Revista de la Facultad de Ciencias Agrarias
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Salicylic acid and Bacillus subtilis as control of early blight (Alternaria solani) in tomato plants (Solanum lycopersicum)
Get PDFAlternaria solani is the causal agent of early blight disease in tomatoes (Solanum lycopersicum) and every year is responsible for significant economic losses suffered worldwide by the producers of this crop. Since salicylic acid and Bacillus subtilis are resistance-inducing agents in plants, they were evaluated in order to know their effect on the infection caused by early blight in the tomato crop. Plants of 75 days old were transplanted in furrows 8 m wide by 43.2 m long, the exogenous application of treatments were made, growth variables (plant height and stem diameter), yield (total fruits) and damage in tomato plants were evaluated. The results show significant statistical differences between treatments compared with the control (P≤0.000). B. subtilis applied to the root and salicylic acid applied to the foliage, reduced the severity of A. solani in tomato plants, and caused a significant increment in the crop growth and yield. The use of resistance inducers can represent an alternative of sustainable production and efficient control against pathogens, aimed at reducing the use of agrochemicals and production costs.Alternaria solani is the causal agent of early blight disease in tomatoes (Solanum lycopersicum) and every year is responsible for significant economic losses suffered worldwide by the producers of this crop. Since salicylic acid and Bacillus subtilis are resistance-inducing agents in plants, they were evaluated in order to know their effect on the infection caused by early blight in the tomato crop. Plants of 75 days old were transplanted in furrows 8 m wide by 43.2 m long, the exogenous application of treatments were made, growth variables (plant height and stem diameter), yield (total fruits) and damage in tomato plants were evaluated. The results show significant statistical differences between treatments compared with the control (P≤0.000). B. subtilis applied to the root and salicylic acid applied to the foliage, reduced the severity of A. solani in tomato plants, and caused a significant increment in the crop growth and yield. The use of resistance inducers can represent an alternative of sustainable production and efficient control against pathogens, aimed at reducing the use of agrochemicals and production costs
Maíces locales; una contextualización de identidad tradicional
Get PDFThis article rises at a first glance on the how important is to agree on an integrative concept for the diversity richness of the maize species and currently grown and preserved in different agroecological and cultural contexts of Mexico, and arises as a conceptual necessity for research project about maize and its multiple purpose uses. The article is proposed due to the current confusion between some concepts and definitions usually read and heard in academic vocabulary regarding the maize. This proposal is made from a literature review of academic documents; with an ethnoagronomic and holistic approach of conceptual integration on the use, management and conservation of maize. Classic and recent academic information was used to decipher and point out the trends in the nomenclature (concepts and definitions) used to name the types of maize currently grown. In conclusion, it is proposed that the maize grown mainly in rural communities could be called "local maize", especially those that are used from the integration of cultural, genetic and phenotypic components or that originate as a result of continuous use, management and conservation in those niches where they can be found.En este artículo se plantea la importancia de acordar un concepto integrador para referirse a los maíces cultivados y conservados en diferentes contextos agroecológicos y culturales, y surge como una necesidad conceptual de un proyecto de investigación sobre maíces y sus usos múltiples. Es decir, el artículo se propone debido a la confusión actual que existe entre algunos conceptos y definiciones que normalmente se leen y escuchan en el lenguaje académico respecto del maíz. Esta propuesta se hace a partir de una revisión de documentos académicos; con un enfoque etnoagronómico y holístico de integración conceptual en el uso, manejo y conservación de los maíces. Se recurrió a información académica clásica y reciente para descifrar y puntualizar las tendencias en la nomenclatura (conceptos y definiciones) que se le asigna a los tipos de maíces cultivados. A manera de conclusión se plantea que los maíces que han sido seleccionados y conservados por los propios productores, se les llame "maíces locales"; principalmente aquellos que se utilizan desde la integración de los componentes culturales, genéticos y fenotípicos, y que se originan como resultado de un uso, manejo y conservación continuos en aquellos nichos donde se encuentran presentes
The edaphic macrofauna in three components of the coffee plant arrangement associated with different management typologies, Antioquia, Colombia
Get PDFThe balance and sustainability of coffee agroecosystems in southwestern Antioquia depend on the interactions and synergisms that take place above and below the ground. Within these, the functional groups of edaphic macrofauna constitute bio-indicators of soil quality. The present research on coffee systems evaluates the edaphic macrofauna in three components of the plant arrangement, under different management typologies. The study was carried out in the San Gregorio, La Soledad, La Clara and Egypt townships of Santa Rita in the municipality of Andes, Antioquia. The assessment of the edaphic macrofauna was carried out by random stratified sampling under coffee canopy, under banana canopy and in the furrow, in three zones of the slope of each productive system. A general linear model, multivariate techniques of Manovas and Biplot were used as statistical methods. The greatest interaction of the macrofauna groups was presented in the order of the systems: Transition II (Use of organic inputs)>Transition I (Rationalization of synthetic inputs)>Conventional (Use of chemical inputs), and by plant arrangement components in the order Banana>Coffee>Furrow.The balance and sustainability of coffee agroecosystems in southwestern Antioquia depend on the interactions and synergisms that take place above and below the ground. Within these, the functional groups of edaphic macrofauna constitute bio-indicators of soil quality. The present research on coffee systems evaluates the edaphic macrofauna in three components of the plant arrangement, under different management typologies. The study was carried out in the San Gregorio, La Soledad, La Clara and Egypt townships of Santa Rita in the municipality of Andes, Antioquia. The assessment of the edaphic macrofauna was carried out by random stratified sampling under coffee canopy, under banana canopy and in the furrow, in three zones of the slope of each productive system. A general linear model, multivariate techniques of Manovas and Biplot were used as statistical methods. The greatest interaction of the macrofauna groups was presented in the order of the systems: Transition II (Use of organic inputs)>Transition I (Rationalization of synthetic inputs)>Conventional (Use of chemical inputs), and by plant arrangement components in the order Banana>Coffee>Furrow
The gender role on moderator effect of food safety label between perceived quality and risk on fresh vegetables
Get PDFThe role of food safety label in fresh vegetables has received little attention in developing economies and less attention from the perspective of gender. In this context, a conceptual model was developed to explain the effect of food safety label as a moderator variable of risk perception and quality perceived for fresh vegetables from the perspective of gender. A structural equation model was developed in central and south central Chile, using a convenience sample (n = 1114) of vegetables buyers. The main finding of the study was that for females, the food safety label moderated the effect of risk perception on perceived quality; while for males this effect was not significant. However, given that females are primarily responsible for purchasing food, food safety labels are a tool for consumers to recognize unsafe vegetables; at the same time, it can influence the purchase decision of those consumers worried by certain risks associated with fresh vegetables.The role of food safety label in fresh vegetables has received little attention in developing economies and less attention from the perspective of gender. In this context, a conceptual model was developed to explain the effect of food safety label as a moderator variable of risk perception and quality perceived for fresh vegetables from the perspective of gender. A structural equation model was developed in central and south central Chile, using a convenience sample (n = 1114) of vegetables buyers. The main finding of the study was that for females, the food safety label moderated the effect of risk perception on perceived quality; while for males this effect was not significant. However, given that females are primarily responsible for purchasing food, food safety labels are a tool for consumers to recognize unsafe vegetables; at the same time, it can influence the purchase decision of those consumers worried by certain risks associated with fresh vegetables
Finite (Hausdorff) dimension of plants and roots as indicator of ontogeny
Get PDFThe architecture of plants responds to endogenous processes and to the influence of environmental factors. The allometric study of architecture has been a challenge for biology. We define a new finite (Hausdorff) dimension of plants, that considers both the aerial part and the roots, and compute examples. This new finite dimension was introduced recently and, in contrast to the classical Hausdorff dimension, is not zero on finite sets. We propose the finite dimension, as a function of time, as a "signature" of the plant or root. Our first results suggest that the signature is specific to each plant species and its growth period, and constitutes an objective metric that allows to study its ontogenesis in detail.The architecture of plants responds to endogenous processes and to the influence of environmental factors. The allometric study of architecture has been a challenge for biology. We define a new finite (Hausdorff) dimension of plants, that considers both the aerial part and the roots, and compute examples. This new finite dimension was introduced recently and, in contrast to the classical Hausdorff dimension, is not zero on finite sets. We propose the finite dimension, as a function of time, as a "signature" of the plant or root. Our first results suggest that the signature is specific to each plant species and its growth period, and constitutes an objective metric that allows to study its ontogenesis in detail
Fibrolytic activity of four Trichoderma strains grown on agro-industrial residues
Get PDFThe aim of this study was to compare the cellulolytic and xylanolytic activities of two strains of Trichoderma viride, one of Trichoderma reesei and one of Trichoderma harzianum grown on four different substrates. Each substrate contained 20% wheat bran and 80% agro-industrial waste (corn stover (CS), sugarcane bagasse (SCB), Yucca schidigera fiber (YS), or compost elaborated from solid waste generated in the university cafeteria (CSW)). An interaction (P < 0.01) between the substrate and strain was detected for both cellulolytic and xylanolytic enzyme activities. The highest cellulolytic activity (P < 0.01) was obtained with T. reesei grown on YS, CS, and SBC, and the lowest was from the two T. viride strains grown on most of the substrates. The highest xylanolytic activities (P < 0.01) were detected for T. harzianum with YS and SCB and T. reesei with CSW and CS, while one T. viride strain exhibited intermediate and the other showed the lowest activity. In conclusion, T. reesei CDBB356 showed the highest fibrolytic activity for most of the tested substrates, a finding that suggests it has the highest potential for fibrolytic enzyme production. There is a potential application for T. reesei CDBB356 enzymes on ruminant feed supplements to improve forage digestibility.The aim of this study was to compare the cellulolytic and xylanolytic activities of two strains of Trichoderma viride, one of Trichoderma reesei and one of Trichoderma harzianum grown on four different substrates. Each substrate contained 20% wheat bran and 80% agro-industrial waste (corn stover (CS), sugarcane bagasse (SCB), Yucca schidigera fiber (YS), or compost elaborated from solid waste generated in the university cafeteria (CSW)). An interaction (P < 0.01) between the substrate and strain was detected for both cellulolytic and xylanolytic enzyme activities. The highest cellulolytic activity (P < 0.01) was obtained with T. reesei grown on YS, CS, and SBC, and the lowest was from the two T. viride strains grown on most of the substrates. The highest xylanolytic activities (P < 0.01) were detected for T. harzianum with YS and SCB and T. reesei with CSW and CS, while one T. viride strain exhibited intermediate and the other showed the lowest activity. In conclusion, T. reesei CDBB356 showed the highest fibrolytic activity for most of the tested substrates, a finding that suggests it has the highest potential for fibrolytic enzyme production. There is a potential application for T. reesei CDBB356 enzymes on ruminant feed supplements to improve forage digestibility
Morphological variability of native maize (Zea mays L.) of the west highland of Puebla and east highland of Tlaxcala, Mexico
Get PDFThe objective of this research was to assess the morphological variability of maize landraces native of the west highland of Puebla and east highland of Tlaxcala, México, in order to, besides define it, related it to races, commercial varieties and with the altitude of the localities of seed collection. The genetic resources evaluated were 134 accessions collected in 34 localities, along with 10 controls. Experiments were established on three localities using a Lattice 12 x 12. Thirty-two morphological traits were analyzed, 27 of them resulting with highly significant differences, reflecting the high variability at the level of morphological characters, many of them of agronomic interest. From variance analysis 16 traits were selected for use in a cluster analysis through the Modified Localization Method, which joint the populations in six groups, most of them in the group 1, with morphological traits of long cycle varieties: high plants, with greater primary branches of the tassel, greater ear diameter and length, and greater grain length and width. The conclusions indicate that the morphological variability of Landraces is not associated with the altitude of localities of seed collection and that these have more relation with Chalqueño race, small with Conico race, absent with Conico Norteño and Palomero Toluqueño races and almost absent with commercial varieties.The objective of this research was to assess the morphological variability of maize landraces native of the west highland of Puebla and east highland of Tlaxcala, México, in order to, besides define it, related it to races, commercial varieties and with the altitude of the localities of seed collection. The genetic resources evaluated were 134 accessions collected in 34 localities, along with 10 controls. Experiments were established on three localities using a Lattice 12 x 12. Thirty-two morphological traits were analyzed, 27 of them resulting with highly significant differences, reflecting the high variability at the level of morphological characters, many of them of agronomic interest. From variance analysis 16 traits were selected for use in a cluster analysis through the Modified Localization Method, which joint the populations in six groups, most of them in the group 1, with morphological traits of long cycle varieties: high plants, with greater primary branches of the tassel, greater ear diameter and length, and greater grain length and width. The conclusions indicate that the morphological variability of Landraces is not associated with the altitude of localities of seed collection and that these have more relation with Chalqueño race, small with Conico race, absent with Conico Norteño and Palomero Toluqueño races and almost absent with commercial varieties
Dispersal of the pea leaf miner Liriomyza huidobrensis (Blanchard, 1926) (Diptera: Agromyzidae): a field experiment
Get PDFMovement of herbivore insects within agroecosystems can ultimately determine the level of damage to crops. It was evaluated the dispersal of Liriomyza huidobrensis (Blanchard, 1926) (Diptera: Agromyzidae) under field conditions. In addition, it was evaluated if body size was related to dispersal distance. Eight hundred individuals of L. huidobrensis were released in the central point of a series of concentric circles (6, 12, 24, 48, and 96 m in radius), where 117 yellow sticky traps were set to insect recapture. Circular Statistics were used to evaluate flight direction whereas hurdle models were applied to analyze dispersal probability in relation to distance. Five percent of the released individuals were recaptured, being 36 m the median distance of recapture. The distribution of recaptured insects was not random around the circles, but the preferential dispersal direction was not explained by wind direction. The incidence of recaptured L. huidobrensis of both sexes significantly decreased at increasing distances from the release point, but decayed faster for females. No effect was found of body size on the distance of recapture. The results suggest that L. huidobrensis dispersed mainly over short distances with males being capable of performing longer flights than females.Movement of herbivore insects within agroecosystems can ultimately determine the level of damage to crops. It was evaluated the dispersal of Liriomyza huidobrensis (Blanchard, 1926) (Diptera: Agromyzidae) under field conditions. In addition, it was evaluated if body size was related to dispersal distance. Eight hundred individuals of L. huidobrensis were released in the central point of a series of concentric circles (6, 12, 24, 48, and 96 m in radius), where 117 yellow sticky traps were set to insect recapture. Circular Statistics were used to evaluate flight direction whereas hurdle models were applied to analyze dispersal probability in relation to distance. Five percent of the released individuals were recaptured, being 36 m the median distance of recapture. The distribution of recaptured insects was not random around the circles, but the preferential dispersal direction was not explained by wind direction. The incidence of recaptured L. huidobrensis of both sexes significantly decreased at increasing distances from the release point, but decayed faster for females. No effect was found of body size on the distance of recapture. The results suggest that L. huidobrensis dispersed mainly over short distances with males being capable of performing longer flights than females
Evaluación de la transición agroecológica de un establecimiento ganadero a base de pastizal de la cuenca del Salado, mediante indicadores
Get PDFThere are very few documented experiences of agroecological management in extensive systems of temperate zones, particularly those that utilize native grasslands. Therefore, we evaluate the feasibility of the transition from conventional to agroecological management of a farm operation based in the utilization of native grasslands, selecting and validating indicators to evaluate the trajectory of this transition. We used indicators easy to calculate, which showed sensitivity to the production changes. The results obtained in the third year of the agroecological reconversion showed that most of the indicators of the productive dimension (productivity of the natural grassland, forage species cover, state of the breeding herd), environmental dimension (land cover, species richness, decomposition rate of feces) and economic efficiency dimension (gross margin) substantially improved during the reconversion process. This result shows that there is not always a compromise between the preservation of natural capital and the economic benefits. The critical point to ensure the sustainability of these agroecosystems corresponds to the social dimension (land tenure, and the settling down and social relationships of the farmer).Son muy escasas las experiencias documentadas de manejos agroecológicos en sistemas extensivos de zonas templadas, en particular las que contemplen la utilización de pastizales naturales. Por ello nos propusimos evaluar la factibilidad de la transición de un campo de producción convencional a un campo agroecológico a base de pastizal natural, seleccionando y validando indicadores para evaluar la trayectoria de esta transición. Los indicadores utilizados fueron fáciles de calcular y la mayoría mostró sensibilidad a los cambios realizados en el planteo productivo. Los resultados obtenidos al tercer año de la reconversión agroecológica indican que la mayoría de los indicadores de sustentabilidad de las dimensiones productiva (productividad del pastizal natural, cobertura de especies forrajeras, estado corporal del rodeo de cría), ambiental (cobertura del suelo, riqueza de especies, tasa de descomposición de heces) y de eficiencia económica (margen bruto ganadero) mejoraron sustancialmente en el proceso de reconversión, poniendo en evidencia que no siempre existe un compromiso entre el cuidado del capital natural y los beneficios económicos. El punto crítico para garantizar la sustentabilidad de estos agroecosistemas corresponde a la dimensión social (tenencia de la tierra, grado de arraigo del productor y sus vínculos sociales)
Single- and multiple-trait BLUP in genetic selection of parents and hybrids of grain sorghum
Get PDFTo increase yield, breeding programs must search for innovative and efficient methodologies for the development and selection of superior genotypes. Therefore, this study aimed to compare the single- and multiple-trait best linear unbiased prediction (BLUP) in genetic selection of parents and hybrids of grain sorghum. For this, an experiment conducted in alpha-lattice design with two replications was used. Flowering time (FT), plant height (PH), and grain yield (GY) were evaluated in 502 grain sorghum hybrids obtained by the cross of ten restorer lines and 54 male-sterile lines. Variance components were estimated via restricted maximum likelihood (REML). Significant effects of restorer lines, of male-sterile lines, and of specific combining ability were detected by the likelihood ratio test (LRT). The estimates of variance components, genetic parameters, and correlations were similar when obtained via single- and multiple trait- BLUP. Considering hybrids, the multiple-trait BLUP resulted in slightly higher predicted selection gain for the three evaluated traits and, therefore, can be efficiently applied in the genetic selection of grain sorghum.To increase yield, breeding programs must search for innovative and efficient methodologies for the development and selection of superior genotypes. Therefore, this study aimed to compare the single- and multiple-trait best linear unbiased prediction (BLUP) in genetic selection of parents and hybrids of grain sorghum. For this, an experiment conducted in alpha-lattice design with two replications was used. Flowering time (FT), plant height (PH), and grain yield (GY) were evaluated in 502 grain sorghum hybrids obtained by the cross of ten restorer lines and 54 male-sterile lines. Variance components were estimated via restricted maximum likelihood (REML). Significant effects of restorer lines, of male-sterile lines, and of specific combining ability were detected by the likelihood ratio test (LRT). The estimates of variance components, genetic parameters, and correlations were similar when obtained via single- and multiple trait- BLUP. Considering hybrids, the multiple-trait BLUP resulted in slightly higher predicted selection gain for the three evaluated traits and, therefore, can be efficiently applied in the genetic selection of grain sorghum