Showing papers in "Chilean Journal of Agricultural Research in 2009"

Environmental effects of irrigation in arid and semi-arid regions

Abstract: En este trabajo se presenta una revision del estado del arte relativo a los efectos ambientales de la agricultura bajo riego en la calidad del agua y de los suelos en regiones semiaridas y aridas de America Latina a escala de campo. La informacion relevada es escasa y fragmentaria. Ejemplos en areas seleccionadas de otras regiones del mundo muestran claramente la importancia del estudio del impacto ambiental de las practicas de riego en la calidad de agua y del suelo. La mayor parte de los estudios se refieren a anegamiento y salinizacion de suelos. En relacion a los agroquimicos, los fertilizantes han recibido mayor atencion, en particular considerando la lixiviacion de nitratos. El impacto de los microcontaminantes, como los pesticidas o los metales pesados, se ha estudiado mayormente a traves de la aplicacion de modelos. Los compuestos farmaceuticos surgen como contaminantes cuando las aguas servidas se usan para riego sin tratamiento previo, y han comenzado a ser objeto de estudio. Es evidente la necesidad de profundizar los conocimientos en relacion a las tecnologias apropiadas de uso, tratamiento y reutilizacion de aguas servidas, pues constituyen un valioso recurso en regiones semiaridas y aridas.

Biological Activity of Essential Oils from Leaves and Fruits of Pepper Tree (Schinus molle L.) to Control Rice Weevil (Sitophilus oryzae L.)

Abstract: Fil: Benzi, Veronica Soledad. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Bahia Blanca; Argentina. Universidad Nacional del Sur. Departamento de Biologia, Bioquimica y Farmacia; Argentina

Fungistatic Activity Of Essential Oils Extracted from Peumus boldus Mol., Laureliopsis philippiana (Looser) Schodde and Laurelia sempervirens (Ruiz & Pav.) Tul. (Chilean Monimiaceae)

Abstract: Components of essential oils from the Chilean Monimiaceae, boldo (Peumus boldus Mol.), tepa (Laureliopsis philippiana (Looser) Schodde), and laurel (Laurelia sempervirens (Ruiz & Pav.) Tul.) were determined using Gas Chromatography- Mass Spectrometry (GCMS) and fungistatic activity of the essential oils was tested against Rhizoctonia solani Kuhn (Donk), Pythium irregulare Buisman, Ceratocystis pilifera (Fr.) C. Moreau, Phragmidium violaceum (Schultz) G. Winter, and Fusarium oxysporum Schltdl. The essential oils of the Monimiaceae species shared some common components; all three had the 3-carene, α-phellandrene, and α-pinene terpenes. L. philippiana and L. sempervirens also had safrole.The main components were ascaridol in P. boldus oil, 3-carene in L. philippiana, and safrole in L. sempervirens. The essential oil from L. sempervirens showed the highest fungistatic activity with significant differences in dose as well as exposure. P. violaceum was the most sensitive strain and P. irregulare the most resistant of all the essential oils (P. boldus extract affected growth by only 19%). Therefore, essential oils from these three plants could be used to control the fungal strains studied.

Herbage Production, Nutritive Value and Grazing Preference of Diploid and Tetraploid Perennial Ryegrass Cultivars (Lolium perenne L.)

Abstract: The objective of this study was to determine, under the soil and climatic conditions of Southern Chile, the effect of the ploidy of perennial ryegrass (Lolium perenne L.) cultivars on herbage production, nutritive value, grazing preference and utilization of pasture produced. This study was conducted in southern Chile, Valdivia Province, and was evaluated for 3 years. The tetraploid cultivars used were Quartet (4n), Gwendal (4n), Pastoral (4n) and Napoleon (4n). The diploid cultivars were Anita (2n), Jumbo (2n), Aries (2n), and Yatsyn 1 (2n). When the average sward height reached 20 cm, all plots were simultaneously grazed by dairy cows for a period of 24 h. Before and after grazing, sward height, dry matter availability and nutritive value were evaluated. Grazing preference was visually assessed every 5 min for a period of 2.5 h after the afternoon milking. During the 3-year period 20 grazing events were evaluated. A randomized complete block design, with eight cultivars and three replicates, was used. Diploid

Use of Enzymatic Biosensors as Quality Indices: A Synopsis of Present and Future Trends in The Food Industry

Abstract: Biosensors are an important alternative in the food industry to ensure the quality and safety of products and process controls with effective, fast and economical methods. Their technology is based on a specific biological recognition element in combination with a transducer for signal processing. The use of enzymatic biosensor technology in food processing, quality control and on-line processes is promising compared to conventional analytical techniques, as it offers great advantages due to size, cost, specificity, fast response, precision and sensitivity. This article reviews the development and use of some enzyme biosensors in the food industry, describes the most important application areas and analyzes the current situation and future possibilities. In conclusion, enzymatic biosensors are a tool with broad application in the development of quality systems, risk analysis and critical control points, and the extent of their use in the food industry is still largely limited by the short lifetime of biosensors, in response to which the use of thermophilic enzymes has been proposed.

Effect of Compost Application on Some Properties of a Volcanic Soil from Central South Chile

Abstract: Soil compost application is a common soil management practice used by small farmers of Central-South Chile that produces positive effects on soil properties and also promotes presence and activity of arbuscular mycorrhizal fungi (AMF). This fungi form symbiosis with plant roots improving plant nutrition, as well as producing glomalin, a glycoprotein that has been associated with soil aggregation stability. Therefore, the aim of this study was to evaluate, in an Ultisol from Central-South Chile, the effect of different doses of compost on some soil characteristics at the end of the third year of a crop sequence including wheat (Triticum aestivum L.), bean (Phaseolus vulgaris L.), and grassland (Lolium multiflorum Lam. associated with Trifolium repens L.). Studied soil characteristics included chemical (pH, available-P, organic C), biological (C and N biomass, AMF spore number, root colonization percentage, mycelium length, and glomalin content), as well as physical parameters (water holding capacity [WHC], and water stable aggregates [WSA]). Results showed that, in general, compost application increased soil

Kinetic Study of Convective Drying of Blueberry Variety O’neil (Vaccinium corymbosum L.)

Abstract: The aim of this research was to study and to model the drying kinetics of the blueberry (Vaccinium corymbosum L.) at three temperatures (60, 70 and 80 oC) with an airflow of 2.0 ± 0.2 m s -1. Modeling of the desorption isotherm was carried out with the GAB (Guggenheim, Anderson and de Boer) equation, showing a good fit to experimental moisture data, giving as a result a monolayer moisture level of 0.084 g water g-1 dm. Newton, Henderson-Pabis, Page, Modified Page and Logarithmic mathematical models were applied in the study and in the modeling of the drying kinetics of this fruit. Kinetic parameters k of each model showed dependence on temperature, and were evaluated by an Arrhenius-type equation, with an activation energy of between 36.2 and 54.5 kJ mol-1. Logarithmic and Modified Page models gave the best fits for each drying curve, based on the statistical test determination coefficient, sum square error, root mean sum errors and Chi-square. In consequence, both models are excellent tools for estimating the drying time of this product.

Inorganic Nutritional Composition of Common Bean (Phaseolus vulgaris L.) Genotypes Race Chile

Abstract: The current Chilean bean (Phaseolus vulgaris L.) collection is about 1110 accessions. To facilitate the characterization of this germplasm a core collection of 246 accessions was formed. Little information exists about the mineral content and other quality traits for those bean genotypes. This information could be useful to determine their quality and to promote its consumption. The objective of this work was to evaluate the variability for macro and micronutrients of a representative bean sample from a Chilean core collection and to compare them with representatives from other races. The results indicated the presence of a wide variability for some macro and micronutrients, such as N, Fe, and Zn. The protein content varied from 183.5 to 259.7 g kg -1 , Fe from 68.9 to 152.4 mg kg -1 , and Zn from 27.9 to 40.7 mg kg -1 . This situation could allow to select those genotypes with higher elements and to improve the current cultivars. The simple correlation analysis indicated that the N content was positively correlated with protein, P, Cu, Zn, and S content and negatively correlated with B content and the C/N ratio of the seed. The Fe content was positively correlated with Mn and Ca content and Zn content was positively correlated with the N, P, Cu and S content and negatively correlated with the relation C/N ratio of bean seed. There were no significant differences between the Chilean bean genotypes compared to genotypes from other races.

Physical and Chemical Characterization of Melia azedarach L. Fruit and Leaf for Use as Botanical Insecticide

Abstract: A study was undertaken of the physical and chemical characteristics and insecticide properties of melia (Melia azedarach L.) (Meliaceae) fruit and leaves; melia has been introduced in Chile for ornamental purposes. The physical and chemical properties were evaluated in two stages of fruit and leaf maturity, i.e., green /mature, and mature/juvenile, respectively. Laboratory bioassays were carried out on Drosophila melanogaster Meigen (Diptera: Drosophilidae) as an insect model. The diameter of M. azedarach fruit was in the lower limit in relation to other studies. The flour obtained from green fruit had an average dry weight inferior to that of mature fruit. The average dry leaf weights were similar in both juvenile and mature states. The green fruits had 50% initial humidity, similar to juvenile (60%) and mature (57%) leaves, but greater than the mature fruits (44%). The chemical analysis of the fruit maturity stages determined a slight increase in crude fiber content as maturity increased. There was a decrease in the lipid content of leaves close to 60% at maturity. Furthermore, an analysis of polyphenols was made using HPLC-DAD (High Performance Liquid Chromatography-Diode Array Detector), and 14 compounds were identified as causes of the insecticidal effect of the M. azedarach fruit, of which three would correspond to flavonoids: one catechin and two kaempherols. Finally, the aqueous fruit and leaf extracts of M. azedarach were effective insecticides on D. melanogaster, reaching 90% mortality (125 000 mg kg -1 ) with juvenile leaves and 73.3% (10 700 mg kg -1 ) with

Design and Management of Irrigation Systems

Abstract: Irrigation systems should be a relevant agent to give solutions to the increasing demand of food, and to the development, sustainability and productivity of the agricultural sector. The design, managing, and operation of irrigation systems are crucial factors to achieve an efficient use of the water resources and the success in the production of crops and orchards. The aim of this paper is to analyze knowledge and investigations that enable to identify the principal criteria and processes that allow improving the design and managing of the irrigation systems, based on the basic concept that they facilitate to develop agriculture more efficient and sustainable. The design and managing of irrigation systems must have its base in criteria that are relevant, which implies to take into account agronomic, soil, hydraulic, economic, energetic, and environmental factors. The optimal design and managing of irrigation systems at farm level is a factor of the first importance for a rational use of water, economic development of the agriculture and its environmental sustainability.

Influence of Rootstocks on Nitrogen, Phosphorus and Potassium Content in Petioles of Four Table Grape Varieties

Abstract: Four field trials were conducted at Vicuna Experimental Center (30°02’ S, 70°44’ W) located in the Coquimbo Region, Chile, over four seasons, 2002-2003 to 2005-2006, to determine the influence of 10 rootstocks (Freedom, Harmony, Saint George, Salt Creek, SO4, 1613C, 1103P, 99R, 110R, 140Ru, as well as own roots vines) on nutrient content in petioles of vars. Flame Seedless, Thompson Seedless, Superior Seedless and Red Globe grapevines (Vitis vinifera L.). The trials took place at a site that had previously planted to vineyard. The experimental design was a randomized complete block with four replicates. Petioles opposite to clusters were taken at bloom as samples and analyzed for total N, P and K content. Significant differences in nutrient levels due to rootstocks were found in all varieties. Rootstocks increased the levels of petiole nutrients (except P) over the values usually reported in literature for table grapes. Vines grafted onto the rootstock ‘Salt Creek’ had significantly higher petiole N and P content than those on their own roots vines. Total N level increased 67% in ‘Flame Seedless’, 77% in ‘Red Globe’, 33% in ‘Thompson Seedless’ and 8.5% in ‘Superior Seedless’. On the other hand, the petiole P level doubled in all varieties by using ‘Salt Creek’ as rootstock. Potassium status was also affected by rootstocks. ‘Harmony’ and ‘1613C’ showed higher K levels by at least 60% in vars. Flame Seedless, Red Globe and Thompson Seedless as compared to plants grown on their own roots. The present investigation demonstrates that rootstocks may have a considerable effect on grapevine nutrition.

Effect of Arbucula Myrrhizal Fungi on an Ecological Crop of Chili Peppers (Capsicum annuum L.)

Abstract: Mapuche farmers in southern Chile have been cultivating local ecotypes of chili pepper (Capsicum annuum L.), called locally "Cacho de cabra", for many decades. It is used to make "merken", a condiment that is consumed locally and exported. This vegetable requires a nursery stage and can obtain nutritional benefits from symbiotic associations such as mycorrhizal fungi, achieving a better adaptation to transplanting. Arbuscular mycorrhizal fungi (AMF) are obligate biotrophes appearing in abundance in agroecosystems with conservation management. The aim of this study was to compare effectiveness of two AMF, a commercial mycorrhizal inoculant (IC, Glomus intraradices) and another native (IN, Glomus claroideum) with a control without inoculation (-I) on the production and quality of "Cacho de cabra". At 45 days after sowing (DAS) transplanting was carried out and at 90 and 216 DAS fruit quality, fungal and edaphic parameters were evaluated. The harvest was at four stages. With IN inoculation plants and with greater foliar area were obtained. Also, precocity of fruit production was observed. The harvest started 49 days earlier and fresh weight was 177% higher than that of the control. Root colonization was low, showing significant differences between IN and IC, while a large number of spores was produced in the substrate. It was concluded that inoculation with native fungi decreased transplanting stress thus accelerating the maturation stage of plants and resulting in higher and better yield quality.

Irrigation Water Management in Latin America

Abstract: Latin American countries show a great potential for expanding their irrigated areas. Irrigation is important for strengthening local and regional economy and for enhancing food security. The present paper aimed at providing a brief review on key aspects of irrigation management in Latin America. Poor irrigation management can have great impact on crop production and on environment while good management reduces the waste of soil and water and help farmers maximizing their profits. It was found that additional research is needed to allow a better understanding of crop water requirements under Latin American conditions as well as to provide farmers with local derived information for irrigation scheduling. The advantages of deficit irrigation practices and the present and future opportunities with the application of remote sensing tools for water management were also considered. It is clear that due to the importance of irrigated agriculture, collaborative work among Latin American researchers and institutions is of paramount importance to face the challenges imposed by a growing population, environment degradation, and competition in the global market.

Evaluation of top-cross popcorn hybrids using mixed linear model methodology.

Abstract: The market for popcorn (Zea mays L.) has been continuously growing in Brazil fact has required the development of cultivars adapted to local environmental conditions. For this reason, the analytical objectives of this study were to evaluate top-cross popcorn hybrids in relation to popping expansion and grain yield in three different ecogeographic regions of Brazil, in order to estimate variance components using Restricted Maximum Likelihood (REML) and predict breeding values using Best Linear Unbiased Prediction (BLUP). Genetic evaluation considered a linear model with heterogeneous residual (environmental) variances. The Restricted Likelihood Ratio Test (RLRT) evidenced significant differences (p < 0.01) for the genotypic effect. Grain yield showed a moderate heritable trait (h2 = 0.26-0.39). A higher additive genetic control was evidenced for popping expansion (h2 = 0.58-0.85). Genetic correlations and Spearman coefficient between both traits were negative, indicating that selection based on grain yield would have a negative effect on popping expansion. The top-cross hybrids showed an adequate grain yield, whereas the quality of the popcorn was lower than commercial standards.

A study of dairy fafarm technical efficiency using meta-regression: an international perspective.

Abstract: This paper develops a meta-regression analysis to explain the variation of mean technical efficiency (PETP) measurements from a total of 65 frontier studies that report technical efficiency (ET) measurements at the dairy farm level in the literature published in English and Spanish. The analysis includes the effect of methodology on ET measurements, as well as the effect of the econometric procedure on the meta-regression estimates. Eight models were estimated, and two of these were selected: a fixed effects specification with dummy variables for the most significant studies without geographical effects (EFS), and a specification where the multiple observations are averaged and geographical effects included (OP). Based on model performance, the EFS option is chosen for the analysis. The results of the EFS model suggested that non-parametric deterministic models generate higher PETP estimates than the parametric cases (stochastic and deterministic frontier models). In addition, the Cobb-Douglas and translog forms yield higher average PETP than all other functional forms, cross-sectional data produce higher ET estimates than panel data, and the PETP is higher when the study is input-oriented. The primal approach implies a higher ET estimate than the dual analysis, and when more variables are included in the model, the PETP value is higher.

Importance of Ionic and Osmotic Components of Salt Stress on the Germination of Four Quinua (Chenopodium quinoa Willd.) Selections

Abstract: The influence of the components of saline stress (osmotic and ionic factors) were evaluated during the germination of four quinua (Chenopodium quinoa Willd.) selections in Chile, two collected in the arid northern highland region with saline soils (Amarilla and Roja) and the other two from the rainy southern region with non-saline soils (Hueque and Pucura). The seeds were treated with different saline concentrations (0, 0.2, 0.4, 0.8 and 1.2 M NaCl). Germination kinetics shows that the control treatments of the four selections reach 100% germination. With application of 0.4 M NaCl (LD50max) germination was reduced by 53% in the Amarilla selection and 89.9% in Hueque. The germination rate was lower for the seeds from non-saline areas, which reached germination after 22 h, compared to 10 h for Amarilla. By separating the salinity stress factors (osmotic and ionic), it is evident that they have different degrees of influence on quinua germination, according to each selection. Thus, the germination of Amarilla selection from the arid area was the least influenced by the ionic factor (27%), Pucura and Roja were more affected by the ionic factor (40% and 46% respectively), and Hueque, from the rainy area, was more affected by the osmotic factor, in which caused a 50% loss in germination.

Prediction of the Composition of Fresh Pastures by Near Infrared Reflectance or Interactance-Reflectance Spectroscopy

Abstract: Fast and precise analytical tools can contribute to optimize pasture management decisions. This work was carried out to evaluate the potential of one such technique, near infrared spectroscopy (NIRS), to predict the nutritional value of pastures without previous drying of the samples, comparing two forms of collecting the spectra: reflectance, or interactance-reflectance (fiber optic probe). Samples (n = 107) from different swards were taken across the humid and temperate regions (Los Rios and Los Lagos) of southern Chile. Once their spectra were collected, dry matter (DM) and several chemical constituents, such as crude protein (CP), metabolizable energy (ME), neutral (NDF) and acid detergent fiber (ADF), soluble carbohydrates (SC), soluble crude protein (SCP) and neutral detergent insoluble N (NDFIN), were determined as reference data. Calibrations were developed and the best ranked were selected (by cross-validation) according to a lower standard error of cross validation (SECV) and a higher determination coefficient of cross validation (R 2 CV). Calibrations in the reflectance mode, for DM and CP, reached a high R 2 CV (0.99 and 0.91, respectively) and a SECV (6.5 and 18.4 g kg-1). Equations for ADF, SCP and ME were ranked next, with R2 CV of 0.87, 0.84 and 0.82, respectively, and SECV of 15.88 g kg-1, 15.45 g kg-1 and 0.34 Mj kg-1. Equations for NDF, SC and NDFIN, with R2 CV of 0.78, 0.77 and 0.61, respectively, and SECV of 35.57, 94.54 and 1.89 g kg-1, respectively, are considered unreliable for prediction purposes. Interactance-reflectance, on the other hand, resulted in poorer equations for all fractions.

Effect of the Irrigation Canal Network on Surface and Groundwater Interactions in the Lower Valley of the Cachapoal River, Chile

Abstract: Agricultural production of high value crops in Chile's Central Valley is highly dependent on surface and groundwater resources They are connected and together form an integrated hydrological system, the individual components of which have to be studied This research is addressed to answering two questions: 1) to what extent do irrigation and canal seepage contribute to groundwater recharge and 2) what is the influence of the interactions between the Cachapoal River and ground water The study was carried out from 2003 to 2007 in Peumo Valley (343° S, 713° W) In winter, the irrigation canal network intercepts and diverts surface runoff, which flows to flat areas and recharges groundwater In summer, infiltration from the canals recharges the aquifer directly and partially compensates for water uptake from plants and evaporation The effects of both interactions keep groundwater at a relatively constant level over the whole year The water balance of the valley is strongly affected by agricultural practices, groundwater recharge mainly originating from irrigation loss (22%) and canal seepage (52%) It is important to know how management decisions, such as change in irrigation practices or canal lining, can affect the hydrological system and agricultural production within the valley

Effect of Ethylene Inhibitors on Quality Attributes of Apricot cv. Modesto and Patterson during Storage

Abstract: El damasco (Prunus armeniaca L.) es muy susceptible al ablandamiento de la pulpa, perdida de sabor y pudriciones, especialmente durante postcosecha. Muchos de estos cambios que ocurren durante maduracion son regulados por etileno. El objetivo del presente trabajo fue determinar el cambio de la calidad de damascos var. Modesto y Patterson tratados con 1-metilciclopropeno (1-MCP) y aminoetoxivinilglicina (AVG). Las dosis utilizadas fueron de 1000 y 10 000 nL L-1 de 1-MCP (SmartFresh™), 100 y 1000 mg L-1 de AVG (Retain® 15% p/p) y su respectivo testigo. Las evaluaciones se realizaron tras 20 y 30 dias de almacenamiento a 0 oC con su respectiva evaluacion tras 3 a 4 dias a 20 °C. En ambas variedades, los inhibidores de etileno aplicados tienen efecto en disminuir la tasa de produccion de etileno respecto al testigo, especialmente para Patterson. Tambien se observo un efecto en la firmeza y retencion de color de los frutos, presentando los tratamientos con inhibidores de etileno valores superiores respecto al testigo, por lo que estos parametros serian dependientes de la produccion de etileno. Para contenido de solidos solubles y acidez titulable, no se obtuvieron resultados que puedan establecer diferencias entre frutos tratados y no tratados, por lo tanto se consideran etileno independientes. Los volatiles que presentaron una dependencia de la produccion de etileno fueron los pertenecientes a los grupos de esteres y aldehidos, no siendo el caso de los alcoholes y terpenos que no presentaron variaciones, lo que sugiere que el etileno no estaria involucrado en su sintesis.

Mycorrhizal Propagule Persistence in a Succession of Cereals in a Disturbed and Undisturbed Andisol Fertilized with Two Nitrogen Sources

Abstract: Arbuscular mycorrhizal fungi (AMF) form symbiosis with plant roots, improving its establishment, nutrition, and tolerance to adverse soil conditions. In annual crop rotations, some aspects such as the type of N fertilizer and tillage system used can affect the AMF propagule density and its functionality in the following crop. To analyze the effect of the agronomic practices previously mentioned on the persistence and density of AMF propagules, a study in a succession of cereals was carried out. For this, soil previously cropped with wheat (Triticum aestivum L.) and fertilized with urea (NH4 + ) or sodium nitrate (NO3 ) was disturbed in each case by simulating conventional tillage (CT) or maintained without disturbing, simulating no-tillage (NT). It was then cultivated with oat (Avena sativa L.) using the same N sources. Higher densities of AMF active mycelium and colonized root length in the NT soil were observed (76 and 497% higher than in CT soil, respectively, P < 0.001). Moreover, NT + NO3 interaction produced a higher density of AMF spores (75% higher than in the rest of the treatments, P < 0.05), although showing a decrease in comparison with the previous wheat crop. These results suggest that N source and tillage system interact to

Fecal contamination of groundwater in a small rural dryland watershed in Central Chile.

Abstract: Research on microbiological groundwater quality was conducted in Chile in a rural watershed that has almost no other water source. Forty-two wells were randomly selected and levels of indicator bacteria - total coliforms (TC), fecal coliforms (FC), and fecal streptococci (FS) - were repeatedly measured during the four seasons of 2005. The aim of this study was to characterize microbiological groundwater quality, relate indicator levels to certain watershed features and management characteristics which are likely to affect water quality. The dynamics of seasonal temporal contamination was determined with statistical analyses of indicator organism concentrations. Nonparametric tests were used to analyze relationships between bacterial indicators in well water and other variables. TC, FC, and FS were found in all samples indicating the wells had been contaminated with human and animal fecal material. The frequency distribution of microorganisms fitted a logistic distribution. The concentrations appeared to be temporal and levels varied between seasons with higher concentrations in winter. The cause of contamination could be linked to the easy access of domestic animals to the wells and to the permeable well casing material. Local precipitation runoff directly influenced the bacterial concentrations found in the wells.

Feeding dry olive cake modifies subcutaneous fat composition in lambs,noting cake resistance to degradation and peroxidation

Abstract: The purpose of this experiment was to determine the extent to which lamb carcass quality and fat composition could be altered by applying a dry olive cake-based ration instead of a conventional ration or pasture feeding. Three treatments were compared in a completely randomized experiment using 36 single male Suffolk Down lambs with an initial age and live weight of 80 d and 25 kg, respectively. The three treatments were: (a) suckling lambs kept with their mothers on annual Mediterranean grassland (GRAZE); (b) weaned stall-fed lambs on a control ration (CONC); and (c) weaned stall-fed lambs on an olive cake-based ration (CAKE). At the end of the 28-d experimental period, lambs were slaughtered, carcass quality evaluated, and samples of subcutaneous fat analyzed for fatty acids. Treatments did not differ in weight gain or carcass weight and quality, but highly significant differences were found in several fatty acid contents. CAKE animals had reduced palmitic acid as well as increased oleic and stearic acid contents. Atherogenic and thrombogenic indices improved with cake feeding. Principal component and discriminant analyses clearly differentiated treatments suggesting they could be applicable for traceability purposes. A laboratory experiment demonstrated that with or without added vitamin E, the dry olive cake did not alter its lipid properties with increased storage time.

Evaluation of water requirements for a greenhouse tomato crop using the Priestley-Taylor method.

Abstract: ThePriestley-Taylor�(PT)�modelwasevaluatedforestimatingtherealevapotranspiration�(ETreal)�ofadrip-irrigated� greenhousetomato� (Lycopersicon esculentumMill.)� crop.� ThenetradiationincorporatedinthePTmodelwas� estimatedusingmeteorologicalvariables.�Forthisexperiment,�anautomaticweatherstation�(AWS)�wasinstalled� insidethegreenhousetomeasuresolarradiation�(Rgi),�netradiation�(Rn),�airtemperature�(Ta)�andrelativehumidity� (RH).�AnotherAWSwasinstalledoveragrasscovertomeasureatmosphericconditionsoutsidethegreenhouse.�The� experimentwascarriedoutatthePanguilemoexperimentalstation�(�5°2�'�S,�71°40'�W,�110�m.a.s.l.)�fromAugust� toDecember�2000.�ThePTmodelwasevaluatedusingtheETrealobtainedfromthewaterbalance�(WB)�method.� In this case, values of ETreal by PT model were calculated using: a) Rgi and soil heat flux (G) = 0; b) Rgi and G ≠ 0; c) solar radiation measured outside the greenhouse (Rge) and G = 0; and d) Rge and G ≠ 0. For these cases, resultsindicatedthatPTmodelwasabletocomputeETrealwitherrorslessthan�5%.�Also,�Rnwascalculatedwith� arelativeabsoluteerrorandameandeviationlowerthan�6%�and�0.07�mmd -1 ,�respectively,�usingRgiorRge.�Daily� soil heat flux values equal to zero did not affect the calculation of ETreal values. Thus, the PT model evaluated in thisstudycouldbeusedforschedulingirrigationforagreenhousetomatocrop,�usinginternalmeasurementsofair� temperatureandrelativehumidity,�andexternalmeasurementsofsolarradiation.�Inthiscase,�PTmodelpredicted� theETrealwithanerrorof�6.1%.�

Effect of Pheromone Trap Density on Mass Trapping of Male Potato Tuber Moth Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), and Level of Damage on Potato Tubers

Abstract: La polilla de la papa, Phthorimaea operculella (Zeller), es una de las plagas que causan mayor dano a la papa (Solanum tuberosum L.), tanto a los cultivos en campo como a los tuberculos almacenados, especialmente en zonas de climas calidos y secos. Las larvas de este insecto se desarrollan en el follaje y tuberculos de papa causando perdidas directas del producto a comercializar. La utilizacion de feromonas sinteticas, como una herramienta que interfiere con el apareamiento, ha sido ampliamente demostrada en innumerables especies de polillas y otros insectos. Con el fin de evaluar la efectividad de diferentes densidades de trampas de feromona en la captura de machos de P. operculella, para su futura utilizacioncomo tecnica de trampeo masivo y consecuente disminucion de la reproduccion del insecto, se realizo un estudio durante la temporada 2004-2005, en el Valle del Elqui, Region de Coquimbo, Chile. Se evaluaron densidades de 10, 20 y 40 trampas ha-1 con una carga de 0,2 mg de feromona por trampa, utilizando trampas de agua con detergente para las capturas. Los resultados indican que la mayor captura de machos de polilla de la papa se obtiene con densidades de 20 y 40 trampas ha-1, encontrandose tambien una reduccion significativa (P < 0,05) del dano en tuberculos en estos tratamientos comparados con el testigo convencional con aspersiones de insecticidas.

Productivity and Persistence of Yellow Serradela (Ornithopus compressus L.) and Biserrula (Biserrula pelecinus L.) in the Mediterranean Climate Region of Central Chile

Abstract: The production and sustainability of non-irrigated pastures in the Mediterranean climate region of central Chile is currently limited by the low diversity of valuable species and cultivars of annual forage legumes, able to persist in zones with highly variable annual rainfall, and low fertility or poorly drained soils. In this work, DM production, seed yield, hardseededness and pasture persistence were evaluated for cultivars of yellow serradella (Ornithopus compressus L.) and biserrula (Biserrula pelecinusL.),�infieldexperimentsconductedinthesubhumidportion� of the Mediterranean climate region of Chile. Burr medic (Medicago polymorpha L.) and sub clover (Trifolium subterraneum L.) were used as a reference plants. A remarkable DM production and seed yield were observed in biserrula (cvs. Mor96 and Casbah), and in some cultivars of yellow serradella (e.g. Madeira, Santorini); biserrula produced by far the largest number of seeds per m 2 . As was expected for species that produce very high levels of hard-seeds, the regeneration of biserrula and serradella was low in second growing season, but plant density and productivity were high in the third growing season. The use of biserrula and serradela in monoculture or in mixture with other annual legumes, either in pasture-crop rotation or permanent pasture, would contribute to the improvement of the prevailing productive systems in the Mediterranean climate region of central Chile.

SURVIVAL AND REPRODUCTION OF Podisus nigrispinus (HETEROPTERA: PENTATOMIDAE): EFFECTS OF PREY SCARCITY AND PLANT FEEDING

Abstract: The spined soldier bug Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) is a generalist predator that can alternatively feed on plant tissue to survive under prey scarcity. This research aimed to evaluate the effects of plant feeding forced by a shortage of prey on the survival and reproduction of P. nigrispinus on Eucalyptus urophylla S.T. Blake�(Myrtaceae)�plantsinthefield.� Podisus nigrispinus adults were enclosed on branches of eucalyptus by using gauze bags. These adults were fed daily with Tenebrio molitor pupae (T1) or after 5 (T2), 10 (T3) or 15 (T4) days from mating to simulate prey shortage. The pre-oviposition period, number of egg masses, number and viability of eggs and longevity of females were evaluated. Females of P. nigrispinus had a longer pre-oviposition period and produced lower number of egg masses as the period of prey shortage increased. However, the average number of eggs per egg mass, emergence of nymphs and longevity of P. nigrispinus females were not affected by prey shortage. Females of P. nigrispinuscansurvive�15�dayswithoutpreybyfeedingoneucalyptusleavesandifitfindsprey� afterwards can still reproduce. This shows that plant feeding is a successful incidental strategy to survive periods of foodscarcity�(andthusincreasetheefficiency)�ofthispredatorasabiologicalcontrolagent.

Encapsulated Somatic Embryos and Zygotic Embryos for Obtaining Artificial Seeds of Rauli-Beech (Nothofagus alpina (Poepp. & Endl.) Oerst.)

Abstract: Somatic and zygotic embryos from mature seeds of rauli-beech, Nothofagus alpina (Poepp. & Endl.) Oerst., were encapsulated in different artificial endosperms in order to generate a cover that fulfills the function of nourishment and protection of the embryos, facilitating their later germination. The content of sodium alginate varied by 4%, 3%, and 2%, as did the immersion time in calcium chloride (CaCl2), which acts as complexing agent. The artificial endosperm components of the Murashige and Skoog medium (MS) were added, supplemented with 0.5 mg L -1 indolacetic acid (IAA), 0.5 mg L -1 naphthaleneacetic acid (NAA), 2 mg L -1 6-benzylaminopurine (BAP) and 30 g L -1 sucrose. The germinative behaviors of encapsulated somatic and zygotic embryos were evaluated after 4 wk. Comparing the percentages of germination reached by encapsulated somatic and zygotic embryos it was observed that they had similar germinative behavior according to the type of encapsulation applied. However, zygotic embryos substantially exceeded the germination levels reached by somatic embryos, 100% vs. 45% respectively.

Evaluation of a SCAR RYSC3 Marker of the Ry adg Gene to Select Resistant Genotypes to Potato Virus Y (PVY) in the INIA Potato Breeding Program

Abstract: The Potato virus Y (PVY) is distributed worldwide and is one of the most damaging viruses in terms of yield reduction in the potato (Solanum tuberosum L.) crop with losses sometimes reaching 80%. To reduce its impact, there is great interest in obtaining varieties carrying the Ryadg gene that provides extreme resistance to this virus. This couldbefacilitatedwithSCAR�(sequencecharacterizedamplifiedregion)�RYSC3�bymolecularmarker-assisted� selection (MAS). This study compared the effectiveness of the RYSC3 marker in the detection of the Ryadg gene vs. biological tests on populations of the Potato Breeding Program of the Instituto de Investigaciones Agropecuarias (INIA), Chile. Within the group of 71 progenitors, 30 plants had some kind of resistance to the virus, of which 17 were carriers of the RYSC3 marker. These genotypes came from Cornell University, Centro Internacional de la Papa (CIP), Peru, and INIA. The analysis of 460 progenies which came from three different crosses showed that 299 individualsamplifiedtheRYSC3�markerandhadtheresistantphenotype,�withtheexceptionofoneplant.�Within� thegroupofnon-RYSC3�carrierplants,�asignificantpercentage�(22.5%)�showedaresistantphenotype,�indicating� that these progenies segregate other R genes (e.g., hypersensitivity) that reduce biological test effectiveness. This high effectiveness (99.7%) in the detection of the Ryadg gene in both parents and segregating progenies, showed that this marker is appropriate in assisting selection of genotypes with extreme PVY-resistance in the potato breeding programs.

Dissolved Organic Carbon and Nitrogen in Andisol for Six Crop Rotations with Different Soil Management Intensity

Abstract: Soil organic matter (OM) content is a quality indicator, but is an inadequate indicator in the short-term because these changes take place slowly, so dissolved organic components have emerged as an alternative. In volcanic soil subjected to different crop rotations with distinct land use intensity, dissolved organic C and N (DOC and DON) were determined as well as their relationship with total C and N contents in the soil, considering the effects of crop rotation, fertilization level, and soil depth. In humid samples of Humic Haploxerands collected at four depths up to

Life, Seasonal Cycles, and Population Fluctuation of Hippodamia variegata (Goeze) (Coleoptera: Coccinellidae), in the Central Plain of La Araucanía Region, Chile

Abstract: El presente estudio fue llevado a cabo en un cultivo de alfalfa ubicado en el llano central de la Region de La Araucania, Chile, y en el laboratorio de Entomologia Aplicada de la Facultad de Ciencias Agropecuarias y Forestales de la Universidad de La Frontera, donde se determinaron aspectos de la biologia de Hippodamia variegata (Goeze) (Coleoptera: Coccinellidae), especificamente en relacion a su ciclo vital, estacional y fluctuacion poblacional. Se determino que en condiciones de laboratorio este coccinelido requiere 190,32 ± 10,2 grados dias para completar una generacion, antecedente que sumado a los muestreos de campo permitio estimar que H. variegata completa cuatro generaciones por temporada en el cultivo de alfalfa (Medicago sativa L.).