Biometria e qualidade fisiológica de sementes de diferentes matrizes de Tabebuia chrysotricha (Mart. Ex A. DC.) Stand I.

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Deficiências de macronutrientes em plantas de soja cv. BRSMG 68 (Vencedora) cultivada em solução nutritive

Soybean is a crop of great importance for Brazil, and knowledge of their nutritional status allows production and high quality products. Thus, the present work aimed to evaluate the culture of the soybean cv. BRSMG 68 (Vencedora), submitted to macronutrients omission on the development, nutritional status and the visual symptomatology of nutrient deficiency. The design used was completely randomized, with seven treatments that corresponded to the complete (macro and micronutrients) solution and the individual omission of N, P, K, Ca, Mg and S. The treatments were applied two weeks after the emergency of the soybean. The nutrient solution was constantly oxygenated and replaced weekly, and the pH monitored daily remained around 5. After six weeks of application of the treatments, the height of the plants, number of leaves, stem diameter was evaluated, matter dry accumulated in the roots, it leaves aerial and the nutritional state and the characterization of the visual symptoms. The macronutrient deficiency promoted a decrease in production of root and shoot dry mass of soybean cultivar BRSMG 68 (Vencedora) in nutrient solution, for the full treatment. The most limiting nutrient for dry matter production of soybean compared to complete treatment were N, S and K, with decreases of 90, 76 and 73%, respectively. Individual omissions resulted in morphological changes, which were translated by characteristic visual symptoms of nutritional deficiency of the respective nutrient.

Influência da cobertura de aveia-preta e milheto sobre comunidade de plantas daninhas e produção de soja

The success in weed control by using straw depends on the management time, straw quality and quantity. The objective of this research was to evaluate the suppressor effect of black-oats and millet straw cover on the incidence of weeds and on the productivity of the soybean crop. The experiment was carried out during the years 2006 and 2007, in an area from the Farm of Education, Research and Production of FCAV-UNESP, Jaboticabal Campus, in a completely randomized block design, with four replications. Treatments consisted of different types of black oats and pearl millet straw management before soybean seeding (without management, obtained by machine cut, desiccated using glyphosate desiccation and with paraquat) and different periods of straw deposition (0, 15, 30 e 60 days before soybean seeding). The weed population and the characteristics of soybean growth and production were evaluated. The deposition of black oats and pearl millet straw provided reductions in weed density and dry mass, and this effect was more effective when the deposition occurred until 15 days prior to soybean seeding. The suppressor effect of black oats straw was more pronounced than that of pearl millet straw, regardless of the drying method, although the millet had a greater dry matter production. No significant differences were found between the drying methods and the straw effectiveness.

Variabilidade dos atributos de um latossolo vermelho sob plantio direto no cerrado brasileiro e produtividade da soja

The spatial variability of several soil attributes (bulk density, penetration resistance, water content, organic matter content and pH) as well as soybean yield have been assessed during the 2007/08 growing season, in Selviria (MS) in a Hapludox (Typic Acrustox), under no tillage. The objectives were to assess the spatial variability of soil and plant parameters at the small plot scale and to select the best soil attribute explaining most the variability of agricultural productivity. Soil and plant were sampled on a grid with 121 points within a plot of 25,600 m 2 in area and slope of 0.025 mm -1 slope. Medium and low coefficients of variation were obtained for most of the studied soil attributes as expected, due to the homogenizing effect of the no-till system on the soil physical environment. From the standpoint of linear regression and spatial pattern of variability, productivity of soybeans could be explained according to the hydrogen potential (pH). Results are discussed taken into account that the soybean crop in no-tillage is widely used in crop-livestock integration on the national scene.

β-conglycinin combined with fenofibrate or rosuvastatin have exerted distinct hypocholesterolemic effects in rats

Background: There is increasing interest in non-pharmacological control of cholesterol and triglyceride levels in the plasma and diet-drug association represent an important area of studies. The objective of this study was to observe the hypocholesterolemic effect of soybean β-conglycinin (7S protein) alone and combined with fenofibrate and rosuvastatin, two hypolipidemic drugs. Methods. The protein and drugs were administered orally once a day to rats and the effects were evaluated after 28 days. Wistar rats were divided into six groups (n = 9): hypercholesterolemic diet (HC), HC+7S protein (300 mg.kg-1 day-1) (HC-7S), HC+fenofibrate (30 mg.kg-1 day-1)(HC-FF), HC+rosuvastatin (10 mg.kg-1 day-1)(HC-RO), HC+7S+fenofibrate (HC-7S-FF) and HC+7S+rosuvastatin (HC-7S-RO). Results: Animals in HC-7S, HC-FF and HC-RO exhibited reductions of 22.9, 35.8 and 18.8% in total plasma cholesterol, respectively. In HC-7S-FF, animals did not show significant alteration of the level in HC+FF while the group HC-7S-RO showed a negative effect in comparison with groups taking only protein (HC-7S) or drug (HC-RO). The administration of the protein, fenofibrate and rosuvastatin alone caused increases in the plasma HDL-C of the animals, while the protein-drug combinations led to an increase compared to HC-FF and HC-RO. The plasma concentration of triacylgycerides was significantly reduced in the groups without association, while HC-7S-FF showed no alteration and HC-7S-RO a little reduction. Conclusion: The results of our study indicate that conglycinin has effects comparable to fenofibrate and rosuvastatin on the control of plasma cholesterol, HDL-C and triacylglycerides, when given to hypercholesterolemic rats, and suggests that the association of this protein with rosuvastatin alters the action of drug in the homeostasis of cholesterol. © 2012 Ferreira et al; licensee BioMed Central Ltd.

Doses e épocas de aplicação de nitrogênio em cobertura na qualidade fisiológica de sementes de milho doce

The amount and timing of nitrogen application can favor seed quality, such as increasing protein content, which is an important constituent for embryo development. The objective of this study was to evaluate the physiological quality of sweet corn seeds collected from plants cultivated with different dosages and timings of nitrogen top-dressing applications. Seeds of the BR 400 variety (Super Sweet) were used obtained from plants submitted to dosages of 0, 40, 80 and 120kg ha -1 of N in two top-dressing applications (vegetative and reproductive stages). The weight of 100 grains, germination, first count of germination test, dry weight of normal seedlings from the germination test, seedling growth, cold test, accelerated aging, tetrazolium vigor and electric conductivity and emergency speed rate were determined. Data was submitted to an analysis of variance using the F-test at the 5% level and second degree regression analysis. The dosage and time of application of nitrogen top-dressing did not affect seed weight or the germination of sweet corn seeds. An increase of the N top-dressing dosage, applied in the vegetative stage reduced the length of the aerial part, the root and the whole seedling.

Nutritional evaluation of soy yoghurt in comparison to soymilk and commercial milk yoghurt. Effect of fermentation on soy protein

Soymilk was fermented using Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus. The soy yoghurt produced was evaluated in comparison to soymilk and commercial milk yoghurt by biological evaluation, rat growth, nitrogen balance assays and microbiological methods. Trypsin inhibitor activity and chemical composition were also determined for all samples. For the soy yoghurt, the growth and nitrogen balance values were not different from the control diet, but the nitrogen balance values were higher than for the soymilk, without significant difference in terms of growth assays. Compared to the commercial yoghurt, Net Protein Ratio and Nitrogen Utilization values were lower, but the Protein Efficiency Ratio, Biological Value and Net Protein Utilization values were equivalent, and for digestibility assays the best results were obtained with the soy yoghurt. The results indicated that soy yoghurt represents a good protein alternative to milk yoghurt and casein. The protein quality of soymilk evidently increased during the fermentation process using Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus, including a reduction in trypsin inhibitor levels of about 30%.

Dispersion and evaporation of droplets amended with adjuvants on soybeans

Quantification of the effects of adjuvants on droplet behaviour on plant surfaces is needed to improve pesticide spray application efficiency for soybeans. Dispersion and evaporation of single 300-μm diameter droplets amended with each of four spray adjuvants at five concentrations were investigated for four soybean plant surfaces (abaxial and adaxial leaflet surfaces, petiole, basal stem). The four adjuvants were a crop oil concentrate (COC), a modified seed oil (MSO), a non-ionic surfactant (NIS) and an oil surfactant blend (OSB). A single-droplet generator was used to produce and deposit 300-μm diameter droplets on target surfaces under controlled environmental conditions. Adjuvants significantly increased the dispersion (or wetted area) of droplets on plant surfaces. Droplet-wetted areas increased with increased adjuvant concentrations but not in direct proportion. The average increases of wetted areas across the four soybean plant surfaces were 443, 462, 416, or 343% when the spray mixture was amended with COC, MSO, NIS or OSB at the manufacturer-recommended concentrations, respectively. Among the four surfaces, the largest wetted area was on the abaxial surface, followed by the adaxial surface, the petiole and then the basal stem. Droplet evaporation times were inversely proportional to the wetted areas. The evaporation time of 300-μm diameter droplets ranged from 36 to 142. s on the four surfaces when the spray mixture was amended with an adjuvant, whereas the water-only droplets ranged from 161 to 190. s. The results demonstrated that use of adjuvants offers great potential to improve the homogeneity of sprayed pesticides, to increase spray coverage and to reduce pesticide application rates on soybean plants. These effects could benefit farmers economically and reduce environmental contamination by pesticides. © 2012.

Manejo de plantas daninhas e sua relação com a produtividade e potencial fisiológico de sementes de feijoeiro

Common bean is an important crop in Brazil primarily because of its nutritional characteristics. Some agronomic practices, such as weed management, are fundamental to cultivation, as a means of obtaining a high crop yield. However, some studies have shown that weed management may alter the function of the cultivar cycle. Thus, this study aimed at determining the optimal phenological stage in early-maturing common bean cultivars to perform the weed control without providing reductions in yield and seed quality. The experimental design was randomized blocks with 20 treatments and four replications, in a 2×2×5 (cultivars × types of weed control × periods of weed control) factorial scheme. The periods of weed control for both cultivars (Carioca Precoce and IPR-Colibri) consisted of full cycle weeded (control), weed control at the V4-3 stage (first three nodes on the main stem with trifoliate leaves), at the R5 stage (beginning of bloom) and at the R8 stage (appearance of pods) and full cycle unweeded (no weed control). The types of weed control used were chemical (fluazifop-p-butyl + fomesafen) and mechanical (hoe). The Carioca Precoce cultivar demonstrated higher agronomic performance and yield than the IPR-Colibri cultivar, although the IPR-Colibri seeds had a higher vigor. The type of weed control (chemical or mechanical) did not affect the agronomic characteristics, yield and seed physiological potential of the cultivars. The ideal period for weed control in early-maturing common bean cultivars to obtain a higher yield and seed physiological potential was observed at the V4-3 phenological stage.

Spatial Distribution of Euschistus heros (F.) (Hemiptera: Pentatomidae) in Soybean

Soybean bugs are major crop pests that cause significant reduction in harvest yield and influence grain quality. The aim of this study was to verify the spatial distribution of Euschistus heros (F.) (Hemiptera: Pentatomidae) in conventional and transgenic soybean cultivars. The experiment was conducted during the 2010-2011 crop season in UNESP/FCAV, Jaboticabal, SP, Brazil, in two fields of 10,000-m2 area that were subdivided into 100 plots (10 m × 10 m). The cultivars sown were M 7908 RR and its isoline M-SOY 8001. The number of the first to fifth instars and the number of adults were determined. To evaluate insect dispersion in the area, the following indices were used: variance/mean ratio, Morisita index, Green coefficient, and the k exponent of the negative binomial distribution. To study probabilistic models to describe the spatial distribution of the insects, the adjustments of the Poisson and negative binomial distributions were tested. The first to third instars showed aggregated spatial distribution, whereas the fourth and fifth instars, and adults, isolated or grouped, showed variation in the arrangement, ranging from moderately aggregated to randomly dispersed. During the adjustment of probability distributions, the negative binomial distribution model showed adjustment for the first to third instars, fourth and fifth instars, adults, and fourth and fifth instars plus adults. © 2013 Sociedade Entomológica do Brasil.

Densidade e época de semeadura de duas espécies de Brachiaria sobre a cultura da soja

The aim of this study was to evaluate the growth and yield of soybean cultivar M-8766 in consortium with Brachiaria brizantha. BRS Piata and Brachiaria ruziziensis at different densities and sowing dates. The experimental design was randomized blocks with treatments arranged in a factorial 2 × 2 × 3 with four replications. Used as factors grass species (Brachiaria brizantha Piata and Brachiaria ruziziensis BRS) intercropped with soybean M-8766, sowing dates (12 and 24 days after soybean emergence) and three seeding rates (0, 5, 10 kg ha-1 of seed). At 71 days after soybean emergence were evaluated plant height, stem diameter, dry mass of leaves, stems and shoots, and 4 months after sowing determined the weight of 100 grains and soybean yield. The results showed that when seeded at a density of 10 kg ha-1 at 12 and 24 DAE soy, Brachiaria brizantha. BRS Piata caused reduction in yield in the order of 6.71% and 3.03% respectively, while the Brachiaria ruziziensis was one that caused a greater reduction in productivity in the order of 13.42 and 16.23%, respectively, of these values expression when considering the price of soybean sack. B. ruziziensis expressed less competitive with soybean. However, the large biomass production of this grass provides deployment system till the next harvest.

Soil organic matter and physical attributes affected by crop rotation under no-till

Growing cover crops in systems under no tillage affects different pools of soil organic matter, and eventually soil physical attributes are modified. The objective of this study was to evaluate changes in soil organic matter and their relationship with soil physical attributes as affected by plant species grown in rotation with soybean [Glycine max (L.) Merr.] under no-till for 3 yr. Crop rotations included grain sorghum [Sorghum bicolor (L.) Moench], ruzigrass [Urochloa ruziziensis (R. Germ, and CM. Evard) Crins] and sorghum mixed with ruzigrass, all grown in fall/winter, followed by pearl millet [Pennisetum americanum (L.) Leeke], sunn hemp (Crotalaria juncea L.) and sorghum-sudangrass [S. bicolor × S. sudanense (Piper) Stapf] grown during the spring, plus a fallow check plot. Soybean was grown as the summer crop. Millet and sorghum-sudangrass cropped in spring showed higher root and shoot production as spring cropping. In fall/winter, sorghum mixed with ruzigrass yielded higher phytomass compared with sole cropping. Soil physical attributes and organic matter fractioning were positively affected by cropping millet and sorghum-sudangrass whereas intermediate effects were observed after sunn hemp. Maintaining fallow in spring had negative effects on soil organic matter and physical properties. Ruzigrass and sorghum mixed with ruzigrass cropped in fall/winter resulted in better soil quality. Spring cover crops were more efficient in changing soil bulk density, porosity, and aggregates down to 0 to 10 cm; on the other hand, fall/winter cropping showed significant effects on bulk density in the uppermost soil layer. Total C levels in soil were increased after a 3-yr rotation period due to poor initial physical conditions. Fractions of particulate organic C, microbial C, and C in macroaggregates were the most affected by crop rotations, and showed high relation with improved soil physical attributes (porosity, density, and aggregates larger than 2 mm). © Soil Science Society of America, All rights reserved.

Vigor de sementes, população de plantas e desempenho agrônomico de soja

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Caracterização sistêmica de alterações em redes fisiológicas de plantas C3 e C4 submetidas à deficiência hídrica

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Sistemas de manejo e qualidade física em latossolo vermelho

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)