Scientia Agricola, Volume: 73, Issue: 4, Published: 2016
  • Bacterial strains from floodplain soils perform different plant-growth promoting processes and enhance cowpea growth AGRICULTURAL MICROBIOLOGY

    Costa, Elaine Martins da; Carvalho, Fernanda de; Nóbrega, Rafaela Simão Abrahão; Silva, Jacqueline Savana; Moreira, Fatima Maria de Souza

    Abstract in English:

    ABSTRACT Certain nodulating nitrogen-fixing bacteria in legumes and other nodule endophytes perform different plant-growth promoting processes. The objective of this study was to evaluate 26 bacterial strains isolated from cowpea nodules grown in floodplain soils in the Brazilian savannas, regarding performance of plant-growth promoting processes and ability to enhance cowpea growth. We also identified these strains by 16S rRNA sequencing. The following processes were evaluated: free-living biological nitrogen fixation (BNF), solubilization of calcium, aluminum and iron phosphates and production of indole-3-acetic acid (IAA). The abilities to nodulate and promote cowpea growth were evaluated in Leonard jars. Partial sequencing of the 16S rRNA gene identified 60 % of the strains as belonging to genus Paenibacillus. The following four genera were also identified: Bacillus, Bradyrhizobium, Enterobacter and Pseudomonas. None of the strains fixed N2 free-living. Among the strains, 80 % solubilized Ca phosphate and one solubilized Al phosphate and none solubilized Fe phosphate. The highest IAA concentrations (52.37, 51.52 and 51.00 μg mL−1) were obtained in the 79 medium with tryptophan by Enterobacter strains UFPI B5-7A, UFPI B5-4 and UFPI B5-6, respectively. Only eight strains nodulated cowpea, however, all increased production of total dry matter. The fact that the strains evaluated perform different biological processes to promote plant growth indicates that these strains have potential use in agricultural crops to increase production and environmental sustainability.
  • Agriculture and food security challenge of climate change: a dynamic analysis for policy selection AGROMETEOROLOGY

    Ahmed, Ferdous; Al-Amin, Abul Quasem; Mohamad, Zeeda Fatimah; Chenayah, Santha

    Abstract in English:

    ABSTRACT This study presents an empirical examination of climate change related to vulnerability impacts on food security and remedial adaptation options as a suitable strategy by prioritizing needs over a 50-year period. An Empirical Dynamic Commutable General Equilibrium Model for Climate and the Economy (EDCGECE) is applied using future strategies for Malaysia against a baseline scenario of existing conditions, following the top-down options. The model takes into account various climatic variables, including climatic damage, carbon cycle, temperature and rainfall fluctuation, carbon emissions, vulnerability and carbon concentrations, which were adapted from national observational predictions of climatic changes caused by global warming from 2015 to 2065. The results prioritize climate change mitigation for the future. Specifically, this study estimates Malaysia’s food sustainability prospects without adaptation actions and with 5 % to 20 % adaptation actions overtime in different adaptation scenarios, as contrasted with the baseline. The results indicate that food sustainability cost in the baseline in 2015 is 859.3 million US Dollar (USD), which is about a 30-35 % shortage compared with the national targets, and that the shortage will rise over time to USD 987.3 million in 2065. However, the cost of applying different levels of adaptation for food sustainability over time is rising considerably. However, the residual damage also decreases with all adaptation actions in the different scenarios. Thus, adaptation shows a positive sign for Malaysia’s agricultural sectors. As growth values are positive and show rising trends, therefore the projected adaptation policy can be effective for food sustainability for sustainable future strategies in Malaysia.
  • Effects of glutamine on performance and intestinal mucosa morphometry of broiler chickens vaccinated against coccidiosis ANIMAL SCIENCE AND PASTURES

    Luquetti, Brenda Carla; Alarcon, Miguel Frederico Fernandez; Lunedo, Raquel; Campos, Daniel Mendes Borges; Furlan, Renato Luís; Macari, Marcos

    Abstract in English:

    ABSTRACT This study aimed to assess the effects of glutamine as feed additive on performance and intestinal mucosa morphometry of broiler chickens vaccinated against coccidiosis. A total of 400 day-old male chicks were randomly assigned to four treatments (NVNG – no vaccination, no glutamine supplementation; NVG – no vaccination, glutamine supplementation (10 g kg−1); VNG – vaccination, no glutamine supplementation; VG – vaccination, glutamine supplementation) replicated four times with 25 birds per replicate. A commercial sprayed-on vaccine against coccidiosis containing Eimeria acervulina, E. maxima, E. mivati, and E. tenella was administered at the hatchery. Broiler performance was evaluated from 1-28 days, and morphometric parameters were analyzed at 14, 21, and 28 days of age. Body weight gain and feed intake were negatively affected by vaccination, but not by glutamine. Vaccination increased crypt depth in the duodenum and jejunum at 21 and 28 days. In conclusion, this study showed that glutamine was not able to increase weight gain of broiler chickens, irrespective of whether the animals were vaccinated or not against coccidiosis. Glutamine supplementation was able to improve feed conversion in vaccinated birds suggesting trophic effect on intestinal epithelium improving.
  • Meta-analysis of individual and combined effects of mycotoxins on growing pigs ANIMAL SCIENCE AND PASTURES

    Andretta, Ines; Kipper, Marcos; Hauschild, Luciano; Lehnen, Cheila Roberta; Remus, Aline; Melchior, Raquel

    Abstract in English:

    ABSTRACT Little is known about the toxicity of concomitantly occurring mycotoxins in pig diets. This study was conducted to evaluate, through meta-analysis, the individual and the combined effects of mycotoxins on pig performance. The meta-analysis followed three sequential analyses (graphical, correlation, and variance-covariance) based on a database composed of 85 published papers, 1,012 treatments and 13,196 animals. Contamination of diets with individual mycotoxins reduced (p < 0.05) feed intake by 14 % and weight gain by 17 %, while combined mycotoxins reduced the same responses by 42 % and 45 %, respectively, in comparison with the non-challenged group. The correlation (p < 0.05) between reduction in weight gain (ΔG) and reduction in feed intake (ΔFI) was 0.67 in individual challenges and 0.93 in combined challenges. The estimated ΔG was –6 % in individual challenges and –7 % in combined challenges when ΔFI was zero, suggesting an increase in the maintenance requirements of challenged animals. Most of ΔG (58 % in individual challenges and 84 % in combined challenges) was attributed to the changes in feed efficiency. The association of mycotoxins enhances individual toxic effects and the ΔFI is important in explaining the deleterious effects on the growth of challenged pigs.
  • Temporal profiles of vegetation indices for characterizing grazing intensity on natural grasslands in Pampa biome ANIMAL SCIENCE AND PASTURES

    Junges, Amanda Heemann; Bremm, Carolina; Fontana, Denise Cybis; Oliveira, Carlos Alberto Oliveira de; Schaparini, Laura Pigatto; Carvalho, Paulo César de Faccio

    Abstract in English:

    ABSTRACT The Pampa biome is an important ecosystem in Brazil that is highly relevant to livestock production. The objective of this study was to analyze the potential use of vegetation indices to discriminate grazing intensities on natural grasslands in the Pampa biome. Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) images from Jan to Dec, 2000 to 2013 series, were analyzed for natural grassland experimental units managed under high (forage allowance of 5 ± 2 % live weight – LW), moderate (13 ± 5 % LW) and low grazing intensity (19 ± 7 % LW). Regardless of intensity, the temporal profiles showed lower NDVI and EVI during winter, increased values in spring because of summer species regrowth, slightly decreased values in summer, especially in years when there is a water deficit, and increased values in the fall associated with the beginning of winter forage development. The average temporal profiles of moderate grazing intensity exhibited greater vegetation index values compared with low and high grazing intensities. The temporal profiles of less vegetation index were associated with lower green biomass accumulation caused by the negative impact of stocking rates on the leaf area index under high grazing intensity and a floristic composition with a predominance of tussocks under low grazing intensity. Vegetation indices can be used for distinguishing moderate grazing intensity from low and high intensities. The average EVI values can discriminate moderate grazing intensity during any season, and the NDVI values can discriminate moderate grazing intensity during spring and winter.
  • Yield and nitrogen fixation potential from white lupine grown in rainfed Mediterranean environments CROP SCIENCE

    Sulas, Leonardo; Canu, Simone; Ledda, Luigi; Carroni, Antonio Melchiorre; Salis, Mauro

    Abstract in English:

    ABSTRACT There is renewed interest in white lupine (Lupinus albus L.), which is appreciated for its high protein content, full range of essential amino acids and as N source to rainfed cropping systems. Unfortunately, information on its N2 fixation ability is limited. This study aimed to: (i) quantify the N2 fixation ability of white lupine crop at the plot field scale in three different environments of Sardinia (Italy) under Mediterranean climate; (ii) determine the allocation of the plant-fixed N into different organs; and (iii) establish the relationship between fixed N and DM within plant organs. In a 2-year experiment, N2 fixation was estimated using the 15N isotopic dilution method. The productive performances and ability of white lupine to fix N2 widely differed in the three environments; peak values exceeded 300 kg ha−1 of fixed N. There were significant differences in the quantity of fixed N found in each plant organ at physiological maturity with 5, 20, 19 and 57 % of fixed N partitioned to roots, shoots, pod valves and grain, respectively. After grain harvesting, the net N balance ranged from negative values to 160 kg N ha−1. The relationship between fixed N and DM yield indicated 60, 34, 8 and 6 kg of fixed N per t of grain, pod valves, shoots and root, respectively, showing that fixed N preferentially accumulated in seeds at physiological maturity. Due to its high potential for N2 fixation and N benefit, white lupine represents a valuable crop option under rainfed Mediterranean conditions.
  • Sensory and physicochemical characteristics of low sodium salami FOOD SCIENCE AND TECHNOLOGY

    Almeida, Marcio Aurelio de; Villanueva, Nilda Doris Montes; Pinto, Jair Sebastião da Silva; Saldaña, Erick; Contreras-Castillo, Carmen J.

    Abstract in English:

    ABSTRACT The aim of the present study was to develop low sodium salami prepared with pork, low-fat beef and a small quantity of pork back fat (150 g kg−1). Sodium chloride (NaCl) was replaced by potassium chloride (KCl) and calcium chloride (CaCl2), and salamis were tasted to obtain low-salt salami with sensory characteristics similar to those found in commercial ones. Salamis were prepared following seven different treatments. Treatments included five different combinations of KCl and CaCl2 which varied from 5 g kg−1 to 10 g kg−1 and two controls containing high (25 g kg−1) and low (10 g kg−1) concentrations of NaCl. The right level of saltiness of each treatment was evaluated on “just-about-right” (JAR) scales and analyzed by Penalty Analysis. The results showed differences in pH and Aw (water activity) due to NaCl reduction. Salt replacement mixtures of KCl/CaCl2 in salamis did not affect this process technologically (slicing, appearance and texture), and the decrease in Na content was approximately 55 %. Although no significant differences were observed in appearance, treatments differed (p ≤ 0.05) in flavor, texture, and overall liking. As regards salt content of salami, consumers considered treatments with low NaCl content and replacers KCl and CaCl2 (% Na) as having an acceptable level of saltiness. However, this replacement produced a strange taste. Thus, the production of low sodium salamis using salt replacers (KCl and CaCl2) or salamis without replacers with a value higher than 1 % of NaCl can be used effectively without compromising major sensorial attributes.
  • Interspecific hybrids between Paspalum plicatulum and P. oteroi: a key tool for forage breeding GENETICS AND PLANT BREEDING

    Novo, Patricia Elda; Valls, José Francisco Montenegro; Galdeano, Florencia; Honfi, Ana Isabel; Espinoza, Francisco; Quarin, Camilo Luis

    Abstract in English:

    ABSTRACT Grama-tio-pedro (Paspalum oteroi Swallen) is a rare stoloniferous grass of the Plicatula group of Paspalum, well adapted to continuous grazing in areas subject to seasonal flooding in the Pantanal region, in central western Brazil. The species is a facultative apomictic (asexual reproduction by seed) tetraploid, sporadically cultivated on Pantanal farms, propagated either by cuttings or seed. Due to its potential for extensive cultivation and forage quality, Grama-tio-pedro appears as a candidate for genetic improvement within the Plicatula group through plant breeding. We used a colchicine-induced sexual autotetraploid genotype of P. plicatulum Michx. to obtain interspecific hybrids using the apomictic species, P. oteroi, as pollen donor. The very similar meiotic chromosome behavior observed in both parents, with main quadrivalent and bivalent associations, suggested that P. oteroi is a natural autotetraploid. The hybrids showed less irregular meiotic behavior with fewer quadrivalents and more bivalents than either parent. Fertility among interspecific hybrids varied from complete sterility in some of them to seed productions in others that were approximately twice as much as for either parent. The great variability of seed set performance may well be a drastic genetic consequence of joining two homologous chromosome sets of P. plicatulum together with two homologous sets of P. oteroi that, in turn, have some homeology between them. Most hybrids reproduce by sexual means, thus, they could be used as female parents in backcrosses and in crosses with other species of the Plicatula group for interspecific gene transferring in breeding programs.
  • Geomorphometric tool associated with soil types and properties spatial variability at watersheds under tropical conditions SOILS AND PLANT NUTRITION

    Silva, Sérgio Henrique Godinho; Menezes, Michele Duarte de; Mello, Carlos Rogério de; Góes, Helen Thaís Pereira de; Owens, Phillip Ray; Curi, Nilton

    Abstract in English:

    ABSTRACT The application of quantitative methods to digital soil and geomorphological mapping is becoming an increasing trend. One of these methods, Geomorphons, was developed to identify the ten most common landforms based on digital elevation models. This study aimed to make a quantitative assessment of the relationships between Geomorphons units, determined at three spatial resolutions and nine radii, and soil types and properties of two watersheds with different soil-landscape relationships in Brazil to help soil surveying and mapping under tropical conditions. The study was conducted at Lavrinha Creek (LCW) and Marcela Creek (MCW) watersheds, located in the state of Minas Gerais, Brazil. Spatial resolutions of 10, 20 and 30 m were the basis for generating Geomorphons at 9 radii of calculation for the watersheds. They were overlapped to detailed soil maps of the watersheds and a chi-square test was carried out to assess their relationship with soil types. Observation points were compared with the most highly correlated Geomorphons to also assess relationships with soil properties. Geomorphons with resolution of 30-m and radii of 20 and 50 cells, respectively for LCW and MCW, were more highly correlated with the variability of soil types, in accordance with the terrain features of these watersheds. The majority of observation points for each soil type was located in the same Geomorphon unit that was dominant when analyzing soil maps. There was less variability in soil properties between Geomorphon units, which was probably due to the highly weathered-leached stage of soils. Geomorphons can help to improve soil maps in tropical conditions when assessing soil variability due to its high correlation with tropical soil types variability.
  • Humic substances and its distribution in coffee crop under cover crops and weed control methods SOILS AND PLANT NUTRITION

    Martins, Bruno Henrique; Araujo-Junior, Cezar Francisco; Miyazawa, Mario; Vieira, Karen Mayara

    Abstract in English:

    ABSTRACT Humic substances (HS) comprise the passive element in soil organic matter (SOM), and represent one of the soil carbon pools which may be altered by different cover crops and weed control methods. This study aimed to assess HS distribution and characteristics in an experimental coffee crop area subjected to cover crops and cultural, mechanical, and chemical weed control. The study was carried out at Londrina, in the state of Paraná, southern Brazil (23°21’30” S; 51°10’17” W). In 2008, seven weed control/cover crops were established in a randomized block design between two coffee rows as the main-plot factor per plot and soil sampling depths (0-10 cm, 10-20 cm, 20-30 cm and 30-40 cm) as a split-plot. HS were extracted through alkaline and acid solutions and analyzed by chromic acid wet oxidation and UV-Vis spectroscopy. Chemical attributes presented variations in the topsoil between the field conditions analyzed. Cover crop cutting and coffee tree pruning residues left on the soil surface may have interfered in nutrient cycling and the humification process. Data showed that humic substances comprised about 50 % of SOM. Although different cover crops and weed control methods did not alter humic and fulvic acid carbon content, a possible incidence of condensed aromatic structures at depth increments in fulvic acids was observed, leading to an average decrease of 53 % in the E4/E6 ratio. Humin carbon content increased 25 % in the topsoil, particularly under crop weed-control methods, probably due to high incorporation of recalcitrant structures from coffee tree pruning residues and cover crops.
  • The recent similarity hypotheses to describe water infiltration into homogeneous soils SOILS AND PLANT NUTRITION

    Reichardt, Klaus; Timm, Luís Carlos; Dourado-Neto, Durval

    Abstract in English:

    ABSTRACT A similarity hypothesis recently presented to describe horizontal infiltration into homogeneous soils, developed for coarse-textured soils like sieved marine sand, implies that the soil water retention function θ(h) is the mirror image of an extended Boltzmann transform function θ(λ2). A second hypothesis applicable to vertical infiltration suggests that the soil water retention function θ(h) is also the mirror image of the soil water profile θ(z). Using previously published infiltration data, we investigated whether these two similarity solutions successfully describe infiltration into two “normal” soils. Although the theory using the first similarity assumption adequately describes horizontal cumulative infiltration and infiltration rate into both soils, it fails to estimate soil water distributions measured between soil profiles. The second similarity solution for vertical infiltration into either soil completely fails to coincide with measured soil water distributions, cumulative infiltration and infiltration rate.
  • Infection process of Phakopsora gossypii in cotton leaves NOTE

    Araujo, Leonardo; Guerra, Antonia Mirian Nogueira Moura; Berger, Paulo Geraldo; Rodrigues, Fabrício Ávila

    Abstract in English:

    ABSTRACT Tropical rust caused by the biotrophic fungus Phakopsora gossypii is an emerging disease in cotton that has caused significant yield losses of crop/cotton cultivated in Brazil. Considering the current importance of tropical rust and the need to obtain additional basic information about its causal agent to better control this disease, the present study aimed to determine the infection process of P. gossypii in cotton leaves using scanning electron microscopy (SEM). Thirty-day-old plants were inoculated with a suspension of P. gossypii uredospores, and leaf fragments were collected 42 h after inoculation (hai) as well as 20, 25 and 35 days after inoculation (dai) for SEM observations. By 42 hai, the uredospores of P. gossypii had germinated and produced a germ tube and an appressorium that may directly penetrate the leaf cuticle. At 20 dai, closed uredia containing uredospores were observed on the abaxial leaf surface. At 25 dai, the uredia started to open and became fully open by 35 dai and contained many uredospores. By 25 dai, fungal hyphae were growing abundantly in the mesophyll next to the uredia that formed in the leaf fragments with total or partial removal of the epidermis. The results of the present study provide novel information regarding the infection process of P. gossypii in cotton leaves, which might be useful for the development of new and more effective strategies for tropical rust control.
  • Software for micromorphometric characterization of soil pores obtained from 2-D image analysis NOTE

    Cooper, Miguel; Boschi, Raquel Stucchi; Silva, Vitor Boschi da; Silva, Laura Fernanda Simões da

    Abstract in English:

    ABSTRACT Studies of soil porosity through image analysis are important to an understanding of how the soil functions. However, the lack of a simplified methodology for the quantification of the shape, number, and size of soil pores has limited the use of information extracted from images. The present work proposes a software program for the quantification and characterization of soil porosity from data derived from 2-D images. The user-friendly software was developed in C++ and allows for the classification of pores in terms of size, shape, and combinations of size and shape. Using raw data generated by image analysis systems, the software calculates the following parameters for the characterization of soil porosity: total area of pore (Tap), number of pores, pore shape, pore shape and pore area, and pore shape and equivalent pore diameter (EqDiam). In this paper, the input file with the raw soil porosity data was generated using the Noesis Visilog 5.4 image analysis system; however other image analysis programs can be used, in which case, the input file requires a standard format to permit processing by this software. The software also shows the descriptive statistics (mean, standard deviation, variance, and the coefficient of variation) of the parameters considering the total number of images evaluated. The results show that the software is a complementary tool to any analysis of soil porosity, allowing for a precise and quick analysis.
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