Spectral responses at visible and near-infrared wavelengths of soybean plants to fungicides / Respostas espectrais em comprimentos de onda visível e infravermelho-próximo de plantas de soja a fungicidas

The study evaluated the efficacy and soybean spectral responses to fifteen foliar fungicide mixtures labeled to control Asian soybean rust. Canopy level reflectance was measured using a multispectral camera onboard a multirotor drone before and two hours after each spray. The third application of fungicides improved control of soybean rust and increased yield. Nevertheless, up to three consecutive foliar fungicides applications did not affect the reflectance of soybean plants at visible and infrared wavelengths. Thus, drones can be a viable strategy for data acquisition regardless of the application of the fungicides.

Esse estudo avaliou a eficácia e as respostas espectrais de plantas de soja a quinze misturas de fungicidas utilizados no controle da ferrugem asiática da soja (FAS). A refletância do nível do dossel foi medida usando uma câmera multiespectral a bordo de um drone multirotor antes e duas horas após cada pulverização. A terceira aplicação de fungicidas melhorou o controle de FAS e aumentou a produtividade. Porém, três aplicações foliares consecutivas de fungicidas não afetaram a refletância de plantas de soja nos comprimentos de onda visível e infravermelho. Assim, drones podem ser uma estratégia viável para aquisição de dados independentemente da aplicação de fungicidas.

The Effect of Ferrous Nano-oxide Particles on Physiological Traits and Nutritional Compounds of Soybean ( Glycine max L) Seed

ABSTRACT Soybean (Glycine max L.) seed contains amounts of protein, lipid, carbohydrate and mineral elements, which protein and lipid have been known as a main part for soybean's trade value. In this study, in order to investigate the effect of ferrous nano-oxide particles on nutritional compounds of soybean seed, an experiment with 5 treatments and 3 replications was conducted as a randomized complete block design. Treatments were 5 concentrations of ferrous nano-oxide particles including 0, 0.25, 0.5, 0.75 and 1 g L-1 which were sprayed 3 times at 4 and 8 leaves stage and pod initiation. Lipid and protein contents, fatty acids profile, some of mineral elements such as Fe, Mg, Ca and P, chlorophyll a, b and total chlorophyll content were determined. Results showed that solution containing ferrous nano-oxide particles had significant effect on nutritional compounds of soybean seed (P<0.01) compared to control. The highest content of lipid and protein (25.4 and %33.8, respectively) observed by applying 0.75 g L-1 of ferrous nano-oxide and the lowest content was also in control. Changes in the trends of fatty acids profile (palmitic, oleic, linoleic and linolenic acids), some of mineral elements (Fe, Mg, Ca and P) and chlorophyll contents were similar to lipid and protein levels which by increasing in concentration of ferrous nano-oxide from 0 to 0.75 g L-1 all measured parameters also increased, but reduction in all parameters was observed in concentration from 0.75 to 1 g L-1. In conclusion, application of 0.75 to 1 g L-1 ferrous nano-oxide had the best effect on the nutrient composition of soybean seed.

Incorporation of Na+/H+ antiporter gene from Aeluropus littoralis confers salt tolerance in soybean (Glycine max L.).

To develop a salt-tolerant soybean (Glycine max L.) cultivar, a minimal linear Na+/H+ antiporter gene cassette (35S CaMV promoter, open-reading-frame of AlNHX1 from Aeluropus littoralis and NOS terminator) was successfully expressed in soybean cultivar TF-29. Southern and Northern blot analysis showed that AlNHX1 was successfully incorporated into the genome and expressed in the transgenic plants. The AlNHX1 transgenic plant lines exhibited improved growth in severe saline condition (150 mM NaCl). The transgenic lines accumulated a lower level of Na+ and a higher level of K+ in the leaves than wild-type plants under saline condition (150 mM NaCl). Observations on the chlorophyll content, photosynthetic rates, malondialdehyde and relative electrical conductivity indicated that transgenic plants exhibited tolerance to salt stress, growing normally at salt concentrations up to 150 mM. These results demonstrated that AlNHX1 was successfully transferred into soybean and the salt-tolerance was improved by the overexpression of AlNHX1.

Assessment of somatic embryogenesis potency in Indian soybean [Glycine max (L.) Merr.] cultivars.

Majority of the Indian soybean cultivars are recalcitrant to tissue culture regeneration. The present communication reports the development of somatic embryogenesis in a liquid culture medium from immature cotyledons of G. max. Following induction with 2,4-dichlorophenoxyacetic acid (2,4-D) or naphthalene acetic acid (NAA), the number of somatic embryos and percentage of explants that responded were higher with 45.24 µM 2,4-D. The proliferation of somatic embryos for three successive cycles was achieved in 22.62 µM 2,4-D. Histodifferentiation of somatic embryos under NAA (10.74 µM) indicated that better embryo development and maturation was achieved without any growth regulator. The amino acids such as L-glutamine favoured the somatic embryo induction and histodifferentiation at 20 and 30 mM respectively, where as L-asparagine at 10 mM concentration enhanced the somatic embryo proliferation. In addition, somatic embryos that were desiccated (air-drying method) for 5 days showed better germination (40.88%). The Indian soybean cultivars also showed strict genotypic influence and cv. Pusa 16 was emerged as a best responding cultivar for somatic embryo induction with 74.42% of response.

Silicon influence on resistance induction against Bemisia tabaci biotype B (Genn.) (Hemiptera: Aleyrodidae) and on vegetative development in two soybean cultivars

The potential of populations of Bemisia tabaci (Genn.) to become resistant to insecticides has stimulated research into alternative tactics of integrated pest management such as the induction of host-plant resistance. Recent data have shown that silicon can increase the degree of resistance of host plants to insect pests. Therefore the aim of our work was to study the effects of silicon application on the vegetative development of soybean plants and on the induction of resistance to the silverleaf whitefly, B. tabaci biotype B. We performed choice and no-choice tests of oviposition preference on two soybean cultivars, IAC-19 (moderately resistant to B. tabaci biotype B) and MONSOY-8001 (susceptible), with and without application of silicon. Silicon did not affect silverleaf whitefly oviposition preferences, but caused significant mortality in nymphs. Thus, silicon increased the degree of resistance to silverleaf whitefly. Silicon decreased the production of phenolic compounds, but did not affect lignin production. However, when applied to cultivar IAC-19, it increased the production of non-protein organic nitrogen. Silicon had no effect on the vegetative development of soybean plants, but it increased the degree of resistance to the silverleaf whitefly. We conclude that silicon applications combined with cultivar IAC-19 can significantly decrease silverleaf whitefly populations, having a positive impact both on the soybean plant and on the environment.

Indução de fitoalexinas em soja e sorgo por preparações de Saccharomyces boulardii / Induction of phytoalexins in soybean and sorghum by Saccharomyces boulardii

O gênero Saccharomyces tem sido usado como indutor de resistência ou para controle biológico em muitos patossistemas. Neste trabalho objetivou-se a indução de fitoalexinas em mesocótilos de sorgo e cotilédones de soja pela levedura Saccharomyces boulardii na forma do produto comercial Floratil (Merck) (com 2 x 106 células/mg produto comercial - pc) e massa de células obtidas de meio líquido YEPG (primeiramente com 14 dias de cultivo e, posteriormente, com 7, 14, 21, 28 e 35 dias) ambos em concentrações de 0,005; 0,05; 0,5; 5; 15 e 25 mg/mL, além de filtrado desse meio nas concentrações de 0,01; 0,1; 1; 5; 10 e 20%. Como tratamentos controle utilizou-se água e S. cerevisiae (25 mg/mL de pc) para soja e água e acibenzolar-S-metil (ASM) (125 mg i.a./L) para sorgo. Em soja os três produtos apresentaram efeito dose-dependente, com ajustes de equações de 1° grau e R2 de 0,64; 0,94 e 0,98 não tendo efeito do tempo de cultivo da levedura na indução de fitoalexinas. Em sorgo apenas o filtrado e Floratil tiveram efeito dose-dependente com equação de 1° grau e R2 de 0,63 e 0,94 respectivamente e obteve-se nos diferentes dias de cultivo R2 de 0,62 com a massa de células somente. Portanto, pode-se evidenciar o potencial indutor de fitoalexinas dos produtos a base de S. boulardii para ensaios com indução de resistência em patossistemas envolvendo sorgo e soja.

Saccharomyces yeast compounds have been used as a resistance elicitor or for biological control in many pathosystems. Thus, the aim of this research was to verify the induction of phytoalexins in sorghum mesocotyls and soybean cotyledons by using Saccharomyces boulardii in the form of the commercial product Floratil (Merck) (with 2 x 106 cells/mg) and yeast-cell mass obtained from liquid culture in YEPG medium (with 7, 14, 21, 28 and 35 days old), both at concentrations of 0.005, 0.05, 0.5, 5, 15 and 25 mg/mL, as well as the filtrate of this medium in concentrations of 0.01, 0.1, 1, 5, 10 and 20%. The control treatments consisted of distilled water and S. cerevisiae (25 mg of commercial product per mL) for the soybean tests and distilled water and acibenzolar-S-methyl (125 mg of active ingredient per L) for the sorghum tests. In soybeans the three tested S. boulardii products presented a dose-dependent effect with R2 of 0.64, 0.94 and 0.98 for the culture filtrate, cell suspension and commercial product of S. boulardii, respectively, with no effect of culture time of yeasts on phytoalexin induction. In sorghum, only the culture filtrate and Floratil presented a dose-dependent effect, with R2 of 0.63 and 0.94, respectively, and the cell suspension of S. boulardii showed dependence of culture time with R2 of 0.62. Thus, S. boulardii and its derivates induce phytoalexins and have potential to be used as an elicitor for assays with induction resistance in pathosystems involving sorghum and soybean plants.

Efeito do déficit hídrico em características químicas e bioquímicas da soja e na degradação da clorofila, com ênfase na formação de metabólitos incolores / Influence of drought stress on chemical and biochemical characteristics of soybean and on chlorophyll degradation, with focus on the formation of non-coloured chlorophyll catabolites

O Brasil é o segundo maior produtor e exportador de soja (Glycine max L. Merrill) no mundo. A produção é altamente dependente de fatores climáticos, incluindo a temperatura e quantidade de chuva. A soja cultivada no sul do país em 2005 sofreu déficit hídrico causado por temperaturas altas acompanhado por umidade baixa durante o estádio reprodutivo. Pouco se sabe sobre a influência do déficit hídrico na degradação da clorofila e na qualidade dos grãos em geral. Nesse trabalho foram analisadas, numa primeira etapa, as características químicas e bioquímicas de cinco amostras de soja, provenientes de três cultivares que cresceram sob déficit hídrico e que não atendiam aos padrões para comercialização por conter altas quantidades de sementes verdes. Os grãos foram analisados quanto a diversos parâmetros físico-químicos e bioquímicos incluindo a análise dos pigmentos verdes imediatamente após a colheita e após 20 meses de armazenamento. A acidez foi medida adicionalmente após 30 meses de armazenamento. A atividade de água e umidade foram 0,6-0,7 e 8,7 %-11,9 %, respectivamente, e não mudaram durante a estocagem, mas houve um aumento em acidez o que indica atividade de lipases. A atividade da lipoxigenase 1 foi significativamente prejudicada. Imediatamente após a colheita os pigmentos verdes correspondiam a feofitina a, feofitina b e pequenas quantidades de clorofila a e b, e traços de outros derivados da clorofila, em ordem decrescente. Após 20 meses de estocagem quase todos os pigmentos haviam desaparecido. O déficit hídrico provavelmente aumentou a permeabilidade das membranas, o que levou a um aumento do pH e promoveu a transformação das clorofilas para feofitinas. Na segunda etapa do trabalho foi estudado o estágio avançado da degradação natural da clorofila na qual desaparece a coloração esverdeada dos grãos. Esta etapa corresponde à formação de catabólitos incolores (NCC), mas existem controvérsias se essas substâncias são os produtos finais da degradação...

Brazil is the second largest soybean (Glycine max L. Merrill) producer and exporter in the world. The production depends on climatic factors, like temperature and rain volume. Soybeans cultivated in the south of the country in 2005 suffered drought stress imposed by adverse high ambient temperature, accompanied by low humidity during the reproductive stage. Little information is available regarding drought stress on quality of grains. In this study, firstly, chemical and biochemical characteristics of five soybean samples belonging to three cultivars grown under drought stress and did not meet standards for marketing due to high amounts of green seeds, were evaluated. Grains were analyzed for several physicochemical ad biochemical parameters, including analysis of pigment contents, immediately after harvest and after 20 months of storage at room temperature. Acidity was measured additionally after 30 month of storage. Water activity and humidity were 0.6 - 0.7 and 8.7 % - 11.9 %, respectively, and did not change during storage time, but there was an increase in acidity, which alludes to lipase activity. The activity of lipoxygenase 1 was significantly prejudiced. Immediately after harvest, green pigments corresponded mainly to pheophytin a, followed by pheophytin b, small quantities of chlorophyll b and chlorophyll a and traces of other chlorophyll derivatives. After 20 months of storage almost all green pigments had disappeared. Drought stress probably enhanced membrane permeability, which led to a lower pH and promoted transformation of chlorophylls to pheophytins. In the second part of the study, the advanced stage of natural chlorophyll degradation was investigated, in which the green colour of the seeds disappears. This stage corresponds to the formation of non-coloured chlorophyll catabolites (NCC), but there are controversies if those are the final products. Thus, the formation and degradation of NCC during soybean (Glycine max L. Merrill)...

Phage typing of indigenous soybean-rhizobia and relationship of a phage group strains for their asymbiotic and symbiotic nitrogen fixation.

A total of 354 indigenous bradyrhizobia were isolated from soybean nodules collected from five major crop grown regions. Host-specific 12 phages, each active on particular strains were selected. Factors, which influence the interaction between the host and phage, were examined. Four different types of plaques were detected. Nearly 17% of isolates were found resistant to all phages. Phage sensitivity patterns revealed a total of 32 distinct phage genotype groups. Different set of phage combinations expressed variation in specificity for parasitizing against particular group of rhizobia. Distributions of isolates in each phage types differed markedly between regions. Interestingly, nine strains belonging to phage group 16 exhibited high ex planta nitrogenase activity in culture. However, no correlation could be established between high ex planta nitrogenase activity and their symbiotic effectiveness with soybean cultivars. Soybean cv. JS335 showed relatively superior performance than Bragg and Lee with indigenous bradyrhizobial strains. Phage typing revealed the existence of large genetic diversity among native rhizobia and selection of the superior bradyrhizobial strains can also be possible for a given soil-climate-cultivar complex.

A male-sterile mutation in soybean (Glycine max) affecting chromosome arrangement in metaphase plate and cytokinesis

A spontaneous male-sterile, female-fertile mutation affecting bivalent arrangement at the metaphase plate and cytokinesis was detected in line BR98-197 of the soybean breeding program developed by Embrapa - National Soybean Research Centre. Untill diakinesis, meiosis was normal with chromosome pairing as bivalents. From this phase, in several meiocytes, bivalents were not able to organize a single metaphase plate and remained scattered in the cytoplasm in a few or several groups. In these meiocytes, chromosomes segregated in both divisions giving rise to several micronuc1ei. However, the main cause of male sterility was the absence of cytokinesis after telophase II. Instead of the typical tetrads of microspores, four nucleate coenocytic microspores were formed. In the mutant, pollen mitoses did not occur, and after engorgement by starch, pollen underwent a progressive process of degeneration

Interactions between VA mycorrhizal fungus glomus mosseae, bradyrhizobium japonicum and pseudomonas syringae in soybean plants

The interactions between VA mycorrhizal fungus Glomus mosseae, the pathogenic bacterium Pseudomonas syringae, in the presence or absence of Bradyrhizobium japonicum on some physiological parameters of soybean plants were investigated. The results revealed that co- inoculation of G. mosseae with B. japonicum increased the shoot dry weight, nodulation, accumulated nitrogen and phosphorus as well as nitrate reductase activity in soybean plants. G. mosseae prevented P. syringae from infecting soybean plants and improved the plants growth. Nitrogen and phosphorus accumulation and nitrate reductase activity. The presence of the mycorrhizal fungus suppressed the population density of the pathogenic bacterium in the rhizosphere of soybean plants. The mycorrhiza increased the plant resistance to P. syringae more prominently in the presence of B. japonicum

Biochemical and physiological aspects of soybean seeds under the effect of benzyl adenine

Two pot experiments were performed in two successive years [1990, 1991] to study the effect of foliar application of benzyl adenine [at 50, 100 and 200 ppm] at flowering and fruiting stages on carbohydrate, protein, oil of the soybean seeds yielded. The results revealed that benzyl adenine at the lowest concentration [50 ppm] induced a marked increase in the carbohydrate content whereas the relatively high concentrations [100 and 200 ppm] induced a marked decrease in the carbohydrate content. The protein content of soybean seeds was increased significantly in response to all doses of benzyl adenine. Also, the results showed that benzyl adenine induced marked changes in amino acid composition of soybean seed protein were dependent upon the concentration of benzyl adenine. Treatment with benzyl adenine at different concentrations induced an appreciable increase in the total saturated fatty acids of soybean oil relative to unsaturated ones and to the control values