative frequency, relative density, relative abundance and species importance value index. In the soybean cultivation area, 60% of the sampled species were Eudicotyledons, and a total of 8 botanical families and 10 weed species were identified. The species Cenchrus echinatus, Ipomoea asarifolia (Desr.) Roem. & Schult, Amaranthus retroflexus L. and Zea mays L showed the highest values for the analyzed variables, and should therefore be of special attention to soybean producers in the region of Vale da Gurguéia, Piauí, Brazil. [ABSTRACT FROM AUTHOR]

Soybean plants are constantly exposed to abiotic stresses that compromise production, among these, in areas of Brazilian Cerrado, mainly in the northeast region, periods of drought can occur due to irregular and summer rainfall. Thus, the objective of this work was to determine the physiological response of Monsoy 9350 soybean at different stages of development, when subjected to water stress. The experiment was conducted in a greenhouse, in the experimental area of the campus of the Universidade Federal do Piauí (UFPI) in Bom Jesus-PI, assembled in a 3x3 factorial scheme, with water in the soil at three levels (50% VTP; 75% VTP and 100% VTP) and three phenological phases, budding to bloom (BF); bloom to complete grain filling (FE) and budding to complete grain filling (BE), the experiment consisted of 9 treatments, in a randomized block design, containing 4 replications. The evaluation of the experiment was standardized according to the phenological stages and not according to the time. The following variables were evaluated: plant height, internode length, internode thickness, number of branches, chlorophyll index, number of flowers, insertion of the first pod and number of pods. According to the evaluated results, the water stress in soybean for cultivating Monsoy 9350 mainly affects the period from budding to bloom, interfering negatively in height, chlorophyll and number of pods. [ABSTRACT FROM AUTHOR]

Inoculation of agronomic crops with arbuscular mycorrhizal fungi is a promising agronomic practice, which has been solidified by recommendation of recently-registered inoculants in Brazil. The need to understand effects of different inoculant formulations is, therefore, a fundamental aspect for basic and applied research. The aim of this study was to evaluate inoculum potential of the arbuscular fungus R. clarus cultivated in a pot culture system compared to the in vitro system and test the effect of both on growth and yield of soybean. Inoculum potential was tested in greenhouse conditions using maize as host plant. Values of root colonization showed that inoculum potential was 7% higher in the in vitro system. In order to evaluate the effects of both inoculants, an experiment was carried out in greenhouse conditions following a completely randomized design with three treatments and six replicates. The inoculant produced in vitro increased all nodulation parameters, but did not affect shoot mass or nitrogen of soybean plants. Grain yield, however, was 20% higher with the use of pot-produced inoculum. Pot culure system is the most promising technique to produce soybean inoculum, considering possible yield gains. [ABSTRACT FROM AUTHOR]

The soybean, one of the most important crops in Brazilian agriculture, is a profitable crop due the use of new technologies in the development of new cultivars, which contain more biotechnologies that turn its management easier. Among these technologies, there is the INTACTA RR2 PRO®, which was recently released. However, there are few studies to show the most yielding cultivars indicated to Marechal Cândido Rondonm, Paraná State, Brazil. Therefore, the aim of this study was to evaluate the performance of some IPRO soybean cultivars recommended or cultivated in Western Paraná and identify the most yielding ones. A couple of agronomic characteristics were evaluated, focusing in the yield and cycle. The randomized block design was used, with four replications. The data was submitted to variance analysis and the averages were compared following the Tukey Test (p ≤ 0.05). The results indicate that the cultivars with the shortest cycles are more adapted and provided the highest yields in the region. [ABSTRACT FROM AUTHOR]

The increase in costs of selected and certified soybean seeds is evident in recent years. Knowing that farmers can use saved seeds, the aim of the study was to evaluate the physiological and sanitary quality of saved seeds produced in the first and the second crop in Western Paraná State, Brazil, compared to commercial seeds. The experiment was conducted at Seed Laboratory of the State University of West Paraná, with seeds of soybean cultivar Vmax RR (NK 7059RR), arranged in 5x3 factorial with four replications. For the first factor treatments refer to seed lots with different sources of production: two lots in the second crop of 2010 with and without seed treatment (ST), two lots of first crop of 2010/2011 with and without ST and one commercial lot of seeds 2010/2011 with ST. The second factor is related to accelerated aging, being maintained for 0, 24 and 48 hours at a temperature of 41 °C. To check the quality of seeds were evaluated germination, electrical conductivity and first germination in September 2011. Also was assessed the pathogens present in the seeds used in the treatments. Commercial seed scored higher germination, first count, number of normal seedlings, as well as the accelerated aging test as the electrical conductivity test. Commercial seed had vigor and superior germination qualities than saved seeds, not being viable use seeds saved from the previous crop or second crop with pest problems. [ABSTRACT FROM AUTHOR]