ReDivia - Repositorio Digital de l'Instit Valencià d'Investigacions Agràries
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Analysis of population structure of Rosellinia necatrix on Cyperus esculentus by mycelial compatibility and inter-simple sequence repeats (ISSR)
No full textGenetic diversity was studied in a population of 24 isolates of Rosellinia necatrix obtained from Cyperus esculentus and 16 from other hosts by means of mycelial compatibility groups (MCGs) and inter-simple sequence repeat (ISSR) techniques. All isolates obtained from C. esculentus belonged to a unique MCG, irrespective of their geographical origin or year of isolation, and were incompatible with the isolates from other hosts. ISSR analysis gave results which were in agreement with the MCG determination; selected ISSR primers grouped a subset of eight representative isolates from C. esculentus in a unique cluster. The homogeneity found within the population of R. necatrix from C. esculentus in Valencia province could suggest that the pathogen was introduced recently and has spread further via infected tubers inadvertently used as propagating material, as well as by cull tubers swept away by irrigation water
Non-additive gene regulation in a citrus allotetraploid somatic hybrid between C. reticulata Blanco and C. limon (L.) Burm
No full textPolyploid plants often produce new phenotypes, exceeding the range of variability existing in the diploid gene pool. Several hundred citrus allotetraploid hybrids have been created by somatic hybridization. These genotypes are interesting models to study the immediate effects of allopolyploidization on the regulation of gene expression. Here, we report genome-wide gene expression analysis in fruit pulp of a Citrus interspecific somatic allotetraploid between C. reticulata cv ‘Willowleaf mandarin’+C. limon cv ‘Eureka lemon’, using a Citrus 20K cDNA microarray. Around 4% transcriptome divergence was observed between the two parental species, and 212 and 160 genes were more highly expressed in C. reticulata and C. limon, respectively. Differential expression of certain genes was confirmed by quantitative real-time RT-PCR. A global downregulation of the allotetraploid hybrid transcriptome was observed, as compared with a theoretical mid parent, for the genes displaying interspecific expression divergence between C. reticulata and C. limon. The genes underexpressed in mandarin, as compared with lemon, were also systematically repressed in the allotetraploid. When genes were overexpressed in C. reticulata compared with C. limon, the distribution of allotetraploid gene expression was far more balanced. Cluster analysis on the basis of gene expression clearly indicated the hybrid was much closer to C. reticulata than to C. limon. These results suggest there is a global dominance of the mandarin transcriptome, in consistence with our previous studies on aromatic compounds and proteomics. Interspecific differentiation of gene expression and non-additive gene regulation involved various biological pathways and different cellular components
Soil capacitance sensors and stem dendrometers. Useful tools for irrigation scheduling of commercial orchards?
Get PDFIrrigation scheduling is often performed based on a soil water balance, where orchard evapotranspiration is estimated using the reference evapotranspiration (ETo) times the crop coefficient (Kc). This procedure, despite being widely spread, has some uncertainties. Because of this, plant and soil water status monitoring could be alternatively or complementarily used to schedule irrigation. The usefulness of capacitance probes was evaluated during several seasons in large irrigation districts where irrigation practices were changed over years from the ETo * Kc model to the analysis of soil water status trend. This area corresponds to drip irrigated orchards planted with citrus, peach, nectarine and persimmon. Around 25% less irrigation was applied with no substantial yield penalty when the information provided by capacitance probes was correctly applied for irrigation management. On the other hand, the usefulness of stem dendrometers for continuously monitoring plant water status was evaluated in a young plum experimental orchard. Over two years, irrigation was scheduled using exclusively trunk shrinkage via the signal intensity approach by means of a baseline equation previously obtained in the orchard. Results showed that it was not always possible to schedule irrigation based on the trunk shrinkage signal intensity due to the temporal changes in the reference values that occurred as trees aged. Overall, results obtained are discussed in terms of the possible extrapolation at field level of both capacitance probes and stem dendrometers. Advantages and drawbacks of each technique are analyzed and discussed
Spray Deposition and Efficacy of Four Petroleum-Derived Oils Used Against Tetranychus urticae (Acari: Tetranychidae)
No full textPetroleum-derived spray oils (PDSOs) offer an interesting alternative to acaricides to control the twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), a key pest of clementine mandarins, Citrus reticulate Blanco. However, there is a lack of knowledge on how these products should be used. In this study, we evaluated the efficacy of four PDSOs (Sunspray Ultrafine, Volck Miscible, Texaco D-C-Tron Plus, and Agroaceite) at five concentrations (0.5, 1.0, 1.5, 2.0, and 3.0%) against eggs, protonymphs, and adults of T. urticae. We also characterized the PDSOs deposition pattern to find out the possible relationship between this factor and efficacy. In general, for all PDSO assayed, the higher the concentration, the higher the coverage, the mean area of impacts and efficacy on T. urticae. The biggest mean area of the impacts corresponded to Texaco D-C-Tron Plus. This PDSO was the most effective one and its efficacy was independent of concentration for concentrations higher than 1.0%. The same applied for concentrations higher than 1.5-2.0% for Agroaceite, Volck Miscible, and Sunspray Ultrafine, with high efficacies against eggs, protonymphs, and adults. PDSOs are highly effective against T. urticae, the use of these products should be encouraged in integrated citrus pest management programs in Spain. The next step will be to ascertain the efficacy under real field conditions
Real-time inspection of fruit on a mobile haresting platform in field conditions using computer vision
No full textThe best alternative for reducing citrus production costs is mechanization. Machine
vision is a reliable technology for the automatic inspection of fresh fruits and vegetables
that can be adapted to harvesting machines. In these, fruits can be inspected before sending them to the packinghouse and machine vision provides important information for
subsequent processing and avoids spending further resources in non-marketable fruit.
The present work describes a computer vision system installed on a harvesting machine
developed jointly by IVIA and a Spanish enterprise. In this machine, hand pickers directly drop the fruit as they collect it, which results in an important increase of productivity. The machine vision system is placed over rollers in order to inspect the produce,
and separate those that can be directly sent to the fresh market from those that do not
meet minimal quality requirements but can be used by the processing industry, based on
color, size and the presence of surface damages. The system was tested under field conditions
Adoption of Soilless Cropping Systems in Mediterranean Greenhouses: An Application of Duration Analysis
Get PDFThe Mediterranean basin holds the greatest area of horticultural crops grown under plastic in the world. Spain houses almost 50,000 ha of greenhouses and is one of the largest suppliers of European Union markets. Soilless cropping systems constitute all efficient production practice used in greenhouses and lessen the limitations arising from the ban of methyl bromide. Soilless cultivation is associated with the use of expensive technology, which makes farmers consider such adoption carefully. The aim of this work is to statistically identify the factors that significantly influence the timing of adopting soilless cultivation by using duration analysis. The study focuses on Mediterranean greenhouses, specifically horticultural producers in the southeast of Spain. The results suggest that certain individual characteristics as well as aspects of a social nature exert a favorable influence by reducing the delay in adopting soilless cultivation. Furthermore, technical complexity, commercial aspects related to price, and the repercussion of policies regulating methyl bromide use are also discussed in this work
Development of a bioacoustic sensor for the early detection of Red Palm Weevil (Rhynchophorus ferrugineus Olivier)
No full textThe Red Palm Weevil (Rhynchophorus ferrugineus Olivier) is one of the worst pests for palms, since it can completely destroy the plant. Its early detection is very difficult and when the action of the pest is discovered, normally it is too late for recovering the plant. Bioacoustic sensors provide a good alternative for early detection of this pest because larvae activity is audible while they excavate tunnels to feed. This work describes the different stages for the development of an original electronic device based on acoustic sensors for early detection of Red Palm Weevil larvae in the interior of palms. This device is based on characteristic frequencies possibly related to their feeding activity. The performed tests have demonstrated that is possible to detect two week old larvae activity studying the sound intensity around 2250 Hz in palms infested only with 5 individuals under controlled environmental conditions. The activity of other insects artificially situated in the interior of palms did not affect the response of the device, possibly because they produce different frequencies (in the range 5-7 kHz). Future work will be aimed at assessing the infestation levels. (C) 2010 Elsevier Ltd. All rights reserved
Estudio Diagnóstico sobre la Biodiversidad Cultivada y la Agricultura Ecológica en Andalucía, Asturias, Comunidad Valenciana, Galicia y Región de Murcia
Get PDFEl proyecto Agricultura Ecológica, Fuente de Empleo Rural "AEFER", consiste en
la realización de una serie de acciones encaminadas a promover el establecimiento y la
conversión de agricultores y sus empresas a la producción y transformación agraria
ecológica. El proyecto AEFER está promovido por la Sociedad Española de Agricultura
Ecológica SEAE, cofinanciado por el Fondo Social Europeo y enmarcado en el Programa
Empleaverde 2007-2013 de la Fundación Biodiversidad. Este proyecto tiene como
objetivo general contribuir a una mayor sostenibilidad (ecológica, económica y social) de
los sistemas agrarios, mejorando la calidad de vida de los agricultores, promoviendo la
conversión de sus tierras a la agricultura ecológica, diversificando y ampliando las
actividades agrarias. El proyecto se desarrolla en 5 Comunidades Autónomas: Andalucía,
Asturias, Comunidad Valenciana, Galicia y Región de Murcia.
Para cumplir con estos objetivos se contemplan una serie de acciones, entre las
que se incluye el presente “Estudio Diagnostico sobre Biodiversidad Cultivada y
Agricultura Ecológica” elaborado por la Red de Semillas “Resembrando e
Intercambiando”. La Red de Semillas, es una organización descentralizada de carácter
técnico, social y político, que ha trabajado durante los últimos 10 años en reunir esfuerzos
entorno al uso y conservación de la biodiversidad agrícola en el contexto local, estatal e
internacional, y que tiene como objetivo primordial el facilitar y promover el uso,
producción, mantenimiento y conservación de la biodiversidad agrícola en las fincas de
los agricultores y en la alimentación de los consumidores.
Este estudio ha posibilitado la puesta en marcha diferentes iniciativas que, a modo
de proyectos piloto, puedan permitir en el futuro evaluar la situación de la utilización de los
recursos genéticos agrícolas. Se han incluido tanto experiencias de campo con
agricultores tradicionales y/o ecológicos como recursos conservados en los bancos de
semillas institucionales
Brief gaseous shocks to inhibit postharvest gray mold on 'Mollar de Elche' pomegranates
No full textSpain is the first European Union producer and exporter of pomegranates
(Punica granatum L.) and ‘Mollar de Elche’ is the most important cultivar.
Studies show remarkable benefits from pomegranate consumption on human
health mainly due to the high antioxidant activity of this fruit. As new markets
based on the manufacture of derived functional food products are arising,
longer storage life of fresh pomegranates is demanded. Decay due to gray
mold, caused by Botrytis cinerea, is one of the most important factors limiting
storability of pomegranates. In Spain, no postharvest chemical treatments are
permitted and alternative antifungal methods are required. In this work,
pomegranates cv. ‘Mollar de Elche’ were artificially inoculated with B.
cinerea and exposed 24 h later to air (control), 95 kPa CO2, or 30 kPa O2 + 70
kPa CO2 at 20°C and 90% RH for 48 h, and subsequently stored at either
20°C for 12 days or 5°C and 90% RH for 2.5 months. On pomegranates
incubated at 20°C, exposure to 95 kPa CO2 reduced gray mold incidence by
97 and 63% compared to control fruit after 2 and 5 days, respectively.
However, this reduction gradually decreased along the incubation period.
Decay incidence was not significantly reduced on pomegranates treated with
the mixture 30 kPa CO2 + 70 kPa CO2. On pomegranates stored at 5°C, both
gaseous shocks reduced gray mold incidence by 80 and 40% after 12 and 26
days of storage, respectively, but the treatments lacked persistence
El cultivo ecológico de alcachofa en su doble utilidad productiva y seguridad alimentaria
Get PDFLa alcachofa (Cynara scolymus L.) es un cultivo de gran importancia en la
Comunidad Valenciana y forma parte habitualmente de las rotaciones en las zonas de
huerta. Para el cultivo ecológico puede ser de gran utilidad, además de la producción de
capítulos para su consumo humano, por la elevada biomasa que produce su cultivo; y de
esta forma, servir como abono verde al enriquecer el suelo con abundante materia
orgánica y su elevada función de sumidero de gases efecto invernadero (GEI).
Se compara el comportamiento agronómico de distintos cultivares de alcachofa de
semilla con los obtenidos en la parcela de cultivo convencional dentro de la misma finca y
similares condiciones; valorando la producción de biomasa procedente del cultivo y las
incidencias fitosanitarias.
El cultivo ecológico de la alcachofa de semilla, puede compararse en su
producción al cultivo convencional y sin aplicación de fitosanitarios durante todo el cultivo,
representando un alto valor en el enriquecimiento de materia orgánica del suelo, al
producir un nivel de biomasa como abono verde de 4,63 Kg/planta, equivalente a 2,039
Kg de materia seca por m2 y a 42,08 t/ha. y año de CO2 secuestrado en el suelo