Effect of Salinity Stress on Various Growth and Physiological Attributes of Two Contrasting Maize Genotypes

Abstract The response of two local maize (Zea mays L.) genotypes designated as Sahwal-2002 (salt-tolerant) and Sadaf (salt-sensitive) to salt stress was investigated under controlled growth conditions. The role of phenylalanine and seed priming under salt stress in maize with different morphological parameters were studied. The genotype Sadaf, being salt-tolerant, experienced more oxidative damage than the Sahiwall-2002 genotype under salt stress. The salinity affected both growth and physiological attributes of the maize species whereas the phenylalanine successfully increased the salinity tolerance in maize species at the seedling stage.

Chemical Recovery of Degraded Soil and Consequence in the Cost of Corn Production

Abstract Improper management degrades the soil, decreases corn productivity and is reflected in the cost of production. The objective of this research was to evaluate the soil recovery in non-conservationist treatments after the change of management and cultivation to the conservation condition direct sowing, and compare these systems to consolidated direct seeding; This evaluation was based on the soil responsiveness to crop production and water erosion control, and based on the financial cost of soil recovery and corn production when soil management was converted from non-conservationist (tillage rotation - RT, minimum tillage - MT, conventional tillage - CT and bare soil - BS) to no-tillage (NT) condition, in a Humic Cambisol. The transition from managements to no-tillage occurred in 2015 year, after 27 years of conducting the preexisting managements. The chemical recovery was carried out with the application of limestone, phosphorus, and potassium. At the end of the research the yield of the corn crop, the cost of recovering the soil fertility and the cost of crop production were evaluated. Previous soil management influenced the cost of soil chemical recovery. The cost of production showed a financial loss for the previous treatments CT and BS, on the average of the three corn crops.

Outstanding impact of soil tillage on the abundance of soil hydrolases revealed by a metagenomic approach

ABSTRACT The soil represents the main source of novel biocatalysts and biomolecules of industrial relevance. We searched for hydrolases in silico in four shotgun metagenomes (4,079,223 sequences) obtained in a 13-year field trial carried out in southern Brazil, under the no-tillage (NT), or conventional tillage (CT) managements, with crop succession (CS, soybean/wheat), or crop rotation (CR, soybean/maize/wheat/lupine/oat). We identified 42,631 hydrolases belonging to five classes by comparing with the KEGG database, and 44,928 sequences by comparing with the NCBI-NR database. The abundance followed the order: lipases > laccases > cellulases > proteases > amylases > pectinases. Statistically significant differences were attributed to the tillage system, with the NT showing about five times more hydrolases than the CT system. The outstanding differences can be attributed to the management of crop residues, left on the soil surface in the NT, and mechanically broken and incorporated into the soil in the CT. Differences between the CS and the CR were slighter, 10% higher for the CS, but not statistically different. Most of the sequences belonged to fungi (Verticillium, and Colletotrichum for lipases and laccases, and Aspergillus for proteases), and to the archaea Sulfolobus acidocaldarius for amylases. Our results indicate that agricultural soils under conservative managements may represent a hotspot for bioprospection of hydrolases.

Potential of natural repellents methylanthranilate and anthraquinone applied on maize seeds and seedlings against house sparrow (Passer domesticus) in captivity / Potencial de repelentes naturais, metilantranilato e antraquinona aplicados em sementes de milho e mudas contra o pardal (Passer domesticus) em cativeiro

Abstract Various bird pests caused severe economic losses to valuable crops and fruit orchards all over the world. Among the birds, house sparrow is also considered to cause heavy plunder, not only to seeds of crops but also seedlings especially in organic farming. In present study two bird repellents, methylanthranilate and anthraquinone tested against house sparrows on maize seeds and seedlings in aviary conditions. Trial group in aviary-I, the treated maize seeds and seedlings with different doses of both bird repellents, control group in aviary-II, untreated seeds and seedlings were provided for three hours in the early morning. In each aviary, two closed circuit cameras were also installed to monitor the behavioral responses against different concentrations of both chemical repellents. Statistical analysis showed that there existed highly significant (P<0.01) variations among the trial and control groups for seeds and seedlings. By comparing both repellents, significant (P<0.05) differences were detected and anthraquinone showed better efficacy when compared to methylanthranilate, but in maize seedlings both repellents equal repellent properties. Non-significant (P>0.05) differences were observed in different grading of both natural chemical repellents for maize seeds while significant (P<0.05) variations were noticed for maize seedlings when provided to sparrows. By videotaped behavior sparrows presented manifest head juddering and feather upsetting activities by consumption of treated seeds and seedlings with higher concentrations of both natural bird repellents.

Resumo Várias pragas de aves causaram graves perdas econômicas para cultivos valiosos e pomares de frutas em todo o mundo. Entre os pássaros, o pardal da casa também é considerado um grande saqueo, não só para as sementes das culturas, mas também para as mudas, especialmente na agricultura orgânica. No presente estudo, dois repelentes de aves, metilantranilato e antraquinona testados contra pardais de casa em sementes de milho e mudas em condições de aviário. O grupo de ensaio em aviary-I, as sementes de milho tratadas e as mudas com diferentes doses de repelentes de aves, grupo de controle em aviary-II, sementes não tratadas e mudas foram fornecidas por três horas no início da manhã. Em cada aviário, duas câmeras de circuito fechado também foram instaladas para monitorar as respostas comportamentais contra diferentes concentrações de ambos os repelentes químicos. A análise estatística mostrou que existiam variações altamente significativas (P<0,01) entre os grupos de teste e controle para sementes e mudas. Ao comparar os dois repelentes, detectaram-se diferenças significativas (P<0,05) e a antraquinona apresentou maior eficácia quando comparada ao metilantranilato, mas em mudas de milho, ambos os repelentes são iguais às propriedades repelentes. As diferenças não significantes (P>0,05) foram observadas em diferentes classificações de repelentes químicos naturais para sementes de milho, enquanto as variações significativas (P<0,05) foram observadas para as mudas de milho quando fornecidas aos pardais. Por um comportamento gravado em video, os pardais apresentaram manifestações de cabeça e vibrações de penas por consumo de sementes tratadas e mudas com maiores concentrações de repelentes de aves naturais.

Palisadegrass effects on N fertilizer dynamic in intercropping systems with corn

ABSTRACT Corn grain yield, nitrogen (N) fertilizer efficiency and distribution to corn alone and three forms of corn and palisadegrass (Urochloa spp.) intercropping implantation was investigated. A field experiment with 15N labeling fertilizer was performed in randomized block design. No form of palisadegrass intercropping implantation affected corn grain yield, total N accumulation and N use efficiency (NUE), which were 8.7 t ha-1, 205 kg ha-1 and 37% respectively. The palisadegrass produced on average 1.9 t of dry mass, absorbing a maximum of 6 kg ha-1 or 5.5% of N fertilizer during corn growing. Furthermore, the palisadegrass did not affect N fertilizer distribution in soil-plant system, in which 28.2% was recovered in the soil and 40.4% in the plants (corn + palisadegrass). The results show that for the three intercropping implantation methods the palisadegrass did not compete with corn for N fertilizer.

Maize dry matter production and macronutrient extraction model as a new approach for fertilizer rate estimation

ABSTRACT Decision support for nutrient application remains an enigma if based on soil nutrient analysis. If the crop could be used as an auxiliary indicator, the plant nutrient status during different growth stages could complement the soil test, improving the fertilizer recommendation. Nutrient absorption and partitioning in the plant are here studied and described with mathematical models. The objective of this study considers the temporal variation of the nutrient uptake rate, which should define crop needs as compared to the critical content in soil solution. A uniform maize crop was grown to observe dry matter accumulation and nutrient content in the plant. The dry matter accumulation followed a sigmoidal model and the macronutrient content a power model. The maximum nutrient absorption occurred at the R4 growth stage, for which the sap concentration was successfully calculated. It is hoped that this new approach of evaluating nutrient sap concentration will help to develop more rational ways to estimate crop fertilizer needs. This new approach has great potential for on-the-go crop sensor-based nutrient application methods and its sensitivity to soil tillage and management systems need to be examined in following studies. If mathematical model reflects management impact adequately, resources for experiments can be saved.

Simulation of maize growth under different sowing times and deficit irrigation conditions / Imulation of maize growth under different sowing times and deficit irrigation conditions

Simulation models of crops are referred as an efficient complement for the experimental study. Also crop simulation models can be useful for making appropriate decisions on agricultural systems. So this study aimed to simulate the growth of maize under different sowing times and deficit irrigation conditions, using the Decision Support System for Agrotechnology Transfer (DSSAT) model in 2014 year. This study was conducted in the research field of Islamic Azad University of Karaj in 2013 year. The experiment was designed in a split-block with four replications. Treatments included four sowing times of April 30 (S1), May 20 (S2), June 10 (S3), and June 27 (S4) in the main plots and three irrigation levels of 40% available water depletion (W1), 60% available water depletion (W2), and 80% available water depletion in the sub-plots. Root Mean Square Error (RMSE) of grain yield for all four sowing times on three levels of irrigation in Karaj region varied from 581.43 to 1,990.81 kg per hectare. It was also calculated the model efficiency coefficient (d) ranged 0.87-0.98 for the trait. The RMSE of the total dry matter was determined 861.88-2,173.66 kg per hectare; that was while R2 (1:1) of total dry weight varied 0.89-0.98. The results indicate that the model's ability to predict dry matter yield of maize is good enough.

Os modelos de simulação de culturas são referidos como um complemento eficaz para o estudo experimental. Os modelos de simulação de culturas também podem ser úteis para a tomada de decisões adequadas em sistemas agrícolas. Portanto, este estudo teve como objetivo simular o crescimento do milho sob diferentes épocas de semeadura e condições de déficit de irrigação, utilizando o Sistema de Apoio à Decisão para o modelo de Transferência de Agrotecnologia (DSSAT) no ano de 2014. Este estudo foi realizado no campo experimental da Islâmica Azad Universidade de Karaj no ano de 2013. O experimento foi desenvolvido com delineamento em faixas com 4 repetições. Os tratamentos incluíram quatro épocas de semeaduras de 30 de Abril (S1), 20 de maio (S2), 10 de junho (S3), e 27 de junho (S4) nas parcelas principais e três níveis de irrigação de esgotamento de 40% de água disponível (W1), 60% depleção de água disponível (W2), e 80% esgotamento da água disponível nos sub-parcelas. O erro da raiz do quadrado médio (RMSE) do rendimento de grãos para todas as quatro épocas de semeadura nos três níveis de irrigação na região Karaj variou de 581,43 a 1,990,81 kg por hectare. Também foi calculado o coeficiente de eficiência do modelo (d) que variou de 0,87 a 0,98 para a característica. O RMSE da matéria seca total foi determinada entre 861.88 e 2,173.66 kg por hectare; enquanto R2 (1:1) da massa total variou de 0,89 a 0,98. Os resultados indicam que a capacidade do modelo para prever a produção de matéria seca de milho é suficientemente boa.

Diversity and capacity to promote maize growth of bacteria isolated from the Amazon region / Diversidade e capacidade de promoção de crescimento de milho de bactérias isoladas da região Amazônica

Maize plants can establish beneficial associations with plant growth-promoting bacteria. However, few studies have been conducted on the characterization and inoculation of these bacteria in the Amazon region. This study aimed to characterize endophytic bacteria isolated from maize in the Amazon region and to assess their capacity to promote plant growth. Fifty-five bacterial isolates were obtained from maize grown in two types of ecosystems, i.e., a cerrado (savanna) and a forest area. The isolates were characterized by the presence of the nifH gene, their ability to synthesize indole-3-acetic acid (IAA) and solubilize calcium phosphate (CaHPO4), and 16S rRNA partial gene sequencing. Twenty-four bacteria contained the nifH gene, of which seven were isolated from maize plants cultivated in a cerrado area and seventeen from a forest area. Fourteen samples showed the capacity to synthesize IAA and only four solubilized calcium phosphate. The following genera were found among these isolates: Pseudomonas; Acinetobacter; Enterobacter; Pantoea; Burkholderia and Bacillus. In addition, eight isolates with plant growth-promoting capacity were selected for a glasshouse experiment involving the inoculation of two maize genotypes (a hybrid and a variety) grown in pots containing soil. Inoculation promoted the development of the maize plants but no significant interaction between maize cultivar and bacterial inoculation was found. A high diversity of endophytic bacteria is present in the Amazon region and these bacteria have potential to promote the development of maize plants.

Plantas de milho podem estabelecer associações benéficas com bactérias promotoras do crescimento vegetal. No entanto, poucos estudos de caracterização e inoculação com essas bactérias foram realizados na região Amazônica. O objetivo deste estudo foi caracterizar bactérias endofíticas isoladas de milho na região Amazônica e avaliar sua capacidade de promover o crescimento. Cinquenta e cinco isolados bacterianos foram obtidos de plantas de milho cultivadas em diferentes tipos de ecossistemas, cerrado (savana) e área de floresta. Estes foram caracterizados pela presença do gene nifH, capacidade de sintetizar ácido indol-3-acético (AIA), solubilizar fosfato de cálcio (CaHPO4) e sequenciamento parcial do gene 16S rRNA. Vinte e quatro bactérias apresentaram o gene nifH. Destas, sete são oriundas de plantas cultivadas em uma área de cerrado e 17 em área de floresta. Quatorze bactérias demonstraram a capacidade de solubilizar AIA e quatro de solubilizar fosfato de cálcio. Entre estas bactérias, foram encontrados os seguintes gêneros: Pseudomonas; Acinetobacter; Enterobacter; Pantoea; Burkholderia e Bacillus. Oito isolados com capacidade de promoção do crescimento vegetal foram selecionados para experimento em casa de vegetação com a inoculação em dois diferentes genótipos de milho (um híbrido e uma variedade) em vasos com solo. Quanto à promoção de crescimento vegetal, a inoculação promoveu o desenvolvimento de plantas de milho, mas não foi encontrada interação significativa entre a cultivar de milho e a inoculação bacteriana. Na região Amazônica há uma diversidade de bactérias endofíticas e estas possuem potencial para promover o desenvolvimento de plantas de milho.

Comportamento de milho híbrido para silagem em diferentes condições de sucessão de culturas no município de Umuarama - PR / Hybrid maize for silage in different crop succession conditions in the city of Umuarama - PR / Comportamiento de maíz híbrido para ensilaje en diferentes condiciones de sucesión de cultivos en el municipio Umuarama - PR

O objetivo do trabalho foi avaliar o comportamento do milho híbrido para silagem em diferentes condições de sucessão de culturas no município de Umuarama ­ PR. O experimento foi realizado em duas diferentes áreas da fazenda experimental da Universidade Paranaense ­ UNIPAR, no referido município. Na área 1 cultivou-se o milho em sucessão à cana-de-açúcar e na área 2, em sucessão à pastagem do gênero Brachiaria. O experimento foi conduzido no período de dezembro/2014 a abril/2015. Utilizou-se o milho híbrido 2B688 PW, cujos tratos culturais foram realizados conforme a necessidade da cultura. Após 78 dias da semeadura, foram amostradas, aleatoriamente, 19 parcelas de 8m² em cada área, onde se avaliou altura de plantas e de inserção de espiga, comprimento e diâmetro de espiga. Não foram verificadas diferenças significativas entre os tratamentos para todas as variáveis analisadas, evidenciando que a cultura do milho apresentou as mesmas respostas quando cultivada em sucessão à cana ou à pastagem de Brachiaria.

The purpose of this study was to evaluate the behavior of hybrid maize for silage in different crop succession conditions in the city of Umuarama ­ PR in two different areas. The experiment was performed at the experimental farm at Universidade Paranaense - UNIPAR in the aforementioned city. In area 1, maize was grown after sugarcane, while in area 2 it was grown after pasture with Brachiaria. The experiment was carried out from December/2014 to April/2015. Hybrid maize 2B688 PW was used, with cultural traits performed according to the crop needs. Seventy-eight days after sowing, 19 plots measuring 8 m2 each were randomly chosen and analyzed, assessing plant height and spike insertion, as well as length and spike diameter. There were no significant differences between treatments for all variables analyzed, therefore, it can be concluded that maize crop presented the same responses when grown in succession to sugarcane or to Brachiaria pasture.

El objetivo de este estudio ha sido evaluar el comportamiento del maíz híbrido para ensilaje en diferentes condiciones de sucesión de culturas en la ciudad de Umuarama - PR. El experimento se llevó a cabo en dos áreas diferentes de la granja experimental de la Universidad Paranaense - Unipar, en el referido municipio. En el área 1 se ha cultivado maíz en sucesión a la caña de azúcar y en el área 2, en sucesión al pasto del género Brachiaria. El experimento se llevó a cabo en el periodo de diciembre/2014 a abril/2015. Se utilizó el maíz híbrido 2B688 PW, cuyas prácticas culturales se realizaron como las necesidades de los cultivos. Después de 78 días de la siembra, se tomaron muestras al azar, 19 parcelas de 8m² en cada área, que evaluó altura de las plantas y la inserción de mazorca, longitud y diámetro de mazorca. No se encontraron diferencias significativas entre los tratamientos para todas las variables, mostrando que el maíz presentó las mismas respuestas cuando cultivado en sucesión a la caña o al pasto de Brachiaria.

La irrigación con levaduras incrementa el contenido nutricional del forraje verde hidropónico de maíz / Yeast irrigation enhances the nutritional content in hydroponic green maize fodder

El objetivo del presente estudio fue evaluar el efecto de la irrigación con las levaduras Debaryomyces hansenii var. Fabry, Yarowia lipolytica YIBCS002, Yarowia lipolytica var. BCS y Candida pseudointermedia sobre el contenido nutricional final del forraje verde hidropónico de maíz (Zea mays L. ), al ser efectuada en diferentes etapas de crecimiento de aquel (fase semilla-plántula o fase plántula-planta 20 cm), o bien durante todo el cultivo. Todas las levaduras incrementaron el contenido de proteína cruda, lípidos, cenizas, humedad y energía bruta, independientemente de la etapa de crecimiento del forraje en las que fueron aplicadas. El porcentaje de electrólitos (Na, K, Cl, sulfatos, Ca y Mg) varió en función de la levadura aplicada; D. hansenii incrementó todos los electrólitos, excepto el P. Se concluye que la adición de levaduras del género Debaryomyces, Candida y Yarowia en la solución de riego de sistemas hidropónicos mejora el contenido de nutrientes del forraje verde. Esta práctica puede contribuir a la generación de cultivos de valor comercial en espacios limitados

The objective of this study was to evaluate the effect of irrigation with yeasts (Debaryomyces hansenii var. Fabry, Yarowia lipolytica YIBCS002, Yarowia lipolytica var. BCS and Candida pseudointermedia) on the final nutritional content of hydroponic green maize fodder (Zea Zea mays L.), applied at different fodder growth stages (1. seed-seedling stage, 2. seedling-plant 20 cm, 3. during all the culture). Irrespective of the fodder growth stages at which they were applied, all yeasts tested enhanced the content of raw protein, lipids, ash, moisture and energy. The percentage of electrolytes (Na, K, Cl, sulphates, Ca and Mg) showed different responses depending on the kind of yeast applied; D. hansenii exhibited the highest increment in all electrolytes, except for phosphorous. We conclude that the addition of yeasts belonging to the genera Debaryomyces, Candida and Yarowia to the irrigation solution of hydroponic systems enhances the nutrient content of green fodder. This kind of irrigation can be applied to generate high commercial value cultures in limited spaces.

Divergência genética de milho transgênico em relação à produtividade de grãos e à qualidade nutricional / Genetic divergence of transgenic maize in relation to grain productivity and nutritio nal quality

O objetivo deste trabalho foi verificar a divergência genética entre genótipos de milho transgênico, em relação à produtividade de grãos e à qualidade nutricional. O experimento foi conduzido na safra 2009/2010, em Santa Maria, Estado do Rio Grande do Sul, no delineamento blocos casualizados, com três repetições. Foram avaliados 18 genótipos e mensuradas as seguintes variáveis após a colheita: produtividade de grãos, proteína bruta, lisina, metionina, cisteina, treonina, triptofano, valina, isoleucina, leucina, fenilalanina, histidina, arginina, extrato etéreo, amido e amilose. Para cada variável, foi realizada a análise de variância e comparadas as médias por meio do teste de Scott-Knott. Foi determinada a matriz de coeficientes de correlação genotípica e realizado o diagnóstico de multicolinearidade. Foi determinada a matriz de dissimilaridade entre os genótipos por meio da distância generalizada de Mahalanobis, realizado o agrupamento dos genótipos por meio do método UPGMA e validado o agrupamento por meio do coeficiente de correlação cofenética. Foram comparadas as médias dos grupos por meio do teste t para amostras independentes. Há divergência genética entre os genótipos de milho transgênico. As variáveis amilose, extrato etéreo e cisteina foram, nessa ordem, as que mais contribuíram para a divergência genética. Com base na produtividade de grãos, proteína bruta, lisina, cisteina, triptofano, extrato etéreo e amilose, há quatro grupos de genótipos de milho transgênico.

The aim of this study was to investigate the genetic divergence between genotypes of transgenic maize, in relation to grain productivity and nutritional quality. The experiment was conducted in 2009/2010 in Santa Maria, State of Rio Grande do Sul, on randomized block design with three replicates. Eighteen genotypes were analyzed and the variables were measured after harvest: grain productivity, crude protein, lysine, methionine, cysteine, threonine, tryptophan, valine, isoleucine, leucine, phenylalanine, histidine, arginine, ethereal extract, starch and amylose. An analysis of variance was performed for each variable and the means were compared using the Scott-Knott test. The genotypic correlation matrix was calculated, multicollinearity was evaluated and a contribution analysis was performed. Dissimilarity matrix between genotypes was determined by Mahalanobis generalized distance. The genotypes were grouped using the Unweighted Pair Group Method with Arithmetic Mean (UPGMA) and the cophenetic correlation coefficient was calculated to validate the grouping. The group means were compared using the t-test for independent samples. There is genetic divergence between genotypes of transgenic maize. Variables amylose, ethereal extract and cysteine showed the greatest contribution to genetic divergence. Based on grain productivity, crude protein, lysine, cysteine, tryptophan, ethereal extract and amylase, there are four genotype groups of transgenic maize.

Chromium accumulation potential of Zea mays grown under four different fertilizers.

Chromium (Cr) contamination in soil is a growing concern in sustainable agriculture production and food safety. We performed pot experiment with chromium (30 mg/ soil) to assess the accumulation potential of Zea mays and study the influence of four fertilizers, viz. Farm Yard Manure (FYM), NPK, Panchakavya (PK) and Vermicompost (VC) with respect to Cr accumulation. The oxidative stress and pigment (chlorophyll) levels were also examined. The results showed increased accumulation of chromium in both shoots and roots of Zea mays under FYM and NPK supply, and reduced with PK and VC. While the protein and pigment contents decreased in Cr treated plants, the fertilizers substantiated the loss to overcome the stress. Similarly, accumulation of Cr increased the levels of antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) indicating the enhanced damage control activity. However, these levels were relatively low in plants supplemented with fertilizers. Our results confirm that the maize can play an effective role in bioremediation of soils polluted with chromium, particularly in supplementation with fertilizers such as farm yard manure and NPK.

Pre-treatment of seeds with static magnetic field ameliorates soil water stress in seedlings of maize (Zea mays L.).

The effect of magnetic field (MF) treatments of maize (Zea mays L.) var. Ganga Safed 2 seeds on the growth, leaf water status, photosynthesis and antioxidant enzyme system under soil water stress was investigated under greenhouse conditions. The seeds were exposed to static MFs of 100 and 200 mT for 2 and 1 h, respectively. The treated seeds were sown in sand beds for seven days and transplanted in pots that were maintained at -0.03, -0.2 and -0.4 MPa soil water potentials under greenhouse conditions. MF exposure of seeds significantly enhanced all growth parameters, compared to the control seedlings. The significant increase in root parameters in seedlings from magnetically-exposed seeds resulted in maintenance of better leaf water status in terms of increase in leaf water potential, turgor potential and relative water content. Photosynthesis, stomatal conductance and chlorophyll content increased in plants from treated seeds, compared to control under irrigated and mild stress condition. Leaves from plants of magnetically-treated seeds showed decreased levels of hydrogen peroxide and antioxidant defense system enzymes (peroxidases, catalase and superoxide dismutase) under moisture stress conditions, when compared with untreated controls. Mild stress of -0.2 MPa induced a stimulating effect on functional root parameters, especially in 200 mT treated seedlings which can be exploited profitably for rain fed conditions. Our results suggested that MF treatment (100 mT for 2 h and 200 for 1 h) of maize seeds enhanced the seedling growth, leaf water status, photosynthesis rate and lowered the antioxidant defense system of seedlings under soil water stress. Thus, pre sowing static magnetic field treatment of seeds can be effectively used for improving growth under water stress.

Modificación del Almidón de maiz y sus efectos en el tratamiento de niños con glucogenosis / Modification of starch corn and its effects on the treatment of children with glycogenosis

Introducción: El almidón de maíz (AM) está indicado en el manejo de niños con glucogenosis hepática (GH).Objetivo: Describir la respuesta clínica en siete niños con GH I y III, del Hospital Pablo Tobón Uribe de Medellín, Colombia, al cambiar el AM de uso alimenticio (UA), por AM de pureza farmacológica (PF). Metodología: Estudio observacional, retrospectivo, descriptivo realizado en 51 meses en el que se comparan pruebas bioquímicas y evolución clínica de siete niños ambulatorios con GH, quienes recibían AMUA y se les cambió a AMPF, por recaída en sus controles bioquímicos, relacionados con el cambio en la composición del AM tradicional, al que se le adicionó una mezcla de vitaminas y minerales. Resultados: Se incluyeron 3 niñas y 4 niños entre 13 y 148 meses, 3 con GH I y 4 con GH III, que recibían AMUA, y luego de cambiar a AMPF, presentaron mejoría clínica y bioquímica así: glucemia en ayunas de 77 mg/dL (48-90) a 85 (68-119) mg/dL, ALT de 390 U/L (47-1410) a 159 (47-345) U/L y triglicéridos de 487 (186-1797) mg/dL a 240 (112-614) mg/dL.Conclusiones: El AMPF en niños con GH I y III, demostró resultados mejores, que los obtenidos con el AMUA. La evidencia bioquímica y clínica, permite recomendar su utilización en el tratamiento actual de los pacientes con estos tipos de GH.

Introduction: Corn starch (CS) is indicated for the management of children with liver glucogenosis (LG). Objective: To describe the clinic outcome in 7 children with LG I and III, from Hospital Pablo Tobón Uribe from Medellín, Colombia, to change food (F) CS by the pharmacological purity (PP) CS. Methods: Observational, retrospective, descriptive study performed in 51 months comparing biochemical and clinical course of 7 children outpatient with LG, those receiving FCS and were switched to PPCS by relapse in biochemical controls related to the change in the composition of the traditional commercial CS, which was added a mixture of vitamins and minerals. Results: Were included 3 girls and 4 boys between 13 and 148 months, 3 with LG I and 4 with LG III, receiving FCS, and after switching to PPCS, they improved the biochemical tests and clinical status. Conclusions: PPCS in children with LG I and III, showed better results than those obtained with FCS. The biochemical and clinical evidence both to recommend its use in the current treatment of patients with these types of LG.

Growth response of maize plantlets inoculated with Enterobacter spp., as a model for alternative agriculture / Respuesta de plántulas de maíz inoculadas con Enterobacter spp. como un modelo de agricultura alternativa

A maize rhizosphere isolate was phenotypically and genotypically characterized and identifed as Enterobacter spp. bacterium. Germinated seeds were inoculated, the plantlets were sown in vermiculite and in soil and grown under laboratory and feld conditions, respectively. The adherence, colonization and plant growth promotion capability of Enterobacter sp. UAPS03001 was evaluated in "Rojo-Criollo" maize under laboratory conditions. Twenty days after inoculation, the treated plantlets showed larger biomass than non-inoculated ones. In feld grown plants, the kernel biomass was also greater in inoculated than in non-inoculated plants. The inoculation of maize sprouts with plant growth- promoting bacteria before their sowing in the feld would be an alternative practice for achieving successful yield in temporal agriculture.

En este trabajo se aisló una bacteria de la rizósfera de maíz, que fue caracterizada mediante métodos fenotípicos y genotípicos e identifcada como Enterobacter sp. UAPS03001. La bacteria fue inoculada en semillas de maíz "Rojo-Criollo" germinadas en forma axénica. Las semillas germinadas e inoculadas se plantaron en vermiculita y posteriormente las plántulas fueron cultivadas en vermiculita o en suelo, para evaluar el efecto promotor del crecimiento vegetal de dicha bacteria, bajo condiciones de laboratorio y de campo. Bajo condiciones de laboratorio, también se evaluó la capacidad de esta cepa para adherirse a las plantas de maíz y colonizarlas. Veinte días después de la inoculación, las plántulas inoculadas mostraron una biomasa mayor con referencia a las no inoculadas. En campo, la biomasa de la mazorca fue también mayor en las plantas inoculadas respecto de las plantas no inoculadas. La inoculación de germinados de maíz con una bacteria promotora del crecimiento vegetal y su posterior transferencia a campo podría ser una práctica alternativa para llevar a cabo una producción exitosa en agricultura de temporal.

Efecto de diferentes concentraciones de ácido antranílico en el crecimiento del maíz / The effect of different anthranilic acid concentrations on maize growth

La rizobacteria Azospirillum brasilense basa su capacidad promotora del crecimiento vegetal en la producciónde auxinas y otras hormonas, entre ellas el ácido antranílico (AA). En este trabajo se determinó el efectodel AA (0, 500, 1000, 3000 y 5000 ppm) en el crecimiento y la acumulación de biomasa del híbrido de maíz83G66 en condiciones de invernadero. El AA de 500 a 3000 ppm promovió un mayor crecimiento (área foliary altura de planta), y el AA de 1000 y 3000 ppm incrementó significativamente la biomasa seca en maíz encomparación con el testigo. El 90% de la asimilación del AA en las plantas ocurrió durante los primeros 10días después del tratamiento.

The plant growth-promoting ability of rhizo-bacterium Azospirillum brasilense is based on production of auxins and other hormones, among them outstanding antranilic acid (AA). In this work we determined the antranilic acid (0, 500, 1000, 3000, and 5000 ppm) effects on maize growth and dry biomass accumulation under greenhouse conditions using the hybrid 83G66. From 500 to 3000 ppm of AA significantly increased plant growth (leaf area and plant height) while 1000 and 3000 ppm of AA significantly increased dry biomass accumulation in maize compared with control (0 ppm). The 90 % of AA in maize plants was assimilated during the early 10 days after treatment.

Genetic diversity of breeding popcorn lines determined by SSR markers / Diversidad genética de líneas de mejoramiento del Zea mays determinada por marcadores SSR

Information about genetic dissimilarity is very important to corroborate genealogical relationships and to predict the most heterozygotic hybrid combinations. Eight popcorn S6 lines of diverse germplasm types were evaluated using simple sequence repeats (SSR) markers. Of a total of 51 evaluated polymorphic primers, 15 were used for polymerase chain reaction (PCR) amplification. The genetic distance was estimated by Rogers’ modified distance. The different popcorn breeding programs in Brazil are possibly using highly similar base-populations. The genetic similarity of lines P1-3 and P8-1 was lowest, while P3-3 and P8-2 were genetically more similar. The cophenetic correlation showed that the Unweighted Pair-Group Method Using Arithmetic Averages (UPGMA) was reliable to discriminate the genotypes in five groups. The clusters were consistent with the estimates of genetic identity. There was a moderate coincidence degree between the groups and genealogy of lines. Higher levels of heterozygosity are expected from crosses between the group containing lines P3-3 and P7-3 with that of P1-3 and P7-4. Crosses between lines P1-3 and P8-1 are also promising.

Methodological development of a quality index for agricultural operations, for corn cultivation using multi-criterion analysis

One of the major problems in the Brazilian agriculture is related to the production loss in the field, which, due to many factors, is not being considered. This article has the objective to develop a methodology to identify a quality index which integrates some crop quality variables which are able to indicate how the crop is developing in terms of loss in the field. The results have showed that the strategy of multi-criterion analysis and Fuzzy logic proved to be important tools for the assessment and preparation of a quality index for corn production. The index proposed performed well in representing the quality of agricultural operations when compared with reality.

Um dos maiores problemas na agricultura brasileira refere-se à perda da produção no campo que, devido a vários fatores, não é considerada. Este artigo tem o objetivo de desenvolver uma metodologia para identificar um índice de qualidade que integre algumas variáveis qualitativas da cultura que são capazes de mostrar como está o desenvolvimento em termos de perda no campo. Os resultados mostraram que a análise de multicritério e lógica fuzzy são ferramentas importantes na verificação e confecção de um índice de qualidade de perdas, para a cultura do milho. O índice calculado representou bem a qualidade das operações agrícolas, quando comparado com a realidade.

Characterization of water binding and germination traits of magnetically exposed maize (Zea mays L.) seeds equilibrated at different relative humidities at two temperatures.

A study was undertaken to characterize the water sorption properties and enhancement in germination and seedling vigour of maize (Zea mays L.) seeds exposed to static magnetic fields of 100 mT and 200 mT for 2 and 1h, respectively. Water sorption isotherms were constructed for magnetically- exposed and unexposed seeds by equilibrating over different saturated salt solutions at 25 and 35°C. The germination and vigour parameters were evaluated for magnetically-exposed and unexposed seeds, equilibrated over the wide range of relative humidities (RHs) at 25 and 35°C. Moisture content increased with increase in RH and decreased with increase in equilibrium temperature. The germination and vigour reduced at high and very low humidities. Magnetically-exposed seeds maintained higher germination and vigour at both temperatures and all RHs, indicating the better quality of magnetically- exposed seeds. The leachate conductivity of magnetically-exposed seeds was lower than unexposed seeds at all RHs, suggesting better membrane integrity in magnetically-exposed seeds. Analysis of the isotherms using D’Arcy-Watt equation revealed that irrespective of the temperature, in magnetically-treated seeds weak binding sites were more and strong and multi-molecular binding sites were less compared to the unexposed seeds. Total binding sites were more in unexposed control seeds. The modification of binding properties of seed water and increased seed membrane integrity in magnetically-exposed seeds might have enhanced the germination traits and early seedling growth of maize.

Genetic distance estimates among single cross hybrids and correlation with specific combining ability and yield in corn double cross hybrids

The objective of the present study was to correlate the genetic distances (GD) of single cross hybrids with yield, heterosis and specific combining ability (SCA) in the double cross hybrid synthesis. For this, 10 single cross commercial hybrids were used from different companies, and all the possible double hybrids were synthesized by a complete dialell. The hybrids were assessed in 15 locations in the 2005/2006 agricultural season, using the randomized complete block design with three repetitions. DNA was extracted from the single cross hybrids and 20 simple sequence repeat primers were used, nine of which were linked to the quantitative trait loci. It was ascertained that the single hybrids were superior in general to the double cross hybrids and that yield was highly correlated with heterosis and SCA (r = 0.75 and 0.82, respectively). There was no significant correlation between yield and GD (r = 0.25), but this index was at the limit of significance. There was a medium correlation between GD and heterosis (r = 0.40) and GD and SCA (r = 0.38). The intergroup hybrids placed by genetic grouping were generally more productive than intragroup hybrids, and the hybrids with GD greater than 0.84 had the maximum heterosis and SCA. It was concluded that the markers were efficient in placing hybrids in different heterosis groups and were also useful in eliminating the most negative heterosis and SCA.