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Recovery of Pseudomonas savastanoi pv. savastanoi from symptomless shoots of naturally infected olive trees
No full textSeasonal dynamics of Pseudomonas savastanoi pv. savastanoi (Psv) on stems and leaves from symptomless shoots of naturally infected olive trees was monitored in Spanish olive orchards. Data inferred from the comparison between washing of leaves and dilution-plating versus leaf printing of individual leaves suggested that Psv population sizes varied by over several orders of magnitude, among leaves sampled concurrently from the same shoot. We did not find significant differences between leaves and stems, in respect to the number of samples where Psv was isolated or detected by PCR, showing that Psv colonizes both leaves and stems. The frequencies of Psv isolation and average populations were highly variable among field plots. No correlation between Psv populations and those of non-Psv bacteria in any plant material or field plot was observed. However, where both Psv and yellow Pantoea agglomerans colonies were isolated a positive correlation was found. In a selected field plot, dynamics of Psv over three years showed significant differences between summer and the rest of seasons. The highest Psv population occurred in warm, rainy months, while low numbers were generally found in hot and dry months
A novel molecular approach to assess mating success of sterile Ceratitis capitata (Diptera: Tephritidae) males in sterile insect technique programs
No full textAreawide sterile insect technique (SIT) programs against Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), are increasingly implemented worldwide. A key issue in SIT is to assess mating success of released sterile males, which could be currently estimated by egg hatchability and by stored sperm head measurements. We report here on a novel molecular approach that would allow detecting the presence of Mediterranean fruit fly sterile male sperm in the female spermathecae under field conditions, as a precise marker to assess mating performance. The simplicity (only two polymerase chain reactions) and reliability of this method, jointly with the capability to detect Vienna sperm in wild Mediterranean fruit fly maintained in monitoring traps for 7 d under field conditions, suggest that it could be an efficient tool when coupled with areawide SIT programs
Efecto de la aplicación de rayos X a dosis moderadas sobre los componentes bioactivos de mandarinas "clemenules".
Get PDFLos cítricos son reconocidos por sus propiedades beneficiosas para la salud, principalmente debido a su alto contenido en vitamina C y a otros componentes bioactivos, la mayoría de ellos con actividad antioxidante. Las tecnologías poscosecha, además de extender la vida útil de las frutas y hortalizas, deben asegurar su calidad nutricional hasta llegar al consumidor. Entre las tecnologías poscosecha, la ionización con rayos X a dosis moderadas se presenta como una herramienta eficaz con gran potencial para extender la vida útil de frutas y hortalizas. En el caso de los cítricos españoles, también puede ser un tratamiento
cuarentenario eficaz contra la mosca mediterránea de la fruta Ceratitis capitata (Wiedemann). Con el propósito de evaluar el efecto del tratamiento con rayos X sobre los componentes bioactivos de mandarinas clementinas ‘Clemenules’ (Citrus reticulata Blanco), éstas se trataron con rayos X a 0, 195 y 395 Gy y se almacenaron a 20ºC o 5ºC durante 14 o 30 días respectivamente. Durante estos periodos se analizaron la capacidad antioxidante (método DPPH) y la vitamina C total y los flavonoides mayoritarios (hesperidina y narirutina) por cromatografía líquida de alta resolución (HPLC). En general, los tratamientos ionizantes empleados no ejercieron efecto en los parámetros analizados, por lo que su utilización no deteriora la calidad nutricional y funcional de mandarinas ‘Clemenules’
Sistemas de forzado en cultivo de boniato
Get PDFCon el fin de adelantar la producción, se han comparado, sobre cuatro cultivares, los siguientes métodos de forzado: - Acolchado con polietileno negro, -Acolchado con polietileno transparente, -Cubierta flotante (Agril) y Testigo sin protección. El diseño ha sido un split plot protección-cultivares, con dos repeticiones por combinación. La mayor producción comercial se ha conseguido con el acolchado negro. Con todos los métodos de forzado la producción ha sido mayor que en el suelo desnudo, pero las diferencias no han sido significativas. Tampoco ha habido interacción cultivar-protección. A diferencia de lo que sucede con el acolchado, con la cubierta flotante la colocación y retirada son sencillas
Comparación de métodos de injerto en sandía
Get PDFActualmente se ha comenzado a utilizar un nuevo procedimiento de injerto, «adosado», que presenta algunas variaciones respecto a los métodos anteriormente empleados (aproximación y púa). Con el fin de comparar el comportamiento en campo de las plantas injertadas con los tres procedimientos, se han injertado sandías del cultivar Reina (triploide) y Dulce Maravilla (diploide) sobre Shintoza (C. maxima x C. moschata) y se ha dispuesto un experimento con distribución de bloques al azar con cuatro repeticiones. La producción obtenida con las plantas con injerto adosado ha sido significativamente mayor que las obtenidas en plantas injertadas con los otros métodos. No se han detectado diferencias en tamaño del fruto
Efecto de la temperatura de almacenamiento y la aplicación de recubrimientos comestibles en la calidad postcosecha de ciruelas cv. ‘Sungold’ y ‘Angeleno’
Get PDFEl desarrollo de desórdenes fisiológicos y la pérdida de firmeza limitan la vida útil de las ciruelas en postcosecha. Además, algunos cv. como el ‘Sungold’ muestran una pérdida de calidad comercial debida a cambios en la coloración de la piel. El almacenamiento en frío combinado con el uso de atmósferas modificadas o recubrimientos comestibles reducen la pérdida de calidad de las ciruelas en postcosecha. En el presente trabajo se estudió el efecto de la temperatura y de la aplicación de recubrimientos comestibles en la calidad postcosecha de ciruelas cv. ‘Angeleno’ y ‘Sungold’. La funcionalidad de los recubrimientos comestibles depende, entre otros factores, de su composición. En ciruelas ‘Angeleno’ se estudió el efecto del tipo y contenido de ácido graso (AG) del recubrimiento en la calidad poscosecha. Para la formulación de estos recubrimientos se utilizó hidroxipropilmetil celulosa, cera de abeja (CA), glicerol y ácido graso (AG). Los AG estudiados fueron esteárico, palmítico y oleico, y la proporción de CA:AG fue 2:1 y 5:1. Las ciruelas recubiertas y las control se almacenaron 2, 4, 6 y 8 semanas a 1ºC, más 1 semana a 5ºC, más 5 días a 20ºC para su posterior análisis de calidad (CO2 interno, firmeza y desórdenes fisiológicos). En las ciruelas ‘Sungold’ se seleccionó la formulación CA:oleico (2:1) y se estudió el efecto de la temperatura de almacenamiento en la calidad. Las ciruelas recubiertas y las control permanecieron 1, 2, 3 y 4 semanas a 1ºC ó a 5ºC, más un día a 20ºC para su posterior análisis de calidad (color, firmeza y desórdenes fisiológicos). Las ciruelas ‘Angeleno’ recubiertas mostraron un incremento en los niveles de CO2 interno, mayor retención de firmeza y menor incidencia de bleeding. No se observó un efecto del tipo y contenido de AG de la formulación en los parámetros de calidad estudiados. En ciruelas ‘Sungold’ el almacenamiento a 1ºC preservó el color externo del fruto evitando el viraje de color de amarillo a rojo, mantuvo la firmeza del las ciruelas y redujo los desórdenes fisiológicos. El recubrimiento aplicado evitó el viraje de color y redujo la incidencia de daños por frío, pero no retuvo la firmeza de las ciruelas. Los resultados indican que la combinación de recubrimientos comestibles con un almacenamiento a temperaturas adecuadas pueden prolongar la vida útil de la ciruelas, reduciendo daños fisiológicos, pérdidas de textura y cambios de coloración de la piel
Preferential accumulation of severe variants of Citrus tristeza virus in plants co-inoculated with mild and severe variants
No full textThe viral population in sweet orange plants, either healthy or pre-inoculated with the asymptomatic isolate of Citrus tristeza virus (CTV) T32, and then graft- or aphid-inoculated with the stem-pitting isolate T318, was characterized with respect to symptom expression, reaction with monoclonal antibody MCA13, single-strand conformation polymorphism (SSCP) of genes p18 and p20, bi-directional RT-PCR, and dot-blot hybridisation. All plants inoculated with T318, with or without pre-inoculation, showed stem pitting, reacted with MCA13, had the SSCP profile characteristic of this isolate, and in bi-directional RT-PCR yielded a 450-bp DNA product associated with severe isolates, indicating that T32 afforded no protection against T318. The latter isolate had two main sequence variants, the minor one of which was indistinguishable from the main T32 sequence, and both were detected in most plants that were graft-inoculated with T318. However, the T32 variant was not detected in plants that were aphid-inoculated only with T318 and also showed stem pitting. This suggested an association of symptoms with the major T318 sequence and preferential transmission of this variant by aphids. The T318-specific variant accumulated more than the T32 variant in plants in which both were replicating, suggesting a higher fitness of the former. Our results clearly emphasize the potential threat of severe CTV variants in areas where mild isolates are presently predominant
Rice cv. Bahia mutagenized population: a new resource for rice breeding in the Mediterranean basin
Get PDFIn the Mediterranean basin, the limited availability of rice genetic resources restricts the success of breeding programs. Although mutation induction is a powerful alternative to generate desired novel variations, current rice mutant resources have little relevance in the Mediterranean breeding programs that require well-adapted cultivars for maximum performance. In this work a genome-wide mutation induction has been used on rice cv Bahia, a japonica cultivar well adapted to the Mediterranean climate and cultural practices, to increase its genetic variability and to facilitate the generation and selection of interesting agronomical traits. Bahia mutant collections were generated by irradiating seed batches with either 30 Gy fast neutrons or 250 Gy gamma rays. After initial screening of M2 plants and followed by evaluation of M3 and M4 generations in open field, elite genotypes were selected. The selected lines carried morphological and physiological changes of agronomical interest such as earliness, culm height reduction, yield increase and spontaneous spots appearance in leaves. The mutants are useful as breeding materials for improving varieties in the Mediterranean
Carcass condemnation causes of growth retarded pigs at slaughter
No full textCondemnation causes of growth retarded pigs were studied in a Spanish abattoir. A total of 513 carcasses out of 6017 (8.5%) were rejected during inspection. The main reasons for condemnation were abscesses, cachexia, catarrhal bronchopneumonia, vertebral osteomyelitis, arthritis, pleuritis, peritonitis and pleuropneumonia. Positive relationships were found between tail lesions and arthritis (OR = 5.23) or vertebral osteomyelitis (OR = 24.81), while no relationships were found between tail lesions and abscesses. Lower risks were observed among carcasses condemned for cachexia, and were as follows: abscesses (OR = 0.18), arthritis (OR = 0.32), vertebral osteomyelitis (OR = 0.06). Arcanobacterium pyogenes, either alone or in combination with other agents, was the main bacterial species isolated from abscesses, osteomyelitis and arthritis (73.5%, of lesions). Direct economical losses associated with condemnation were calculated to be is an element of 30,000. (c) 2006 Elsevier Ltd. All rights reserved
Analysis of 13000 unique Citrus clusters associated with fruit quality, production and salinity tolerance
Get PDFBackground: Improvement of Citrus, the most economically important fruit crop in the world, is extremely slow and inherently costly because of the long-term nature of tree breeding and an unusual combination of reproductive characteristics. Aside from disease resistance, major commercial traits in Citrus are improved fruit quality, higher yield and tolerance to environmental stresses, especially salinity. Results: A normalized full length and 9 standard cDNA libraries were generated, representing particular treatments and tissues from selected varieties ( Citrus clementina and C. sinensis) and rootstocks ( C. reshni, and C. sinenis x Poncirus trifoliata) differing in fruit quality, resistance to abscission, and tolerance to salinity. The goal of this work was to provide a large expressed sequence tag ( EST) collection enriched with transcripts related to these well appreciated agronomical traits. Towards this end, more than 54000 ESTs derived from these libraries were analyzed and annotated. Assembly of 52626 useful sequences generated 15664 putative transcription units distributed in 7120 contigs, and 8544 singletons. BLAST annotation produced significant hits for more than 80% of the hypothetical transcription units and suggested that 647 of these might be Citrus specific unigenes. The unigene set, composed of similar to 13000 putative different transcripts, including more than 5000 novel Citrus genes, was assigned with putative functions based on similarity, GO annotations and protein domains. Conclusion: Comparative genomics with Arabidopsis revealed the presence of putative conserved orthologs and single copy genes in Citrus and also the occurrence of both gene duplication events and increased number of genes for specific pathways. In addition, phylogenetic analysis performed on the ammonium transporter family and glycosyl transferase family 20 suggested the existence of Citrus paralogs. Analysis of the Citrus gene space showed that the most important metabolic pathways known to affect fruit quality were represented in the unigene set. Overall, the similarity analyses indicated that the sequences of the genes belonging to these varieties and rootstocks were essentially identical, suggesting that the differential behaviour of these species cannot be attributed to major sequence divergences. This Citrus EST assembly contributes both crucial information to discover genes of agronomical interest and tools for genetic and genomic analyses, such as the development of new markers and microarrays