Survival and development of Spodoptera eridania, Spodoptera cosmioides and Spodoptera albula (Lepidoptera: Noctuidae) on genetically-modified soybean expressing Cry1Ac and Cry1F proteins.

BACKGROUND: Spodoptera eridania (Stoll), S. cosmioides (Walker) and S. albula (Walker) (Lepidoptera: Noctuidae) are considered secondary pests of soybean in South America. The genetically-modified soybean DAS-444Ø6-6 × DAS-81419-2 with tolerance to 2,4-dichlorophenoxyacetic acid (2,4-D), glyphosate and ammonium glufosinate herbicides (event DAS-444Ø6-6) and insect-resistance due to expression of Cry1Ac and Cry1F Bt proteins (event DAS-81419-2) may provide a potential tool for integrated pest management (IPM) of these species in soybean fields. Based on this, we conducted bioassays to evaluate the survival and development of S. eridania, S. cosmioides and S. albula fed on Cry1Ac/Cry1F-soybean leaf tissue. RESULTS: Spodoptera eridania and S. cosmioides fed on Cry1Ac/Cry1F-soybean showed longer developmental time, lower larval and egg to adult survival compared to those fed on non-Bt soybean, reducing the population growth of these species. Spodoptera albula also had lower larval survival and number of insects that reached adulthood on Cry1Ac/Cry1F-soybean. However, no significant effects of Cry1Ac/Cry1F-soybean on population growth parameters were detected in this species. CONCLUSIONS: Soybean with stacked events DAS-444Ø6-6 × DAS-81419-2 expressing Cry1Ac/Cry1F Bt proteins provide population suppression of S. eridania and S. cosmioides. However, this Bt soybean had minimal effects on S. albula, and is unlikely to have negative population-level effects on this species. It is expected that under field conditions, other control tactics must be integrated with Cry1Ac/Cry1F-soybean for the management of these Spodoptera species. © 2020 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Compositional analysis of soybean event IND-ØØ41Ø-5.

Soybean (Glycine max L.) is the world's largest source of protein feed and the second largest source of vegetable oil. Water restriction is the main limiting factor to achieve maximum soybean yields. Therefore, development of varieties that maintain yield under environmental stresses is a major objective of soybean breeding programs. The HaHB4 (Helianthus annuus homeobox 4) gene from sunflower encodes for a transcription factor involved in the plant´s tolerance to environmental stress. The introduction of HaHB4 in soybean led to the development of event IND-ØØ41Ø-5 (HB4® soybean), which displayed higher yield in environments having low productivity potential, compared with the parental control variety. Compositional analyses of soybean event IND-ØØ41Ø-5 were conducted both in Argentina and the United Sates. A total of 44 components were analyzed in grain and 9 components in forage. Based on the results of these studies it was concluded that soybean event IND-ØØ41Ø-5 was compositionally equivalent to its non-transgenic parental control.

An Interdisciplinary Approach to Study the Performance of Second-generation Genetically Modified Crops in Field Trials: A Case Study With Soybean and Wheat Carrying the Sunflower HaHB4 Transcription Factor.

Research, production, and use of genetically modified (GM) crops have split the world between supporters and opponents. Up to now, this technology has been limited to the control of weeds and pests, whereas the second generation of GM crops is expected to assist farmers in abiotic stress tolerance or improved nutritional features. Aiming to analyze this subject holistically, in this presentation we address an advanced technology for drought-tolerant GM crops, upscaling from molecular details obtained in the laboratory to an extensive network of field trials as well as the impact of the introduction of this innovation into the market. Sunflower has divergent transcription factors, which could be key actors in the drought response orchestrating several signal transduction pathways, generating an improved performance to deal with water deficit. One of such factors, HaHB4, belongs to the homeodomain-leucine zipper family and was first introduced in Arabidopsis. Transformed plants had improved tolerance to water deficits, through the inhibition of ethylene sensitivity and not by stomata closure. Wheat and soybean plants expressing the HaHB4 gene were obtained and cropped across a wide range of growing conditions exhibiting enhanced adaptation to drought-prone environments, the most important constraint affecting crop yield worldwide. The performance of wheat and soybean, however, differed slightly across mentioned environments; whereas the improved behavior of GM wheat respect to controls was less dependent on the temperature regime (cool or warm), differences between GM and wild-type soybeans were remarkably larger in warmer compared to cooler conditions. In both species, these GM crops are good candidates to become market products in the near future. In anticipation of consumers' and other stakeholders' interest, spectral analyses of field crops have been conducted to differentiate these GM crops from wild type and commercial cultivars. In this paper, the potential impact of the release of such market products is discussed, considering the perspectives of different stakeholders.

Successful field performance in warm and dry environments of soybean expressing the sunflower transcription factor HB4.

Soybean yield is limited primarily by abiotic constraints. No transgenic soybean with improved abiotic stress tolerance is commercially available. We transformed soybean plants with genetic constructs able to express the sunflower transcription factor HaHB4, which confers drought tolerance to Arabidopsis and wheat. One line (b10H) carrying the sunflower promoter was chosen among three independent lines because it exhibited the best performance in seed yield, and was evaluated in the greenhouse and in 27 field trials in different environments in Argentina. In greenhouse experiments, transgenic plants showed increased seed yield under stress conditions together with greater epicotyl diameter, larger xylem area, and increased water use efficiency compared with controls. They also exhibited enhanced seed yield in warm and dry field conditions. This response was accompanied by an increase in seed number that was not compensated by a decrease in individual seed weight. Transcriptome analysis of plants from a field trial with maximum difference in seed yield between genotypes indicated the induction of genes encoding redox and heat shock proteins in b10H. Collectively, our results indicate that soybeans transformed with HaHB4 are expected to have a reduced seed yield penalty when cultivated in warm and dry conditions, which constitute the best target environments for this technology.

Phenotypic and genotypic characterization of endophytic bacteria associated with transgenic and non-transgenic soybean plants.

Endophytic bacteria isolated from non-transgenic and transgenic Roundup Ready® glyphosate-resistant (GR) soybean plants were investigated to analyze the correspondence between phenotypic and genotypic characteristics and to determine whether or not the strains could be grouped based on the source of isolation in transgenic or non-transgenic plants, respectively. Most of the strains recovered from GR plants have shown the ability for plant growth promotion (PGP) by means of IAA production and inorganic phosphate solubilization, and 100% of the strains showed great motility (swarm or swim); in addition, 90% of the strains were able to metabolize the majority of carbon sources tested. GR soybean fields showed higher endophytes abundance than non-transgenic; however, analyzing the phylogenetic trees constructed using the partial 16SrRNA gene sequences, higher diversity was observed in non-transgenic soybean fields. Overall the majority of isolated endophytes could utilize multiple patterns of carbon sources and express resistance to antibiotics, while isolates varied widely in the PGP ability. The greater pattern and frequency of utilization of carbon sources and frequency and intensity of antibiotic resistance compared with PGP ability within the soybean endophytes community suggest that carbon sources metabolism and antibiotic resistance confer a greater relative fitness benefit than PGP ability. In conclusion, cluster analysis of the phenotypes and 16SrRNA gene sequences reveals lack of correspondence between the pattern of bacterial isolates and the transgenic character of plants, and the heterogeneity of clustering suggested that various adaptive processes, such as stress response, could have contributed to generate phenotypic variability to enhance endophytes overall fitness.

Evaluation of changes in the macro and micronutrients homeostasis of transgenic and non-transgenic soybean plants after cultivation with silver nanoparticles through ionomic approaches.

An ionomic approach is conducted for evaluating the silver distribution, in different soybean plant compartments, as well as its influence on the homeostasis of some macro (P and S) and micro (Cu, Fe, Mn and Zn) nutrients. Silver is added to transgenic and non-transgenic soybean plants as nanoparticles or silver nitrate for comparative purposes. The transgenic plants translocate a higher amount of silver (100 and 65% for silver nanoparticles and silver nitrate expositions, respectively) than non-transgenic, and considering the treatments, the cultivation with silver nanoparticles results in a higher translocation rate (100 and 21% for transgenic and non-transgenic plants, respectively). In addition, significant differences are found (p < 0.05) considering those macro and micronutrients in all plant compartments, mainly in the roots of those treated plants, indicating not only that both silver forms evaluated interfere in the plant metabolism, but also their toxicities.

Impact of long-term cropping of glyphosate-resistant transgenic soybean [Glycine max (L.) Merr.] on soil microbiome.

The transgenic soybean [Glycine max (L.) Merrill] occupies about 80 % of the global area cropped with this legume, the majority comprising the glyphosate-resistant trait (Roundup Ready(®), GR or RR). However, concerns about possible impacts of transgenic crops on soil microbial communities are often raised. We investigated soil chemical, physical and microbiological properties, and grain yields in long-term field trials involving conventional and nearly isogenic RR transgenic genotypes. The trials were performed at two locations in Brazil, with different edaphoclimatic conditions. Large differences in physical, chemical and classic microbiological parameters (microbial biomass of C and N, basal respiration), as well as in grain production were observed between the sites. Some phyla (Proteobacteria, Actinobacteria, Acidobacteria), classes (Alphaproteobacteria, Actinomycetales, Solibacteres) and orders (Rhizobiales, Burkholderiales, Myxococcales, Pseudomonadales), as well as some functional subsystems (clustering-based subsystems, carbohydrates, amino acids and protein metabolism) were, in general, abundant in all treatments. However, bioindicators related to superior soil fertility and physical properties at Londrina were identified, among them a higher ratio of Proteobacteria:Acidobacteria. Regarding the transgene, the metagenomics showed differences in microbial taxonomic and functional abundances, but lower in magnitude than differences observed between the sites. Besides the site-specific differences, Proteobacteria, Firmicutes and Chlorophyta were higher in the transgenic treatment, as well as sequences related to protein metabolism, cell division and cycle. Although confirming effects of the transgenic trait on soil microbiome, no differences were recorded in grain yields, probably due to the buffering capacity associated with the high taxonomic and functional microbial diversity observed in all treatments.

High levels of biological activity of Cry1Ac protein expressed on MON 87701 × MON 89788 soybean against Heliothis virescens (Lepidoptera:Noctuidae).

BACKGROUND: Genetically modified MON 87701 × MON 89788 soybean (Glycine max) that expresses the Cry1Ac and EPSP-synthase proteins is a new Integrated Pest Management (IPM) tool for controlling Heliothis virescens in Brazil. To Support Insect Resistance Management (IRM) programs and understand the value of this event for IPM, we conducted laboratory and field studies to assess the biological activity of Cry1Ac protein expressed on Bt soybean against this insect pest. RESULTS: Heliothis virescens was highly susceptible to purified Cry1Ac protein [LC50 (FL 95%) = 0.026 (0.021-0.033) µg Cry1Ac mL(-1) diet]. In bioassays with freeze-dried MON 87701 × MON 89788 soybean tissue diluted 25 times in an artificial diet, there was 100% mortality of H. virescens. In bioassays with leaf disc, young trifoliate, flower buds, pods and high artificial infestation under greenhouse condition, MON 87701 × MON 89788 soybean showed a high level of control against H. virescens. Moreover, larvae from first through fifth instar were highly susceptible to MON 87701 × MON 89788 soybean. CONCLUSIONS: The MON 87701 × MON 89788 soybean provides an effective alternative in controlling Heliothis virescens and complies with the concept of high-dose for IRM programs.

Chemical compounds related to nutraceutical and industrial qualities of non-transgenic soybean genotypes.

BACKGROUND: Information about the chemical profile of soybean seed is valuable for breeding programs aimed at obtaining value-added products to meet the demands of niche markets. The objective of this study was to determine seed composition of non-transgenic soybean genotypes with specialty characters in different environments of Argentina. RESULTS: Protein and oil contents ranged from 396 to 424 g kg⁻¹ and from 210 to 226 g kg⁻¹, respectively. Oleic and linolenic acid ratio, the general indicator of oil quality, varied from 2.7 to 3.8. The oil contained high levels of total tocopherols (1429-1558 mg kg⁻¹) and the meal exhibited high levels of total isoflavones (2.91-4.62 mg g⁻¹). The biplot showed that oleic, linoleic and linolenic acids, γ-, δ- and total tocopherols, genistin, malonyl daidzin and genistin, acetyl daidzin and glycitin and total isoflavones allowed the greatest discrimination among the genotypes studied. CONCLUSION: Different chemical profiles of each non-transgenic genotype analyzed were established and, therefore, their identity was defined. These results are important for breeders who intend to obtain new genotypes with improved meal and oil quality, as well as for processors and exporters, who could use them directly as raw material for soyfood processing for nutraceutical purposes.

Transgenic and conventional Brazilian soybeans don't cause or prevent preneoplastic colon lesions or oxidative stress in a 90-day in vivo study / Sojas transgênicas e convencionais brasileiras não causam ou previnem lesões pré-neoplásicas ou stress oxidativo em estudo in vivo de 90 dias

OBJECTIVE: The study presents the results of a 90-day safety assessment of rats fed with four varieties of soybeans, BRS 245 RR and BRS Valiosa RR (transgenic), BRS 133 and MG BR46 Conquista (non-transgenic). METHODS: Diets were prepared by incorporating toasted soybean flour to a commercial diet at 1%, 10% or 20% weight In the in vivo experimental the rats' body weight, body weight gain, food consumption, number of aberrant crypt foci, oxidative stress biomarkers, urea and creatinine levels were analyzed and compared between experimental groups, as well as histopathological observations (digestive tract, liver, kidneys). RESULTS: The results indicate that glyphosate-tolerant soy varieties neither induce nor prevent aberrant crypt foci induction, nor do their conventional counterparts. Similarly, none of the four soybean varieties tested induced changes in the digestive tract, liver or kidney. Serum biochemical parameters were also unchanged. CONCLUSION: The consumption of both, conventional and transgenic soybeans, were insufficient to ameliorate dimethylhydrazine-induced oxidative stress.

OBJETIVO: Este estudo apresenta os resultados de um experimento de 90 dias com o objetivo de avaliar a segurança de quatro variedades de grãos de soja: BRS 245 RR e BRS Valiosa RR (transgênicas), BRS 133 e MG BR46 Conquista (não transgênicas). MÉTODOS: As dietas foram preparadas incorporando farinha de grãos de soja à dieta comercial (FRI-LAB Ratos II) a 1%, 10% ou 20% m/m. O peso corpóreo dos animais, o ganho de peso, o consumo de dieta, o número de focos de criptas aberrantes e os níveis de marcadores de estresse oxidativo, de creatinina e de ureia foram comparados entre os grupos experimentais, assim como as observações histopatológicas (trato digestivo, fígado e rins). RESULTADOS: Os resultados indicaram que as variantes glifosato-tolerantes não induziram ou preveniram a indução de focos de criptas aberrantes, assim como suas parentais convencionais. Similarmente, nenhuma das quatro variedades de grãos de soja testadas induziu alterações no trato digestivo, no fígado e nos rins. Os parâmetros bioquímicos do soro permaneceram também inalterados. CONCLUSÃO: Tanto o consumo de grãos de soja convencionais quanto o de transgênicos foram ineficazes para melhorar os níveis de estresse oxidativo induzidos pela dimetilhidrazina.

Root growth and lignification of glyphosate susceptible and resistant soybean at low temperatures / Crescimento e lignificação de raízes de soja convencional e resistente ao glifosato, em baixa temperatura

Low temperature stress affects plant growth, including primary and secondary metabolism. Glyphosateresistant soybean contains a modified DNA, which encodes a different type of secondary metabolism enzyme related to lignin synthesis compared to conventional glyphosate-susceptible cultivars. Thus, this soybean cultivar might respond differently to low temperatures, compared to glyphosate-susceptible cultivars. This work aimed to investigate how decreasing temperatures influence the growth and lignin content of the glyphosate-resistant soybean compared to its susceptible parental cultivars. Three-day-old seedlings were cultivated in nutrient solution at 10, 15, 20, and 25°C (±2°C), using a 12-h photoperiod. After 96 h, taproot growth, fresh and dry biomass, and lignin levels were determined. The results indicate that lower temperatures decreased seedling and root growth in both types of cultivars; however, glyphosate-resistant soybean exhibited greater root length, biomass, and lignin content compared to the glyphosate-susceptible parental cultivar.(AU)

O estresse causado pela baixa temperatura, dentre outras implicações, afeta o crescimento do vegetal assim como o seu metabolismo secundário. Pelo fato da soja RR apresentar variante enzimática de uma das principais vias do metabolismo secundário, ligada à síntese de lignina, pode apresentar comportamento diferenciado, sob baixa temperatura, se comparada com sua linhagem parental. O objetivo deste trabalho foi investigar possíveis diferenças no crescimento e nos conteúdos de lignina nas raízes de soja cultivar transgênica resistente ao glifosato e cultivar parental em resposta a redução de temperatura. Após três dias de germinação das sementes, as plântulas foram mantidas em solução nutritiva, a 10, 15, 20 e 25°C (±2°C), com fotoperíodo de 12 horas. Após 96 horas, foi avaliado o comprimento relativo da raiz primária, biomassa fresca e seca das raízes e os teores de lignina. Os resultados mostram que a baixa temperatura promoveu redução no crescimento das plântulas e raízes. Dentre as cultivares em estudo, a soja transgênica apresentou maior comprimento relativo, biomassas e teores de lignina.(AU)

Root growth and lignification of glyphosate susceptible and resistant soybean at low temperatures / Crescimento e lignificação de raízes de soja convencional e resistente ao glifosato, em baixa temperatura

Low temperature stress affects plant growth, including primary and secondary metabolism. Glyphosateresistant soybean contains a modified DNA, which encodes a different type of secondary metabolism enzyme related to lignin synthesis compared to conventional glyphosate-susceptible cultivars. Thus, this soybean cultivar might respond differently to low temperatures, compared to glyphosate-susceptible cultivars. This work aimed to investigate how decreasing temperatures influence the growth and lignin content of the glyphosate-resistant soybean compared to its susceptible parental cultivars. Three-day-old seedlings were cultivated in nutrient solution at 10, 15, 20, and 25°C (±2°C), using a 12-h photoperiod. After 96 h, taproot growth, fresh and dry biomass, and lignin levels were determined. The results indicate that lower temperatures decreased seedling and root growth in both types of cultivars; however, glyphosate-resistant soybean exhibited greater root length, biomass, and lignin content compared to the glyphosate-susceptible parental cultivar.

O estresse causado pela baixa temperatura, dentre outras implicações, afeta o crescimento do vegetal assim como o seu metabolismo secundário. Pelo fato da soja RR apresentar variante enzimática de uma das principais vias do metabolismo secundário, ligada à síntese de lignina, pode apresentar comportamento diferenciado, sob baixa temperatura, se comparada com sua linhagem parental. O objetivo deste trabalho foi investigar possíveis diferenças no crescimento e nos conteúdos de lignina nas raízes de soja cultivar transgênica resistente ao glifosato e cultivar parental em resposta a redução de temperatura. Após três dias de germinação das sementes, as plântulas foram mantidas em solução nutritiva, a 10, 15, 20 e 25°C (±2°C), com fotoperíodo de 12 horas. Após 96 horas, foi avaliado o comprimento relativo da raiz primária, biomassa fresca e seca das raízes e os teores de lignina. Os resultados mostram que a baixa temperatura promoveu redução no crescimento das plântulas e raízes. Dentre as cultivares em estudo, a soja transgênica apresentou maior comprimento relativo, biomassas e teores de lignina.

Crescimento e lignificação de raízes de soja convencional e resistente ao glifosato, em baixa temperatura / Root growth and lignification of glyphosate susceptible and resistant soybean at low temperatures

O estresse causado pela baixa temperatura, dentre outras implicações, afeta o crescimento do vegetal assim como o seu metabolismo secundário. Pelo fato da soja RR apresentar variante enzimática de uma das principais vias do metabolismo secundário, ligada à síntese de lignina, pode apresentar comportamento diferenciado, sob baixa temperatura, se comparada com sua linhagem parental. O objetivo deste trabalho foi investigar possíveis diferenças no crescimento e nos conteúdos de lignina nas raízes de soja cultivar transgênica resistente ao glifosato e cultivar parental em resposta a redução de temperatura. Após três dias de germinação das sementes, as plântulas foram mantidas em solução nutritiva, a 10, 15, 20 e 25C (±2C), com fotoperíodo de 12 horas. Após 96 horas, foi avaliado o comprimento relativo da raiz primária, biomassa fresca e seca das raízes e os teores de lignina. Os resultados mostram que a baixa temperatura promoveu redução no crescimento das plântulas e raízes. Dentre as cultivares em estudo, a soja transgênica apresentou maior comprimento relativo, biomassas e teores de lignina.

Low temperature stress affects plant growth, including primary and secondary metabolism. Glyphosateresistant soybean contains a modified DNA, which encodes a different type of secondary metabolism enzyme related to lignin synthesis compared to conventional glyphosate-susceptible cultivars. Thus, this soybean cultivar might respond differently to low temperatures, compared to glyphosate-susceptible cultivars. This work aimed to investigate how decreasing temperatures influence the growth and lignin content of the glyphosate-resistant soybean compared to its susceptible parental cultivars. Three-day-old seedlings were cultivated in nutrient solution at 10, 15, 20, and 25C (±2C), using a 12-h photoperiod. After 96 h, taproot growth, fresh and dry biomass, and lignin levels were determined. The results indicate that lower temperatures decreased seedling and root growth in both types of cultivars; however, glyphosate-resistant soybean exhibited greater root length, biomass, and lignin content compared to the glyphosate-susceptible parental cultivar.

Controle de plantas daninhas, biomassa e metabolismo microbiano do solo em função da aplicação de glifosato ou imazetapir na cultura da soja / Weed control, biomass and microbial metabolism of soil depending on the application of glyphosate and imazethapyr on crop soybeans

Estudou-se o controle de plantas daninhas, as variações da biomassa e do metabolismo microbiano do solo em áreas cultivadas com soja geneticamente modificada e não modificada, em função da aplicação dos herbicidas glifosato ou imazetapir. Testaram-se cultivares de soja (BRS 244RR, geneticamente modificada e BRS 154, não modificada) e herbicidas (glifosato e imazetapir), e tratamento controle com capina. Como variáveis foram avaliadas a fitotoxicidade à cultura, controle de Raphanus raphanistrum(nabo), Digitaria sp. (milhã) e Brachiaria plantaginea (papuã), teores de carbono orgânico total (COT), carbono da biomassa microbiana (CBM), respiração basal (RB) e quociente metabólico (QCO2). O herbicida glifosato, aplicado em dose única ou seqüencial, controla eficientemente as plantas daninhas nabo, milhã e papuã, e aumenta a atividade microbiana, a taxa de respiração basal e o quociente metabólico. O metabolismo microbiano do solo não foi afetado pelo genótipo, geneticamente modificado ou não, mas sim pelo uso do herbicida glifosato.

Studied the weed control and the changes of biomass and microbial soil properties at crop cultivated both genetically modified and non altered soybeans because of glyphosate or imazethapyr herbicide applications. Soybean cultivations were tested (BRS 244RR), genetically modified and BRS 154, non modified) and herbicides (glyphosate and imazethapyr), and control treatment with weed. Variables were evaluated for phytotoxicity to the crop, control of Raphanus raphanistrum (wild radish), Digitaria sp. (crabgrass) and Brachiaria plantaginea (alexsandregrass), total organic carbon (TOC), microbial biomass carbon (MBC), basal respiration (BR) and metabolic quocient (QCO2). The herbicide glyphosate, applied as a single dose or sequentially, effectively controls the weeds wild radish, crabgrass and alexsandregrass and increases microbial activity, basal respiration and metabolic quocient. The microbial metabolism was not affected by the fact that the genotype or not genetically modified, but the use of the herbicide glyphosate.

Weed control, biomass and microbial metabolism of soil depending on the application of glyphosate and imazethapyr on crop soybeans / Controle de plantas daninhas, biomassa e metabolismo microbiano do solo em função da aplicação de glifosato ou imazetapir na cultura da soja

Studied the weed control and the changes of biomass and microbial soil properties at crop cultivated both genetically modified and non altered soybeans because of glyphosate or imazethapyr herbicide applications. Soybean cultivations were tested (BRS 244RR), genetically modified and BRS 154, non modified) and herbicides (glyphosate and imazethapyr), and control treatment with weed. Variables were evaluated for phytotoxicity to the crop, control of Raphanus raphanistrum (wild radish), Digitaria sp. (crabgrass) and Brachiaria plantaginea (alexsandregrass), total organic carbon (TOC), microbial biomass carbon (MBC), basal respiration (BR) and metabolic quocient (QCO2). The herbicide glyphosate, applied as a single dose or sequentially, effectively controls the weeds wild radish, crabgrass and alexsandregrass and increases microbial activity, basal respiration and metabolic quocient. The microbial metabolism was not affected by the fact that the genotype or not genetically modified, but the use of the herbicide glyphosate.

Estudou-se o controle de plantas daninhas, as variações da biomassa e do metabolismo microbiano do solo em áreas cultivadas com soja geneticamente modificada e não modificada, em função da aplicação dos herbicidas glifosato ou imazetapir. Testaram-se cultivares de soja (BRS 244RR, geneticamente modificada e BRS 154, não modificada) e herbicidas (glifosato e imazetapir), e tratamento controle com capina. Como variáveis foram avaliadas a fitotoxicidade à cultura, controle de Raphanus raphanistrum (nabo), Digitaria sp. (milhã) e Brachiaria plantaginea (papuã), teores de carbono orgânico total (COT), carbono da biomassa microbiana (CBM), respiração basal (RB) e quociente metabólico (QCO2). O herbicida glifosato, aplicado em dose única ou seqüencial, controla eficientemente as plantas daninhas nabo, milhã e papuã, e aumenta a atividade microbiana, a taxa de respiração basal e o quociente metabólico. O metabolismo microbiano do solo não foi afetado pelo genótipo, geneticamente modificado ou não, mas sim pelo uso do herbicida glifosato.

Produtividade de grãos da soja em função do manejo de herbicida e fungicidas / Soybean grain yield in response to herbicide and fungicides

Com a introdução da soja resistente ao glifosato, ocorreu mudança no manejo da cultura, principalmente com relação ao manejo das plantas invasoras. Este trabalho foi desenvolvido com o objetivo de avaliar os efeitos da aplicação de diferentes manejos de herbicidas e fungicidas sobre o rendimento de grãos e os componentes do rendimento da soja. O experimento foi conduzido no ano agrícola 2006/2007, na área experimental do Departamento de Fitotecnia da Universidade Federal de Santa Maria. Foram utilizadas quatro cultivares de soja Roundup ReadyTM ('NK Mireya 4.2 RR', 'Fundacep 55 RR', 'NK Mágica 7.3 RR' e 'A 8100 RG'), dois manejos de herbicida (Clethodim + Bentazon e outro com glifosato), dois manejos de doenças constituídos com a aplicação de fungicida (Tebuconazole + Tiofanato Metílico) e sem o tratamento. O delineamento experimental utilizado foi o de blocos ao acaso com parcela subsubdivididas, com quatro repetições. Foram avaliados o rendimento de grãos e os componentes do rendimento. As cultivares responderam diferentemente ao manejo de herbicidas e fungicidas para produção de grãos; as cultivares que foram afetadas pelo manejo de herbicida obtiveram maior produtividade com a aplicação de glifosato, efeito que também foi observado com a aplicação de fungicida. As cultivares mais e menos produtivas apresentaram o maior e o menor peso de grãos, respectivamente. A aplicação de fungicida aumentou o índice de colheita.

With the introduction of the resistant soybeans to the glyphosate changed the management of the culture, mainly for management of the weed. This work was developed with the objective of evaluate the effect of the different management systems of herbicides and fungicides in grain yield and yield components of the soybean. The experiment was carried in the agricultural year of 2006/2007, at the Experimental Area of Department of Phytotecny of the Santa Maria Federal University. It was used, four soybean cultivars Roundup ReadyTM ('NK Mireya 4.2 RR', 'Fundacep 55 RR', 'NK Mágica 7.3 RR' and 'A 8100 RG'), two herbicide management (Clethodim + Bentazon and with glyphosate) and two fungicides management with application (Tebuconazole + Tiofanato Metílico) and without treatment. The experiment design was randomized blocks with splitsplitplot plot, with four replications. It was evaluated the grain yield and components of yield. The cultivars showed different responses to the management of herbicide and fungicides, for grain yield, cultivars that were affected by the herbicide management showed higher productivity with the application of glyphosate. The effect also was observed with the application of fungicide. The cultivars more and less productive presented the highest and lowest grain weight respectively. Fungicide application increased the harvest index.

Transformação genética e aplicação de glifosato na microbiota do solo, fixação biológica de nitrogênio, qualidade e segurança de grãos de soja geneticamente modificada / Genetic transformation and the use glyphosate on soil microbial, biological nitrogen fixation, quality and safety of genetically modified soybean

A soja geneticamente modificada resistente ao herbicida glifosato (GM RR) é o principal produto da biotecnologia vegetal, considerando-se a evolução da área cultivada e o consumo desse grão. Os Estados Unidos, a Argentina e o Brasil são os maiores produtores de soja GM RR. A liberação para cultivo da soja GM RR no Brasil foi efetivada com base, quase que exclusivamente, em trabalhos realizados em outros países, sem a devida validação nas condições edafoclimáticas locais. Nesse contexto, buscou-se coletar e analisar os principais trabalhos que versam sobre impacto ambiental, metabolismo da planta, qualidade e segurança da soja GM RR tratada e não tratada com glifosato. De modo geral, os trabalhos analisados apresentam algumas características comuns: a) avaliam poucas variáveis; e b) inferem, a partir de simulação com ensaios em casa de vegetação ou in vitro, possíveis respostas no cultivo comercial. Embora ainda escassos, os estudos realizados apontam para o fato de que a transformação genética não afeta os microrganismos do solo, nem a fixação biológica de nitrogênio, nem a composição dos grãos. O fator que pode afetar essas variáveis é a aplicação do glifosato no controle de plantas daninhas, ou seja, os riscos de perigo ao ambiente e à segurança dos produtos derivados dessa matéria-prima se devem ao insumo aplicado durante o cultivo, e não à transformação genética propriamente dita.

The genetically modified soybean resistant to glyphosate (GM RR) is the main product of plant biotechnology, considering the evolution of the area cultivated and the use of this grain. EUA, Argentina and Brazil are the largest producers of GM RR. The release of GM RR soybean cultivation in Brazil was done based on researches that were accomplished in other countries without the validation of the same edaphoclimatic conditions. In this context, the main researches about environmental impact, plant metabolism, quality and safety of GM RR soybean with or without glyphosate application were collected and investigated. In general, the researches investigated showed some similar characteristics: a) few variables were studied; b) simulations in green house or in vitro are used to infer possible response on the field. Although scarce, the researches denoted that the genetic transformation did not affect soil microorganisms, biological nitrogen fixation and composition of grains. The factor which could affect these variables is the glyphosate application in weed control, thus the risk of damage to the environment and the safety of products derived from this raw materialare due to the use of the herbicide during cultivation, and not to the genetic transformation. Key words: Transgenic soybean, soil microorganisms, herbicides residue, isoflavones.

Produtividade de grãos da soja em função do manejo de herbicida e fungicidas

With the introduction of the resistant soybeans to the glyphosate changed the management of the culture, mainly for management of the weed. This work was developed with the objective of evaluate the effect of the different management systems of herbicides and fungicides in grain yield and yield components of the soybean. The experiment was carried in the agricultural year of 2006/2007, at the Experimental Area of Department of Phytotecny of the Santa Maria Federal University. It was used, four soybean cultivars Roundup ReadyTM ('NK Mireya 4.2 RR', 'Fundacep 55 RR', 'NK Mágica 7.3 RR' and 'A 8100 RG'), two herbicide management (Clethodim + Bentazon and with glyphosate) and two fungicides management with application (Tebuconazole + Tiofanato Metílico) and without treatment. The experiment design was randomized blocks with splitsplitplot plot, with four replications. It was evaluated the grain yield and components of yield. The cultivars showed different responses to the management of herbicide and fungicides, for grain yield, cultivars that were affected by the herbicide management showed higher productivity with the application of glyphosate. The effect also was observed with the application of fungicide. The cultivars more and less productive presented the highest and lowest grain weight respectively. Fungicide application increased the harvest index.

Com a introdução da soja resistente ao glifosato, ocorreu mudança no manejo da cultura, principalmente com relação ao manejo das plantas invasoras. Este trabalho foi desenvolvido com o objetivo de avaliar os efeitos da aplicação de diferentes manejos de herbicidas e fungicidas sobre o rendimento de grãos e os componentes do rendimento da soja. O experimento foi conduzido no ano agrícola 2006/2007, na área experimental do Departamento de Fitotecnia da Universidade Federal de Santa Maria. Foram utilizadas quatro cultivares de soja Roundup ReadyTM ('NK Mireya 4.2 RR', 'Fundacep 55 RR', 'NK Mágica 7.3 RR' e 'A 8100 RG'), dois manejos de herbicida (Clethodim + Bentazon e outro com glifosato), dois manejos de doenças constituídos com a aplicação de fungicida (Tebuconazole + Tiofanato Metílico) e sem o tratamento. O delineamento experimental utilizado foi o de blocos ao acaso com parcela subsubdivididas, com quatro repetições. Foram avaliados o rendimento de grãos e os componentes do rendimento. As cultivares responderam diferentemente ao manejo de herbicidas e fungicidas para produção de grãos; as cultivares que foram afetadas pelo manejo de herbicida obtiveram maior produtividade com a aplicação de glifosato, efeito que também foi observado com a aplicação de fungicida. As cultivares mais e menos produtivas apresentaram o maior e o menor peso de grãos, respectivamente. A aplicação de fungicida aumentou o índice de colheita.

Produtividade de grãos da soja em função do manejo de herbicida e fungicidas

With the introduction of the resistant soybeans to the glyphosate changed the management of the culture, mainly for management of the weed. This work was developed with the objective of evaluate the effect of the different management systems of herbicides and fungicides in grain yield and yield components of the soybean. The experiment was carried in the agricultural year of 2006/2007, at the Experimental Area of Department of Phytotecny of the Santa Maria Federal University. It was used, four soybean cultivars Roundup ReadyTM ('NK Mireya 4.2 RR', 'Fundacep 55 RR', 'NK Mágica 7.3 RR' and 'A 8100 RG'), two herbicide management (Clethodim + Bentazon and with glyphosate) and two fungicides management with application (Tebuconazole + Tiofanato Metílico) and without treatment. The experiment design was randomized blocks with splitsplitplot plot, with four replications. It was evaluated the grain yield and components of yield. The cultivars showed different responses to the management of herbicide and fungicides, for grain yield, cultivars that were affected by the herbicide management showed higher productivity with the application of glyphosate. The effect also was observed with the application of fungicide. The cultivars more and less productive presented the highest and lowest grain weight respectively. Fungicide application increased the harvest index.

Com a introdução da soja resistente ao glifosato, ocorreu mudança no manejo da cultura, principalmente com relação ao manejo das plantas invasoras. Este trabalho foi desenvolvido com o objetivo de avaliar os efeitos da aplicação de diferentes manejos de herbicidas e fungicidas sobre o rendimento de grãos e os componentes do rendimento da soja. O experimento foi conduzido no ano agrícola 2006/2007, na área experimental do Departamento de Fitotecnia da Universidade Federal de Santa Maria. Foram utilizadas quatro cultivares de soja Roundup ReadyTM ('NK Mireya 4.2 RR', 'Fundacep 55 RR', 'NK Mágica 7.3 RR' e 'A 8100 RG'), dois manejos de herbicida (Clethodim + Bentazon e outro com glifosato), dois manejos de doenças constituídos com a aplicação de fungicida (Tebuconazole + Tiofanato Metílico) e sem o tratamento. O delineamento experimental utilizado foi o de blocos ao acaso com parcela subsubdivididas, com quatro repetições. Foram avaliados o rendimento de grãos e os componentes do rendimento. As cultivares responderam diferentemente ao manejo de herbicidas e fungicidas para produção de grãos; as cultivares que foram afetadas pelo manejo de herbicida obtiveram maior produtividade com a aplicação de glifosato, efeito que também foi observado com a aplicação de fungicida. As cultivares mais e menos produtivas apresentaram o maior e o menor peso de grãos, respectivamente. A aplicação de fungicida aumentou o índice de colheita.

Transformação genética e aplicação de glifosato na microbiota do solo, fixação biológica de nitrogênio, qualidade e segurança de grãos de soja geneticamente modificada

The genetically modified soybean resistant to glyphosate (GM RR) is the main product of plant biotechnology, considering the evolution of the area cultivated and the use of this grain. EUA, Argentina and Brazil are the largest producers of GM RR. The release of GM RR soybean cultivation in Brazil was done based on researches that were accomplished in other countries without the validation of the same edaphoclimatic conditions. In this context, the main researches about environmental impact, plant metabolism, quality and safety of GM RR soybean with or without glyphosate application were collected and investigated. In general, the researches investigated showed some similar characteristics: a) few variables were studied; b) simulations in green house or in vitro are used to infer possible response on the field. Although scarce, the researches denoted that the genetic transformation did not affect soil microorganisms, biological nitrogen fixation and composition of grains. The factor which could affect these variables is the glyphosate application in weed control, thus the risk of damage to the environment and the safety of products derived from this raw materialare due to the use of the herbicide during cultivation, and not to the genetic transformation. Key words: Transgenic soybean, soil microorganisms, herbicides residue, isoflavones.

A soja geneticamente modificada resistente ao herbicida glifosato (GM RR) é o principal produto da biotecnologia vegetal, considerando-se a evolução da área cultivada e o consumo desse grão. Os Estados Unidos, a Argentina e o Brasil são os maiores produtores de soja GM RR. A liberação para cultivo da soja GM RR no Brasil foi efetivada com base, quase que exclusivamente, em trabalhos realizados em outros países, sem a devida validação nas condições edafoclimáticas locais. Nesse contexto, buscou-se coletar e analisar os principais trabalhos que versam sobre impacto ambiental, metabolismo da planta, qualidade e segurança da soja GM RR tratada e não tratada com glifosato. De modo geral, os trabalhos analisados apresentam algumas características comuns: a) avaliam poucas variáveis; e b) inferem, a partir de simulação com ensaios em casa de vegetação ou in vitro, possíveis respostas no cultivo comercial. Embora ainda escassos, os estudos realizados apontam para o fato de que a transformação genética não afeta os microrganismos do solo, nem a fixação biológica de nitrogênio, nem a composição dos grãos. O fator que pode afetar essas variáveis é a aplicação do glifosato no controle de plantas daninhas, ou seja, os riscos de perigo ao ambiente e à segurança dos produtos derivados dessa matéria-prima se devem ao insumo aplicado durante o cultivo, e não à transformação genética propriamente dita.