ReDivia - Repositorio Digital de l'Instit Valencià d'Investigacions Agràries
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Evaluation of ultrasonic parameters as a non-invasive, rapid and in-field indicator of water stress in Citrus plants
Get PDFNon-Contact Resonant Ultrasound Spectroscopy (NC-RUS) has emerged as a powerful tool to determine plant water status in a non-destructive, non-invasive and rapid way. In this study, ultrasonic parameters directly obtained from experimental measurements in the field using NC-RUS - such as resonant frequency (fres), velocity (v) and Q-factor - were evaluated as potential water stress indicators in Citrus plants. The experiments were carried out in two-year-old mandarin trees (Citrus clementina Hort. ex Tan. ‘Clemenules’) grown in pots in an open greenhouse where two different groups of plants were tested: a Control group (full irrigation) and a Drought Stress group (DS) whose irrigation was withdrawn during 7 days, followed by a 16 days recovery period. Soil water content, leaf water potential (Ψleaf) and the considered ultrasonic parameters were measured in the same leaves. fres detected changes between control and DS at day 7 without irrigation. Conversely, v showed differences after day 3, which were statistically significant at day 7, enabling discrimination between C and DS groups. Hence, Q-factor was the ultrasonic parameter that showed statistically significant differences between C and DS groups at days 3 and 7. Consequently, Signal Intensity in Q during the drought treatment showed a similar evolution to Ψleaf, although with slightly lower performance. However, Q-factor sensitivity excels Ψleaf at each day studied. Finally, a linear correlation (R2=0.57) between Ψleaf and Q-factor of all experimental data measured in DS group plants along the drought treatment was found. In conclusion, the ultrasonic parameters obtained using NC-RUS and in particular the Q-factor, demonstrated to be potential new water stress indicators in Citrus trees, with the novelty of being non-destructive, non-invasive and rapid. Future work should explore its suitability for its use in irrigation scheduling for Citrus tree
Isolation and characterization of bacteriophages against Xylella fastidiosa
Get PDFBacteriophage viruses are a promising tool for preventing and treating bacterial infections. In this sense, phage therapy is an eco-sustainable approach that has the potential to be used as either an alternative or a complement to other strategies for the management of Xylella fastidiosa diseases. The main objective of this work was the search, isolation, selection and characterization of bacteriophages against this phytopathogenic bacterium
Exploring the potential for the selective breeding of Nesidiocoris tenuis: a study of its genetics and feeding behavior
Get PDFNesidiocoris tenuis (Reuter) (Hemiptera: Miridae) is a cosmopolitan zoophytophagous predator, which zoophagy and phytophagy have given it both the status as biocontrol agent and pest, respectively. Thus, it fits into the category of biocontrol agents with traits that hinder its performance. In regions where it is valued as a biocontrol agent, it is mainly released in tomato crops to suppress key pests such as Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) and Tuta absoluta Meyrick (Lepidoptera: Gelechiidae). Its role in the activation of plant defenses has also been confirmed more recently. However, its phytophagous behavior can inflict damage on tomato crops under circumstances of prey scarcity. This can produce esthetical or yield losses, or lead to the application of pesticides to reduce its population, thus disrupting the biocontrol programs. Selective breeding in N. tenuis have been suggested as an alternative to minimize the detrimental effects of its phytophagy, however, no genetic or genomic information on the species was reported to date
Effect of delaying winter pruning of Bobal and Tempranillo grapevines on vine performance, grape and wine composition
Get PDFBackground and Aims: Climate change is advancing grapevine phenology, decoupling berry technological and phenolic maturity. The aim of this study was to assess the usefulness of late winter pruning for delaying grape ripening. Methods and Results: In two Bobal and Tempranillo vineyards located in eastern Spain, vines pruned at dormancy were compared with a delayed winter pruning (late pruning) carried out just before the basal buds burst (BBCH 05). In both cultivars, late pruning delayed grape ripening, resulting in grapes with higher anthocyanin concentration for similar TSS at harvest. In general, the resulting wines had a higher colour intensity and lower hue angle. These effects were more noticeable in Tempranillo, an earlier ripening cultivar, than in Bobal. Despite late pruning improving vine water status, the yield was steadily reduced by 10%. Conclusions: Late pruning is a useful strategy for delaying grape ripening, thus adapting grapevine production to climate change. The small detrimental effects on yield and compression of pruning dates within a few days may limit the application of this practice. Significance of the Study: Delaying winter pruning can be used to improve grape and wine composition when facing changes in the meteorological conditions experienced during berry ripening
Comportamiento agronómico de nuevas variedades de granado (Punica granatum L.) en la Plana Baixa de Castellón
Get PDFLa escasa rentabilidad que arrastra en los últimos años el sector citrícola en la Comunidad Valenciana ha impulsado la búsqueda por parte de los agricultores de cultivos alternativos. En este escenario, el granado es un frutal que apoyado en la aparición de nuevas variedades se posiciona como potencialmente interesante, pero que necesita de una experimentación previa a la plantación comercial en condiciones agroecológicas diferentes a la de las zonas tradicionales. El presente trabajo es un estudio comparativo de la adaptación de este cultivo a la comarca de la Plana Baixa de Castellón. Están siendo evaluados los siguientes cultivares: tres variedades híbridas registradas por el IVIA (‘Iliana’, ‘Rugalate’ y ‘H-621’), tres selecciones clonales de variedades tradicionales ‘Mollar’ (M-55, M-49) y ‘Valenciana’ (V-111); y dos variedades consolidadas a nivel internacional (‘Acco’ y ‘Wonderful’). La plantación se realizó en 2016, y se han obtenido datos de fenología, producción, desarrollo de la planta, eficiencia productiva, y del fruto las características morfológicas, físico-químicas y la calidad sensorial. Se ha calculado la integral térmica de cada variedad para que el fruto alcance la madurez comercial. Los primeros resultados indican un buen comportamiento general de todas las variedades, destacando la precocidad de ‘Iliana’, calidad del zumo de ‘Rugalate’; y la productividad y el tamaño del fruto de ‘Wonderful’
Curative activity against citrus postharvest green mold of composite hydroxypropyl methylcellulose-beeswax edible coatings with zeolites containing Ag-nanoparticles
Get PDFTwo types of commercial Na-zeolites, linde type A (LTA) and faujasite (FAU) were prepared with different percentage of silver that was incorporated by ion exchange using solutions of AgNO3. The physico-chemical properties of the samples were established using different techniques such as atomic emission spectroscopy with inductively coupled plasma (ICP-OES), X-ray diffraction (XRD), electronic microscopy (SEM and EDX), and temperature-programmed reduction (TPR). The curative activity of these materials was first evaluated as water dispersions in in vivo primary screenings by placing a drop (30 µL) in a rind wound of 'Valencia' oranges that had been inoculated 24 h before with a conidial suspension of Penicillium digitatum. Selected Ag-zeolites were incorporated as antifungal ingredients at different concentrations into composite hydroxypropyl methylcellulose (HPMC)-beeswax (BW) edible emulsions prepared with 8% total solid content with stearic acid as emulsifier and glycerol as plasticizer. Depending on the experiment, these coatings were applied 24 h after fungal inoculation to 'Valencia' oranges as drops in rind wounds or covering the entire fruit. Controls included inoculated but untreated fruit and inoculated fruit treated with HPMC-BW without Ag-zeolites. After incubation of treated fruit at 20°C for 7 days, coatings amended with Ag-zeolites reduced the incidence and severity of green mold by more than 80%, showing high potential for effective disease control. Curative activity depended on Ag concentration and FAU zeolites were more effective than LTA zeolites, probably because of their larger pore apertures and higher Si/Al ratio that favored silver diffusion. However, coatings with the highest silver content were phytotoxic causing dark blemishes on the fruit rind. Further work is needed to optimize non-phytotoxic coatings with the highest curative activity
Aproximaciones al cultivo de ‘Candidatus Liberibacter solacearum
Get PDF'Candidatus Liberibacter solanacearum' (CaLso) es una bacteria Gram negativa asociada a desórdenes vegetativos en cultivos estratégicos como patata, zanahoria, tomate, apio, pimiento y chirivía. Estos desórdenes pueden modificar el aspecto de los tubérculos, las raíces y los frutos de las plantas infectadas, afectando a su comercialización. Esta bacteria está restringida al floema de las plantas hospedadoras y a la hemolinfa de los psílidos que se alimentan de las mismas, constituyendo la principal vía de transmisión
Selección y caracterización de bacterias asociadas a plantas con actividad antagonista frente a Erwinia amylovora
Get PDFErwinia amylovora, agente causal del fuego bacteriano de las rosáceas, es una bacteria de fácil diseminación que coloniza especies vegetales de gran importancia económica, como manzano, peral, níspero y membrillero, y que es difícil de controlar mediante prácticas de cultivo y agroquímicas. La búsqueda de estrategias de gestión alternativas que sean eficaces y eco-sostenibles ha llevado a la utilización de microorganismos para establecer programas de control biológico
Efecto del diluyente, condiciones de conservación de los eyaculados y metodología de análisis empleada, sobre la cinética espermática determinada mediante casa, en toros pura raza Wagyu
Get PDFLa raza japonesa Wagyu se cría de manera casi exclusiva en Japón, Australia y EE.UU. y de manera esporádica se exportan embriones y genética a diferentes partes del mundo. De este modo, la tasa de consanguinidad en rebaños de Wagyu, fuera de Japón, es elevada y por ello, los estudios sobre calidad espermática y conservación seminal en esta raza son fundamentales (Kanno et al. 2017). En esta línea, el diluyente, tiempo y temperatura de conservación de las muestras seminales hasta el análisis y metodología analítica utilizada, afectan a los resultados obtenidos en la cinética espermática determinada mediante CASA en eyaculados bovinos (Garcia-Paloma et al., 2016; Bompart et al., 2019). El objetivo de este estudio fue comparar diferentes dispositivos (portaobjetos; cámaras Makler® e ISAS®D4C20), diluyentes (AndroMed®; BioXcell®), tiempo hasta el análisis (0h; 4h) y condiciones de mantenimiento (5ºC; temperatura ambiente con AndroMed®) sobre los parámetros CASA de un mismo eyaculado de toros de esta raza tan escasa en España
Antifungal Hydroxypropyl Methylcellulose (HPMC)-Lipid Composite Edible Coatings and Modified Atmosphere Packaging (MAP) to Reduce Postharvest Decay and Improve Storability of ‘Mollar De Elche’ Pomegranates
Get PDFPomegranate exhibits important postharvest quality losses that limit its storage potential, caused mainly by weight loss, chilling injury and fungal diseases. In this work, we evaluated the effect of novel hydroxypropyl methylcellulose (HPMC) edible coatings (ECs) formulated with three different lipids (beeswax (BW), carnauba wax, and glycerol monostearate), as hydrophobic components, and two different GRAS salts (potassium bicarbonate (PBC) and sodium benzoate (SB)), as antifungal ingredients, to control weight loss and natural fungal decay of ‘Mollar de Elche’ pomegranates during storage at 20 °C. Afterwards, selected antifungal ECs and commercial modified atmosphere packaging (MAP) films were assayed alone or in combination to control natural decay and preserve fruit quality of pomegranates stored at 5 °C for 4 months plus 1 week at 20 °C. Results showed that ECs amended with SB reduced pomegranate latent infections caused by Botrytis cinerea and wound diseases caused by Penicillium spp. Moreover, MAP technologies were confirmed as an efficient mean to preserve freshness, prevent fruit shriveling and rind browning, and reduce fungal decay, thus extending storage life of pomegranates. The combination HPMC-BW-SB + MAP was the most promising treatment as it reduced weight loss and decay, without negatively affecting the fruit physicochemical and sensory quality