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Molecular tools in the evaluation of SIT programmes success against Ceratitis capitata in Spain: a review
Get PDFBackground: The success of sterile insect technique (SIT) programs against many tephritid
fruit flies, including Ceratitis capitata (Wiedemann), relies on the mating success of released
sterile males in the field. Since its´ development in an area-wide concept, this control program
is evaluated by the recapture ratio of sterile versus wild flies. This measure neither takes into
account the real target of the SIT that is the wild female, nor does it give any clue about the
success of released sterile males. Thus, the contribution of released sterile males to reduce the
wild population still remains as a key issue. In this work we review recent findings on how
sterile males contribute to reduce wild populations by means of analyzing the sperm content
of wild females, as the real target of the SIT program.
Methods: A mating competition test was initially performed in laboratory and then under
semi-natural conditions, with different Ceratitis capitata Vienna-8 tsl release ratios. The
efficacy of the SIT and its contribution to reduce wild population was assessed by
determining the percentage of females mated with sterile male, with a sperm ID molecular
test, and by linking to offspring production on sentinel hosts.
Results: Statistical methods have been developed with the obtained data of sperm ID in the
spermathecae of captured females and with data of viable offspring produced in sentinel
fruits, revealing that both can be predicted using release ratio and mean temperature.
Moreover, humidity arose also as a factor influencing the female capture in lured traps. A
strong negative relationship was established between the proportion of Vienna-8 mated
females and Ceratitis capitata offspring production, being a key point for a model to predict
the SIT program success.
Conclusions: The statistical models developed should contribute to enhance the efficacy of
SIT programs against Ceratitis capitata by means of modulation of release ratios by season
temperature and by checking wild female’s sterile sperm content
Ralentización del proceso de maduración en Bobal y Tempranillo mediante deshojado tardío y riego: efectos sobre la composición de la uva y del vino
Get PDFLos efectos del cambio climático en la vitivinicultura mediterránea están
resultando negativos, pues desacoplan la madurez tecnológica de la uva de la
fenólica. Tal circunstancia afecta especialmente a variedades tintas, dando lugar a
vinos de elevada graduación alcohólica y bajo contenido en compuestos fenólicos,
aspectos que se asocian a baja calidad. El objetivo de este ensayo fue ralentizar
las dinámicas de maduración de la uvas en las variedades Bobal y Tempranillo
mediante la reducción del ratio fuente:sumidero, y así hacerlas coincidir con
periodos más frescos. Para este fin, se estudiaron los efectos que las técnicas de
riego deficitario frente al secano y del deshojado realizado antes de envero
provocaron sobre el rendimiento de las cepas y la composición de la uva, durante
dos años. Los resultados de las parcelas experimentales localizadas en Requena
(Valencia) ponen en evidencia la gran influencia que el riego tiene sobre el estado
hídrico de las cepas. A su vez, la reducción de área foliar tendió a atenuar el
estrés hídrico. No obstante, estos incrementos no evitaron ligeras mermas
productivas debidas a reducciones del tamaño de baya en algunos tratamientos
deshojados. La respuesta al riego de la evolución en la acumulación de azúcares
fue opuesta según la variedad. Sin embargo, el 40 % de reducción del área foliar
la ralentizó significativamente en ambas variedades, retrasándose la vendimia
como mínimo siete días. La concentración de antocianos y el índice de polifenoles
totales en los mostos tendieron a reducirse en la variedad Bobal por el efecto del
riego, y ligeramente en ambas variedades por los efectos del deshojado, así como
en sus vinos. Por tanto, las dos técnicas resultaron eficaces para modular la
evolución de la maduración de la uva de estas dos variedades tintas en
condiciones semiáridas. Si bien, los resultados del deshojado tardío sobre la
composición fenólica no fueron los esperados
Valor fertilizante de los restos de cosecha en un cultivo de coliflor de ciclo largo
Get PDFEn los cultivos hortícolas, los restos de cosecha suelen tener un elevado
contenido de nitrógeno orgánico que origina una cantidad importante de nitrógeno
mineral a través de su mineralización. Los restos de coliflor, debido a su elevada
cantidad y alto porcentaje de N, son un ejemplo claro del potencial fertilizante de
estos materiales. Por ello, es necesario determinar la cantidad de N aportado y la
cinética de su mineralización tras el enterrado de los restos de cosecha, para poder
determinar las necesidades de abonado nitrogenado del siguiente cultivo de la
rotación. En este trabajo se muestran los valores de mineralización de N obtenidos
en condiciones controladas de laboratorio y en condiciones de campo tras la
incorporación al suelo de los restos del cultivo de coliflor. La incorporación de estos
restos al suelo supuso un aporte adicional de nitrógeno que, en condiciones de
campo, osciló entre 30-110 kg N ha-1. La mineralización obtenida en los ensayos de
laboratorio en condiciones controladas de temperatura y humedad fue mayor que la
obtenida en campo
Desarrollo de métodos biotecnológicos aplicados a la mejora genética del níspero japonés (Eriobotrya japonica (Thunb.) Lindl.)
Get PDFEn el contexto del programa de mejora genética que se lleva a cabo en el IVIA, en esta tesis se han desarrollado una serie de herramientas que implementen el programa y permitan aumentar la eficacia del mismo. En primer lugar, se ha estudiado la diversidad genética de la colección de germoplasma del IVIA, por medio de marcadores moleculares tipo microsatélites, ya que los recursos fitogenéticos son la principal herramienta de la mejora. Combinando 3 tipos de análisis: Análisis Factorial de Correspondencia, método de agrupamiento Bayesiano y UPGMA se ha determinado la estructura poblacional de la colección. Se han obtenido 5 subpoblaciones relacionadas con los orígenes de las accesiones. Las distancias genéticas obtenidas y los análisis de agrupación sugieren que las accesiones introducidas en la cuenca mediterránea procederían de Asia. Por otra parte, se han obtenido 3 subpoblaciones formadas por accesiones de origen europeo que demuestran la alta diversificación varietal y la adaptación de la especie en los países mediterráneos a pesar de su tardía introducción en Europa. También el análisis de los alelos de compatibilidad ha aportado información sobre el movimiento de germoplasma y ha contribuido a conocer los grupos de intercompatibilidad dentro de la colección. La información genética generada complementa la fenotípica obtenida previamente por el IVIA y será de gran ayuda en la planificación de los futuros cruzamientos del programa. Otra herramienta biotecnológica para implementar el programa de mejora ha sido la puesta a punto de técnicas para aumentar la diversidad basada en genotipos con diferentes niveles de ploidía. Por una parte, se ha utilizado la mutagénesis química con colchicina y posterior selección in vitro con el objetivo de obtener poliploides, de gran interés en níspero, ya que puede dar lugar a variedades con frutos de mayor tamaño (tetraploides) o frutos sin semilla (triploides). Se obtuvieron poliploides estables sumergiendo las semillas sin germinar en una solución de colchicina, dos triploides (3x) posiblemente ya presentes en el lote de semilla híbrida de partida, y un tetraploide (4x). El nivel de ploidía se determinó primero mediante citometría de flujo, y los resultados se confirmaron posteriormente por conteo cromosómico en hoja, ápice radicular, y evaluación morfológica. Por otro lado, con la finalidad de obtener haploides y doble-haploides (DH), se ha estudiado la capacidad de inducción de embriogénesis gametofítica en ambos tipos de gametos, masculinos (cultivo de microsporas aisladas y anteras) y femeninos (partenogénesis in situ inducida por polen irradiado). La producción de líneas puras mediante técnicas biotecnológicas en una única generación, es especialmente útil en especies de largo periodo intergeneracional como el níspero. Los genotipos haploides permiten obtener individuos homocigotos en un solo paso, facilitan estudios genéticos, alineamiento de secuencias y explotar el vigor híbrido. En los experimentos de cultivo de microsporas aisladas se consiguió inducir callogénesis en diversas accesiones de la especie, siendo el primer paso hacia la respuesta morfogénica. El cultivo de anteras ha dado lugar a una plántula triploide (3x), posiblemente debido a una duplicación cromosómica espontánea durante el proceso de regeneración, y ha permitido demostrar que es posible la inducción de embriogénesis en níspero aunque hay muchos factores que influyen en la respuesta. Mediante partenogénesis in situ con polen irradiado con rayos gamma, y posterior rescate y cultivo de embriones in vitro ha sido posible obtener cuatro plantas haploides. El nivel de ploidía se determinó primero mediante citometría de flujo, los resultados se confirmaron posteriormente por conteo cromosómico en hoja
A simple, fast and inexpensive method to assess salt stress tolerance of aerial plant part: Investigations in the mandarin group
No full textFor grafted plants, salt stress tolerance of the aerial plant part is poorly documented. Thus, we developed a simple, fast and inexpensive method to identify tolerant genotypes. Twigs of 14 mandarin accessions that we previously analyzed as seedlings were cut in solution to prevent embolism and were then evaluated in salt stress condition for a week. Physiological parameters such as gas exchanges, leaf Cl- and Na+, as well as the presence of H2O2 and the activity of enzymes involved in ROS synthesis and detoxification processes were analyzed. One accession known to be tolerant as rootstock was shown to be sensitive with limited Cl- translocation from the solution to the shoot while sensitive accessions when grown as seedlings presented limited wilting symptoms and accumulated large leaf Cl- content. A model is proposed to explain the different strategies of the plant to cope with high toxic ion content. This method allows separation of the root compartment, where ion exclusion mechanisms may exist and have an impact on the salt stress tolerance of the whole plant
Does the inclusion of protease inhibitors in the insemination extender affect rabbit reproductive performance?
Get PDFThe bioavailability of buserelin acetate when added to the seminal dose appears to be determined by the activity of the existing aminopeptidases. Thus, the addition of amino peptidase inhibitors to rabbit semen extenders could be a solution to decrease the hormone degradation. This study was conducted to evaluate the effect of the protease activity inhibition on rabbit semen quality parameters and reproductive performance after artificial insemination. Seminal quality was not affected by the incubation with protease inhibitors, being the values of motility, viability, and acrosome integrity not significantly different between the protease inhibitors and the control group. In addition, seminal plasma aminopeptidase activity was inhibited in a 55.1% by the protease inhibitors. On the other hand, regarding the effect of protease inhibitors on reproductive performance, our results showed that the presence of protease inhibitors affected the prolificacy rate (9.2 +/- 0.26 and 9.3 +/- 0.23 vs. 8.2 +/- 0.22 total born per litter for negative control, positive control, and aminopeptidase inhibitors group, respectively; P < 0.05), having this group one kit less per delivery. We conclude that the addition of a wide variety of protease inhibitors in the rabbit semen extender negatively affects prolificacy rate. Therefore, the development of new extenders with specific aminopeptidase inhibitors would be one of the strategies to increase the bioavailability of GnRH analogues without affecting the litter size
Placement density and longevity of pheromone traps for monitoring of the citrus leafminer (Lepidoptera: Gracillariidae)
Get PDFThe citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is an important pest of all citrus varieties. Larvae damage young
leaves, thereby reducing photosynthesis and tree vigor, and may impact yield. Wounds opened by P. citrella larvae may also increase susceptibility to
citrus canker disease caused by the bacterium Xanthomonas axonopodis pv. citri (Xanthomonadales: Xanthomonadaceae). Sex pheromones coupled
with appropriate traps are used as monitoring tools for this and other lepidopteran pests. Information compiled from trap captures is indicative of
seasonal population fluctuations and may be used to guide management practices. Trap density and pheromone dispenser longevity are factors
affecting the accuracy of trapping data. Our objectives were to evaluate capture of P. citrella in relation to trap density and duration under field
conditions. Almost 2 yr of citrus leafminer monitoring demonstrated that a density of 1 trap per approximately 2 ha yielded similar results to the
higher recommended density of 1 trap per 0.4 to 1.6 ha. Trap catch with the 2 pheromone brands tested declined by 25% after 3 to 6 wk and 50%
after 6 to 10 wk during the spring through fall growing season in Florida. Therefore, correction factors are required if traps are replaced at 8 to 13
wk intervals. Results of the present study will help optimize monitoring programs that can serve as early warning of potential damaging populations
of P. citrella
Induced parthenogenesis by gamma-irradiated pollen in loquat for haploid production
Get PDFSuccessful haploid induction in loquat (Eriobotrya japonica (Thunb.) Lindl.) through in situ-induced parthenogenesis with gamma-ray irradiated pollen has been achieved. Female flowers of cultivar ‘Algerie’ were pollinated using pollen of cultivars ‘Changhong-3’, ‘Cox’ and ‘Saval Brasil’ irradiated with two doses of gamma rays, 150 and 300 Gy. The fruits were harvested 90, 105 and 120 days after pollination (dap). Four haploid plants were obtained from ‘Algerie’ pollinated with 300-Gy-treated pollen of ‘Saval Brasil’ from fruits harvested 105 dap. Haploidy was confirmed by flow cytometry and chromosome count. The haploids showed a very weak development compared to the diploid plants. This result suggests that irradiated pollen can be used to obtain parthenogenetic haploids
Effects of long-term summer deficit irrigation on ‘Navelina’ citrus trees
Get PDFThe effects of long-term summer deficit irrigation (RDI) strategies on ‘Navelina’ orange trees (Citrus sinensis L. Osbeck) were assessed in a drip-irrigated commercial orchard located in Senyera (Valencia, Spain). Three irrigation treatments were applied during five consecutive years (2007–2011): a control treatment, without restriction, and two RDI treatments, in which the water reduction was applied during the summer (initial fruit enlargement phase). During the first three seasons, the trees under the control treatment received 110% of the theoretically required irrigation dose (ID), and the RDI treatments received 40% and 60% of the full ID during the deficit period. During the last two years of the study, the control treatment was irrigated at 100% of the ID and the amount of water applied in the RDI treatments was additionally decreased 20% from the reduced ID of the preceding years. The crop’s response to summer deficit irrigation was analysed in relation to tree water status, which was assessed by relying on midday stem water potential (Ψst). The lowest Ψst values were reached, as expected, at the end of the water deficit period and with the most stressed treatment. These minimum Ψst values ranged between −1.6 MPa in 2008 and −2.5 MPa in 2010. In most occasions, the trees under RDI treatments showed a fast hydric recovery and had completely re-hydrated one week after restarting irrigation. Summer RDI treatments did not cause negative effects on either the amount or on the quality of the yield if the threshold value of Ψst = −2.0 MPa was not surpassed. According to the results, it can be concluded that long-term RDI strategies may be applied successfully on Navelina orange trees during summer without negatively affecting the studied parameters while allowing water savings between 12% and 27%
VIS/NIR hyperspectral imaging and N-way PLS-DA models for detection of decay lesions in citrus fruits
Get PDFIn this work an N-way partial least squares regression discriminant analysis (NPLS-DA) methodology is developed to detect symptoms of disease caused by Penicillium digitatum in citrus fruits (green mould) using visible/near infrared (VIS/NIR) hyperspectral images. To build the discriminant model a set of oranges and mandarins was infected by the fungus and another set was infiltrated just with water for control purposes. A double cross-validation strategy is used to validate the discriminant models. Finally, permutation testing is used to select a few bands offering the best correct classification rates in the validation set. The discriminant models developed here can be potentially implemented in a fruit packinghouse to detect infected citrus fruits at their arrival from the field with affordable multispectral (3–5 channels) cameras installed in the packinglines