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Chilean Journal of Agricultural & Animal Sciences
Number of Followers: 1  

  This is an Open Access Journal Open Access journal
ISSN (Print) 0719-3882 - ISSN (Online) 0719-3890
Published by SciELO Homepage  [911 journals]
  • SELECTION OF STRAINS OF Beauveria bassiana AND Metarhizium anisopliae
           (ASCOMYCOTA: HYPOCREALES) FOR ENDOPHYTIC COLONIZATION IN COCONUT SEEDLINGS
           

    • Abstract: RESUMEN Beauveria bassiana y Metarhizium anisopliae son considerados patógenos virulentos contra el picudo Rhynchophorus palmarum. El objetivo de este estudio fue determinar la habilidad de la cepa comercial Beauveriplant SBb36 de B. bassiana y la cepa JGVM1 de M. anisopliae, para establecer una relación endofítica con plantas de coco Cocos nucifera (Linnaeus) obtenidas a partir de semilla sexual y de cultivo de tejidos. Se evaluaron diferentes métodos de inoculación: aspersión foliar, inyección en tallo y aplicación de suspensión conidial en las raíces, fueron usados para inocular plantas obtenidas a partir de semilla sexual, mientras que el método de inmersión fue usado para inocular plantas obtenidas a partir de cultivo de tejidos. El porcentaje de colonización en diferentes tejidos de las plantas se determinó a través del re-aislamiento de los hongos cuatro semanas después de la inoculación. Las cepas Beauveria bassiana (Beauveriplant SBb36) y Metarhizium anisopliae (JGVM1) colonizaron endofíticamente el 100% de las plantas de coco obtenidas a partir de cultivo de tejidos y el 91.6% de las plantas de coco obtenidas por semilla sexual. En el presente estudio, se reporta por primera vez que B. bassiana and M. anisopliae establecen una relación de endofitismo con plántulas de coco obtenidas a partir de la germinación de semilla sexual y cultivo de tejidos a través de inoculaciones dirigidas.ABSTRACT Beauveria bassiana and Metarhizium anisopliae are considered virulent pathogens of the coconut weevil Rhynchophorus palmarum (Linnaeus). The objective of this study was to determine the ability of B. bassiana (Beauveriplant SBb36) and M. anisopliae (JGVM1) to establish an endophytic relationship with coconut Cocos nucifera (Linnaeus) seedlings. Strains were selected based on the mortality of adults of R. palmarum exposed to these fungi. Three methods of inoculation were used to inoculate the seedlings obtained through seed germination: foliar spray, stem injection and drench to the roots. Immersion of seedlings in a conidial suspension was used to inoculate seedlings obtained from tissue culture. Colonization was determined through the re-isolation of the fungi four weeks after inoculation. Beauveriplant SBb36 and JGVM1 colonized endophytically 100% of the seedlings obtained through tissue culture and 91.6% of seedlings obtained from germinated seeds. For plants inoculated by immersion with B. bassiana, the colonization rate in petioles (43%) was higher than in leaves and roots, 14 and 17%, respectively. Metarhizium anisopliae did not show significant differences in the colonization rate in leaves, petioles and roots. Plants inoculated by foliar spraying showed that colonization was higher in leaves > petioles > stems > roots. Colonization in stem injection was higher in stems than in the roots. Soil drench inoculation was higher in roots > stems. To our knowledge, this is the first report describing the endophytic relationship that B. bassiana and M. anisopliae establish with coconut seedlings obtained through seed germination and tissue culture when targeted inoculations are performed.
       
  • SPATIAL DEPENDENCE OF SOIL POTENTIALLY AVAILABLE NITROGEN IN TWO
           CONTRASTING SITES

    • Abstract: RESUMEN La alta variabilidad del nitrógeno (N) en el suelo afecta la aplicación efectiva de fertilizantes nitrogenados. El objetivo de esta investigación fue determinar y evaluar la dependencia espacial del N en dos tipos de suelo. Para ello se utilizó un diseño espacial anidado optimizado, con 16 estaciones de muestreo, y en direcciones aleatorias se tomaron muestras de suelo (0-23 cm) a intervalos de distancia de 1,5; 4,5; 13,5; 40,5; y 121,5 m. Los suelos evaluados fueron un Andisol y un Inceptisol (2 x n = 98), en los que se midió el potencial de nitrógeno disponible (PND) a través de incubación anaeróbica de suelo por 7 días a 40oC (PND = NH4+ día 7 - NH4+ día 1). La dependencia espacial del PND en cada uno de los sitios fue establecida mediante la acumulación de varianza de cada distancia, calculada a través de un análisis de máxima probabilidad residual (REML), y posterior aproximación al variograma. Los resultados mostraron un rango amplio de valores en ambos sitios. El sitio Andisol registró un elevado PND, con un valor promedio de 32,92 mg NH4+ kg-1, cinco veces mayor que en el Inceptisol, lo que se explicó principalmente por un mayor contenido de materia orgánica. La dependencia espacial del PND para ambos sitios se obtuvo a intervalos de 13,5 y 40,5 m, logrando cuantificar un 59% de la variabilidad del proceso en el sitio Andisol, y tan sólo un 35% en el sitio Inceptisol.ABSTRACT Soil nitrogen (N) variability affects the effective application of N fertilizers. The objective of this research was to determine and assess the spatial dependence of soil N in two different soils using spatial sampling and geostatistics fundamentals. An optimized nested sampling design was applied in two sites, using 16 main stations from where soil samples (0 - 23 cm) were obtained at 1.5, 4.5, 13.5, 40.5, and 121.5 m, at random directions. Soil samples were collected from an Andisol and an Inceptisol (2 x n = 98), and the potentially available N (PAN) was measured by anaerobic soil incubation for 7 days at 40oC (PAN = NH4+ day 7 - NH4+ day 1). The PAN variance components from each distance were calculated by residual maximum likelihood (REML), and then accumulated to plot an approach to the variogram. The results showed a wide range of values for PAN at both sites. The Andisol site registered high PAN levels, with a mean value of 32.92 mg NH4+ kg soil-1, which was five times larger than in the Inceptisol soil, probably associated with a larger soil organic matter content. The limit of the spatial dependence was 13.5 m for the Andisol, and 40.5 m for the Inceptisol soil, corresponding to the 59% and 35% of the process variance, respectively.
       
  • DYNAMICS OF CHILEAN FRUIT EXPORTS FROM A REGIONAL PERSPECTIVE (2008-2018)

    • Abstract: RESUMEN Las exportaciones de productos silvoagropecuarios, particularmente las exportaciones de fruta, son uno de los pilares de la economía chilena. En general, el estudio de este tipo de exportaciones en Chile se ha realizado desde una perspectiva nacional, a pesar de la gran diversidad de las condiciones agroclimáticas nacionales. El objetivo del presente artículo es caracterizar la evolución y dinámicas de las exportaciones frutícolas chilenas en la última década, pero desde una perspectiva regional. Para ello se utilizó información de fuentes oficiales, la cual se analizó mediante técnicas de estadística descriptiva y la construcción de diversos índices. Los resultados obtenidos muestran que las exportaciones de fruta se concentran en la zona central del país, donde las regiones tienen una mayor participación, así como también una importante oferta de productos frutícolas ofrecidos a diferentes mercados internacionales.ABSTRACT Forest and agricultural exports, particularly fruit exports, are one of the backbones of the Chilean economy. In general, the study of this type of exports has been approached from a local perspective, regardless of the great diversity of agroclimatic conditions in the country. The objective of this article is to characterize the evolution and dynamics in of Chilean fruit exports the last decade from a regional perspective. For this, data were obtained from official sources and analyzed using descriptive statistics techniques and various indexes. The results obtained show that fruit is mainly exported from the central area of the country, where the regions have a greater share of the exports and also an important offer of fruits exported to different international markets.
       
  • Predation of Nabis punctipennis on Acyrthosiphon pisum in the presence of
           the alternative prey Aphis craccivora in alfalfa

    • Abstract: ABSTRACT The feeding behavior of the generalist predator Nabis punctipennis Blanchard (Nabidae) on Acyrthosiphon pisum Harris (Aphididae), two hemipterans common in alfalfa in Chile, was studied in a laboratory experiment using A. pisum, and Aphis craccivora Koch (Aphididae) as alternative prey, which is another common aphid in alfalfa. The presence of A. craccivora did not affect the predation of A. pisum by N. punctipennis. This finding on the predatory behavior of N. punctipennis is valuable to evaluate the potential of this nabid as a biological control agent of A. pisum.RESUMEN Se estudió la conducta de alimentación del depredador generalista Nabis punctipennis Blanchard (Nabidae) sobre Acyrthosiphon pisum Harris (Aphididae), dos hemípteros comunes en alfalfa en Chile, mediante un experimento en laboratorio utilizando A. pisum y Aphis craccivora Koch (Hemiptera: Aphididae) como presa alternativa, otro áfido común en alfalfa. La presencia de A. craccivora no afectó la depredación de A. pisum por N. punctipennis. La información obtenida sobre la conducta de depredación de N. punctipennis es valiosa para evaluar su potencial como agente de control biológico de A. pisum.
       
  • DIVERSITY OF ANTS (HYMENOPTERA: FORMICIDAE) INSIDE AND OUTSIDE HIVES OF
           THE WESTERN HONEY BEE APIS MELLIFERA L. (HYMENOPTERA: APIDAE), JUJUY,
           ARGENTINA

    • Abstract: ABSTRACT Ants are frequent visitors to Apis mellifera L. hives. Certain species may cause serious loss of productivity to apiculture. The objective of this study was to describe the diversity and abundance of ants both outside and inside the hives of Apis mellifera L. in Valles Templados, Jujuy province, Argentine. Ants were collected by hand and pitfall traps in the Spring and Summer season of 2016, 2017 and 2018, in apiaries found at three different localities of Valles Templados: Río Blanco, Tilquiza and Severino. Pitfall trapping resulted in 824 specimens belonging to 10 species in Severino, 208 individuals of 9 species in Tilquiza, and 289 individuals of 2 species in Río Blanco. The most common ant species found were: Pheidole sp. (56.07%), Linepithema humile (94.81%), and Solenopsis sp. (56.73%) in Severino, Rio Blanco and Tilquiza, respectively. The hand collection of ants yielded 248 individuals of 7 species collected in Severino, 35 individuals of 3 species in Tilquiza, and 294 individuals of 2 species in Río Blanco. The most common species was Linepithema humile 67.3%. The abundance figures showed significant differences among sampling sites. Several species collected by hand were the same as those collected with pitfall traps at the three localities. This study provides information about the taxonomic composition of Formicidae associated with Apis mellifera L. in Valles Templados in Jujuy. It also provides valuable information on the effect of ants on bee hives, which enables to develop control measures where necessary.
       
  • NATIVE STRAINS OF Bacillus thuringiensis AGAINST Spodoptera frugiperda and
           Alabama argillacea IN COTTON CROP (Gossypium barbadens) IN PIURA, PERU

    • Abstract: RESUMEN Los lepidópteros son una de las plagas más importantes del algodón (Gossypium barbadens). Su control se realiza con insecticidas sintéticos, que contaminan el medio ambiente, por lo que el control biológico constituye una alternativa ecológica al uso de tales productos químicos. El objetivo de esta investigación fue aislar cepas nativas de Bacillus thuringiensis (Bt) y evaluar su toxicidad contra Spodoptera frugiperda y Alabama argillacea, insectos plaga del cultivo de algodón. Las cepas nativas de Bt fueron aisladas de muestras de suelo de diferentes zonas algodoneras de Piura, Perú. Se obtuvieron 600 colonias del género Bacillus, de los cuales 37 cepas nativas presentaron características morfológicas similares a las cepas estándares de Bt (HD1 y NA118). La caracterización morfológica y bioquímica de las 37 cepas nativas mostró que 15 cepas presentaron cristal paraesporal de forma bipiramidal de acción tóxica contra lepidópteros, y características bioquímicas similares a las cepas estándares de Bt. El efecto tóxico de las 15 cepas nativas se evaluó con la prueba del alimento contaminado con discos de hojas de lechuga y algodón. Los resultados mostraron que las cepas IN-24, IN-30 e IN-34 ocasionaron 100% de mortalidad en S. frugiperda y las cepas IN-19, IN-24 e IN-25 ocasionaron 100% de mortalidad en A. argillacea, mientras que la cepa IN-24 ocasionó 100% de mortalidad en ambas especies. Por otra parte, la prueba de la dieta artificial reveló que las cepas IN-34, IN-01 e IN-31 ocasionaron los mayores porcentajes de mortalidad en S. frugiperda y A. argillacea, respectivamente. Se concluyó que existe varias cepas nativas de B. thuringiensis que pueden controlar S. frugiperda y A. argillacea.ABSTRACT The order Lepidoptera is one of the most important pests of cotton (Gossypium barbadens). These insects are controlled with synthetic insecticides, which contaminate the environment. Therefore, biological control is an environmentally friendly alternative to the use of such chemicals. The objective of this research was to isolate native strains of Bacillus thuringiensis (Bt) and evaluate their toxicity against Spodoptera frugiperd a and Alabama argillacea, which are insect pests of the cotton crop. The native strains of Bt were isolated from soil samples from different cotton areas of the Piura, Perú. 600 colonies of the genus Bacillus were obtained, of which 37 native strains presented morphological characteristics similar to the standard strains of Bt (HD1 and NA118). The morphological and biochemical characterization showed that 15 strains showed parasporal crystal of bipyramidal form of toxic action against Lepidoptera, exhibiting biochemical characteristics equal to the standard strains of Bt. The toxic effect of these 15 native strains was evaluated through a food poisoned test using lettuce and cotton leaf discs. The results showed that strains IN-24, IN-30 and IN-34 caused 100% mortality in S. frugiperda; strains IN-19, IN-24 and IN-25 caused 100% mortality in A. argillacea; while strain IN-24 caused 100% mortality in both species. The artificial diet test showed that strains IN-34, IN-01 and IN-31 caused the highest mortality rates in S. frugiperda and A. argillacea, respectively, when compared with the standard strains HD1 and NA118. It is concluded that there are several native strains of B. thuringiensis that can control S. frugiperda and A. argillacea.
       
  • GENETIC VARIABILITY PARAMETERS OF CERTIFIED HOLSTEIN CATTLE IN CUENCA
           DISTRICT, ECUADOR

    • Abstract: RESUMEN La raza Holstein es la que más contribuye a la producción láctea en Ecuador. Sin embargo, no existen datos de parámetros genéticos que describan las características de los hatos lecheros del país. Por ello, el objetivo de este trabajo fue analizar la variabilidad genética de bovinos registrados de la raza Holstein en el cantón Cuenca, Ecuador. Para ello se analizaron los marcadores microsatélites CSRM60, INRA083, CSSM66, ETH3, HEL9, TGLA53, BM1818, LSTS006, BM2113, ETH225, TGLA122, ETH10, TGLA227, INRA032 y SPS115 en 52 bovinos, de acuerdo a lo sugerido por la FAO para la caracterización genética de poblaciones de animales domésticos. Se encontró en promedio 8,4 ± 1,88 alelos y una frecuencia de 0,08 ± 0,056 de alelos nulos. Los valores de heterocigosidad observada y esperada alcanzaron 0,68 ± 0,13 y 0,82 ± 0,07, respectivamente. El contenido de información polimórfica osciló entre 0,70 y 0,88, y el coeficiente de endogamia varió entre -0,38 y 0,45. De los 15 locis analizados, solamente el CSSM66 presentó equilibrio Hardy-Weinberg, y 4 de ellos mostraron un alto nivel de endogamia. Se concluye que los loci estudiados muestran una alta variabilidad genética y alto polimorfismo. Esto ofrece amplia información para los estudios de paternidad e identidad. No obstante, de acuerdo al nivel de consanguinidad debe considerarse la selección de una alta diversidad de toros para los programas de inseminación artificial.ABSTRACT Holstein cattle account for most of the dairy production in Ecuador. However, there are no data on genetic parameters that describe the characteristics of the country's dairy herds. Therefore, the objective of this study was to analyze the genetic variability of registered Holstein cattle in Cuenca district, Ecuador. For this, the microsatellite markers CSRM60, INRA083, CSSM66, ETH3, HEL9, TGLA53, BM1818, LSTS006, BM2113, ETH225, TGLA122, ETH10, TGLA227, INRA032 and SPS115 were analyzed in 52 bovines, according to the guidelines on genetic characterization of domestic animal species suggested by FAO. It was found an average of 8.4 ± 1.88 alleles and a frequency of 0.08 ± 0.056 of null alleles. The observed and expected heterozygosity values reached 0.68 ± 0.13 and 0.82 ± 0.07, respectively. The polymorphic information content ranged between 0.70 and 0.88, while the inbreeding coefficient varied between -0.38 and 0.45. Of the 15 loci analyzed, only CSSM66 had a Hardy-Weinberg equilibrium and 4 of them showed a high level of inbreeding. It is concluded that the loci studied show high genetic variability and polymorphism. This provides ample information for paternity and identity studies. However, according to the consanguinity level, high genetic diversity should be considered when selecting bulls for artificial insemination programs.
       
  • GENETIC DIVERSITY ASSESSED BY PEDIGREE ANALYSIS IN THE BLANCO OREJINEGRO
           (BON) CATTLE BREED POPULATION FROM THE COLOMBIAN GERMPLASM BANK

    • Abstract: ABSTRACT The Blanco Orejinegro (BON) breed is one of the seven Colombian Creole cattle breeds, which descends directly from Spanish cattle brought to the Americas during the conquest period. Currently, most of the Creole cattle breeds in Colombia are at risk of disappearing due to the use of foreign breeds and absorbent crosses towards the Zebu and because of this, a germplasm bank was created to preserve them. The BON population kept in this germplasm bank has remained as a closed nucleous over time, and this can affect the conservation of its genetic variability. The objective of this study was to characterize the genetic structure of the BON population maintained in the germplasm bank using pedigree analysis. Genealogical information collected between 1980 and 2019 was used to estimate generational interval, level of pedigree integrity, inbreeding, and its evolution over time. The animals born between 2015 and 2019 were selected as the reference population to estimate the effective population size and parameters derived from the genetic origin probability. The average generation interval for the period studied was 4.58 years, and the general inbreeding was 1.32%. For the reference population, the inbreeding was 2.88%, and the effective population size was 123.75, while the effective number of founders and ancestors was 55 and 38, respectively. The results indicate that the population has a good genetic diversity and low levels of inbreeding. The use of a larger number of breeder males is recommended to conserve the population over time.
       
  • AMARANTHUS CRUENTUS L. AS A FOOD ALTERNATIVE IN LAYING HENS TO
           REDUCE CHOLESTEROL IN EGGS

    • Abstract: ABSTRACT Amaranth (Amaranthus cruentus L.) is a food high in protein and lysine content, and has a well-balanced amino acid composition. In addition, it has shown to be efficient in lowering egg cholesterol. The objective of this study was to evaluate the effect of different inclusion levels of Amaranthus cruentus L. in the diet of laying hens, on egg cholesterol content and production parameters. 200 laying hens of 30 weeks of age were fed on diets that included 0, 15, 30 and 45% (dry matter basis) of A. cruentus. For 2 months, weekly feed intake per hen, egg production per week, egg mass and feed conversion ratio were evaluated. 480 eggs were analyzed to determine cholesterol content by high performance liquid chromatography. The results were analyzed by analysis of variance for a randomized block design. The inclusion of 15% of A. cruentus seeds in the diet decreased egg yolk cholesterol content without significantly affecting the main production parameters.RESUMEN El amaranto (Amaranthus cruentus L.) es un alimento de alto aporte en proteína, lisina y buen balance de aminoácidos. Además, ha demostrado ser eficiente para disminuir el colesterol del huevo. El objetivo de este estudio fue evaluar el efecto de diferentes niveles de inclusión de A. cruentus L. en la dieta de aves de postura, sobre el contenido de colesterol en el huevo y parámetros productivos. Se realizó un experimento con 200 gallinas Hy Line de postura de 30 semanas de vida, para evaluar la inclusión de A. cruentus en proporciones de 0, 15, 30 y 45% base materia seca. Durante 2 meses se evaluó el consumo semanal de alimento por ave, producción de huevos por semana, masa de huevo y conversión de alimento; 480 huevos fueron analizados para determinar el contenido de colesterol mediante cromatografía liquida de alto rendimiento. Los resultados fueron analizados mediante análisis de varianza en diseño de bloques al azar. La inclusión de semillas de A. cruentus en 15% de la ración disminuyó el colesterol en la yema de huevos, sin afectar significativamente los principales parámetros productivos.
       
  • INTERNATIONAL PRICE TRASMISSION IN THE CHILEAN DAIRY MARKET

    • Abstract: RESUMEN En una economía abierta, como la de Chile, los precios internacionales influyen sobre los precios domésticos. Esta relación puede dar indicios de distorsión en el mercado cuando la transmisión de precios no es instantánea. En este caso, resulta relevante estudiar esta relación en el mercado lácteo chileno con la finalidad de adoptar políticas de corrección de las fallas de mercado. El objetivo de esta investigación fue determinar la medida en que se relacionan los precios de exportación e importación de lácteos con el precio pagado a productores lecheros en Chile, entre los años 1990-2018. La metodología utilizada fue el análisis de cointegración y Modelo de Corrección de Errores (ECM). Mediante la aplicación del test de cointegración se obtiene que el precio nacional presenta una relación de equilibrio de largo plazo con el precio de exportación, no así con el precio de importación. Los resultados de la estimación del ECM entre precio nacional y precio de exportación indican que tanto los coeficientes de ajuste de corto plazo como de largo plazo son estadísticamente significativos, hecho que evidencia que la referencia para la fijación de precios por parte de la industria en Chile es el precio de exportación. La magnitud de estos parámetros revela que las variaciones del precio de exportación no se transmiten instantáneamente hacia el precio nacional.ABSTRACT In an open economy like Chile, international prices influence domestic prices. This relationship can result in market distortions when price transmission is not instantaneous. In this sense, it becomes relevant to study this relationship in the Chilean dairy market to adopt policies to correct market failures. The objective of this research was to determine the extent to which export and import prices of dairy products are related to the price paid to dairy producers in Chile between the years 1990-2018. The methodology used was cointegration analysis and Error Correction Model (ECM). By applying the cointegration test, it was observed that that there is a long-term equilibrium relationship between local and export prices, but not with import price. The results of the ECM estimation between local and export prices indicate that both short-term and long-term adjustment coefficients are statistically significant. This indicates that the reference for industry pricing in Chile is export price. The magnitude of these parameters reveals that the variations in export price are not transmitted instantaneously to local price.
       
 
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