Efecto de la infestación de Micrapate scabrata (Erichson, 1847) (Coleoptera: Bostrichidae) en la degradación de madera y sus consecuencias en algunas propiedades químicas del suelo

Micrapate scabrata (Erichson) (Coleoptera: Bostrichidae) is a xylophagous beetle native to Chile. Adults and larvae feed on several native host plants, but also on pruned wood of exotic plants. In this study we assessed the impact of artifi cial M. scabrata infestation on Vitis vinifera L. wood degradation and the subsequent changes in soil properties. First, we periodically sampled, during a four-month period, pruned wood from an infested table grape vineyard, fi nding in average 1 adult/10 cm linear wood. Adults were then placed in large Petri dishes containing uninfested wood samples, and maintained in a climatic chamber for six months. At the end of this period, an average of 65.6% of infested wood had been turned mainly into sawdust. Additionally, the impact of leaving M. scabrata infested pruned wood on potted soil for six months, under laboratory conditions, was also evaluated. Afterwards, the surface soil content of macro elements (N-P-K) and organic matter signifi cantly increased, whereas the soil pH decreased. These results document the signifi cant impact of M. scabrata infestation on pruning wood degradation and the benefi ts to the soil if left on the ground in the ecosystem.Micrapate scabrata (Erichson) (Coleoptera: Bostrichidae) es una especie xilófaga y nativa de Chile. Las larvas y los adultos se alimentan de madera de varias especies nativas, y también de madera de poda de plantas exóticas. En este estudio evaluamos el impacto de una infestación artifi cial de M. scabrata en la degradación de madera de Vitis vinifera L. y los cambios subsecuentes en las propiedades del suelo. Para ello, primero muestreamos madera de poda, durante cuatro meses, en un parronal de uva de mesa infestado, y encontramos en promedio 1 adulto/10 cm lineales de madera. Luego se infestó madera de poda sana, dispuesta en placas de Petri, con adultos, las que se mantuvieron en una cámara climática por seis meses. En ese plazo, un 65.6% de la madera infestada fue convertida principalmente en aserrín. Adicionalmente, se evaluó el efecto de dejar madera de poda infestada por M. scabrata en macetas con suelo, durante seis meses, en condiciones de laboratorio. Luego de ese período, se encontró que el contenido de macro-elementos (N-P-K) y materia orgánica en el suelo aumentó signifi cativamente, mientras que el pH disminuyó. Estos resultados muestran el impacto signifi cativo de la infestación de madera por M. scabrata en su degradación y los benefi cios para la condición del suelo si es dejado en superfi cie en el ecosistema

Aislamiento y caracterización de bacterias endosimbióticas procedentes de suelos contaminados por cobre en Chile

El uso intensivo de compuestos de cobre como herbicidas y fungicidas provoca la contaminación de suelos de uso agrícola debido a la acumulación de este metal en las capas más superficiales del suelo. Se sabe que la presencia de cobre y otros metales pesados afecta negativamente a las interacciones simbióticas que se establecen entre bacterias diazotróficas de los géneros Rhizobium, Sinorhizobium y Bradyrhizobium y leguminosas de interés agrícola (Laguerre et al., 2006). El objetivo de este trabajo es estudiar la diversidad de cepas endosimbióticas de leguminosas en suelos agrícolas chilenos que presentan un elevado contenido en cobre como resultado de la contaminación con residuos de extracciones mineras. Además, se pretende caracterizar el nivel de resistencia a cobre en las cepas aisladas con objeto de identificar aquellas altamente eficientes que puedan ser utilizadas como inoculantes microbianos. Para ello, se han prospectado 9 suelos agrícolas de las regiones III, V y VI de Chile con contenidos muy variables de metales. Utilizando estos suelos como inóculos de plantas trampa de leguminosas se ha obtenido una colección de 362 cepas aisladas de nódulos de guisante (Pisum sativum), judía (Phaseolus vulgaris) y alfalfa (Medicago sativa). Los análisis filogenéticos y los ensayos de resistencia a cobre realizados han permitido caracterizar y seleccionar aquellas cepas con mayores niveles de resistencia a este metal. Los resultados demuestran que los suelos altamente contaminados por cobre poseen una menor diversidad de bacterias endosimbióticas; las cepas más resistentes han sido aisladas de los suelos con niveles de contaminación intermedia. Los análisis fenotípicos y moleculares realizados sobre las cepas más resistentes han demostrado la existencia de sistemas de resistencia a cobre inducibles por este metal y potencialmente implicados en su homeostasis

Evaluation for fresh consumption of new broad bean genotypes with a determinate growth habit in central Chile

Broad bean (Vicia faba L. [unranked] major (Harz) Beck) is usually consumed dry. In Chile, however, broad bean is grown as a vegetable crop with indeterminate genotypes. The new 'Alarga', 'Retaca' and 'Verde Bonita' broad bean genotypes, which have a determinate growth habit, were evaluated in six irrigated environments in central Chile at three locations (Rancagua, Talca, and Talagante) and on two planting dates (F1 and F2; 1-mo apart). The aim was to characterize their yield and select the best-yielding genotypes in terms of pod yield (PY) and fresh grain yield (GY). The best location(s) to produce fresh pods and fresh grain were also identified and described. Fresh grain yield and components were measured and the genotype x environment interaction (GxE) was analyzed. Pod yield differed among genotypes; 'Verde Bonita' and 'Retaca' had the highest PY (15 500 kg ha-1, 8% higher than 'Alarga'). There was a GxE interaction for GY and 'Retaca' had its highest yield in Talca on the two planting dates and in Rancagua when planted late (F2). Mean GY of 'Retaca' was 3900 kg ha-1 with the highest number of grains per 1 m² (NG). The best GY was related to a higher seasonal photothermal quotient (ranging from 1.15 to 1.82 MJ m-2 d-1 °C-1, r = 0.90, P d" 0.001). The lowest GY was in Talagante on F1. Genotypes differed in yield composition; 'Retaca' had many small pods giving many seeds per unit area and 'Verde Bonita' had large pods yielding fewer grains per unit area. The 'Retaca' genotype is preferred by the frozen broad bean industry, whereas 'Verde Bonita' is preferred by the fresh broad bean market

Evaluation for fresh consumption of new broad bean genotypes with a determinate growth habit in central Chile

Broad bean ( Vicia faba L. [unranked] major (Harz) Beck) is usually consumed dry. In Chile, however, broad bean is grown as a vegetable crop with indeterminate genotypes. The new 'Alarga', 'Retaca' and 'Verde Bonita' broad bean genotypes, which have a determinate growth habit, were evaluated in six irrigated environments in central Chile at three locations (Rancagua, Talca, and Talagante) and on two planting dates (F1 and F2; 1-mo apart). The aim was to characterize their yield and select the best-yielding genotypes in terms of pod yield (PY) and fresh grain yield (GY). The best location(s) to produce fresh pods and fresh grain were also identified and described. Fresh grain yield and components were measured and the genotype x environment interaction (GxE) was analyzed. Pod yield differed among genotypes; 'Verde Bonita' and 'Retaca' had the highest PY (15 500 kg ha-1, 8% higher than 'Alarga'). There was a GxE interaction for GY and 'Retaca' had its highest yield in Talca on the two planting dates and in Rancagua when planted late (F2). Mean GY of 'Retaca' was 3900 kg ha-1 with the highest number of grains per 1 m2 (NG). The best GY was related to a higher seasonal photothermal quotient (ranging from 1.15 to 1.82 MJ m-2 d-1 °C-1, r = 0.90, P ≤ 0.001). The lowest GY was in Talagante on F1. Genotypes differed in yield composition; 'Retaca' had many small pods giving many seeds per unit area and 'Verde Bonita' had large pods yielding fewer grains per unit area. The 'Retaca' genotype is preferred by the frozen broad bean industry, whereas 'Verde Bonita' is preferred by the fresh broad bean market

Climatic zoning of chia (Salvia hispanica L.) in Chile using a species distribution model

Salvia hispanica L., known as chia, is a plant species originally from tropical and subtropical Mesoamerica. It is economically important because its seeds produce omega-3, thus its demand has increased in Chile and internationally. As there is no commercial production in Chile, we investigated the places in the country where this species could be cultivated in order to satisfy at the least the national demand. The aim of the study was to quantify the main climatic requirements of chia and to produce a climatic aptitude map for chia cultivation in Chile. The methodology was based on the Maxent species distribution model. We used 78 georeferenced data points where chia is grown throughout the world, mostly from the GBIF database, along with raster climatic layers from the Worldclim project. We estimated the performance curves of annual precipitation and temperature along with their respective optimal and critical values, in analogy with the Ecocrop method. The maps used two scenarios for crops in different conditions, with and without irrigation. The results indicated that the intermediate depression and coastal edge of mainly the Arica y Parinacota, Tarapacá, Antofagasta and Atacama regions have optimum conditions for irrigated crops, but it would be impossible in rainfed conditions. We conclude that chia’s cultivation niche is reduced due to its tropical climate requirements; however, it can be cultivated under irrigation in northern Chile

Climatic zoning of chia (Salvia hispanica L.) in Chile using a species distribution model

Salvia hispanica L., known as chia, is a plant species originally from tropical and subtropical Mesoamerica. It is economically important because its seeds produce omega-3, thus its demand has increased in Chile and internationally. As there is no commercial production in Chile, we investigated the places in the country where this species could be cultivated in order to satisfy at the least the national demand. The aim of the study was to quantify the main climatic requirements of chia and to produce a climatic aptitude map for chia cultivation in Chile. The methodology was based on the Maxent species distribution model. We used 78 georeferenced data points where chia is grown throughout the world, mostly from the GBIF database, along with raster climatic layers from the Worldclim project. We estimated the performance curves of annual precipitation and temperature along with their respective optimal and critical values, in analogy with the Ecocrop method. The maps used two scenarios for crops in different conditions, with and without irrigation. The results indicated that the intermediate depression and coastal edge of mainly the Arica y Parinacota, Tarapaca, Antofagasta and Atacama regions have optimum conditions for irrigated crops, but it would be impossible in rainfed conditions. We conclude that chia's cultivation niche is reduced due to its tropical climate requirements; however, it can be cultivated under irrigation in northern Chile.National Fund for Scientific and Technological Development (FONDECYT), Chile 112020

Paraheliotropism can protect water-stressed bean (Phaseolus vulgaris L.) plants against photoinhibition

In order to estimate the importance of leaf movements on photosynthesis in well-watered and water-stressed field grown bean cultivars (Arroz Tuscola (AT), Orfeo INIA (OI), Bayos Titan (BT), and Hallados Dorado (HD)), CO2 assimilation, leaf temperature, and capacity for the maximum quantum yield recovery, measured as Fv/Fm, were assessed. Leaf water potential was lower in water-stressed compared to control plants throughout the day. Water status determined a decrease in the CO2 assimilation and stomatal conductance as light intensity and temperature increased up to maximal intensities at midday. Both parameters were lower in stressed compared to control plants. Even though high light intensity and water-stress induced stomatal closure is regarded as a photoinhibitory condition, the recovery of variable to maximal fluorescence (Fv/Fm) after 30 min of darkness was nearly constant in both water regimes. In fact, higher values were observed in OI and AT when under stress. Photochemical an