ReDivia - Repositorio Digital de l'Instit Valencià d'Investigacions Agràries
Not a member yet
2747 research outputs found
Sort by
Factors influencing the efficacy of two organophosphate insecticides in controlling California red scale, Aonidiella aurantii (Maskell). A basis for reducing spray application volume in Mediterranean conditions
Get PDFBackground: Because society is seeking ways to lessen the environmental impact of agricultural activity, dose adjustment has become a key issue in current plant protection treatments with high spray application volumes, such as on citrus plants. This work investigates, in field conditions, the factors affecting the efficacy of organophosphate insecticides against California red scale (CRS), Aonidiella aurantii (Maskell), when the delivery rate is decreased. Insecticide rate changes were induced by modifying the spray application volumes of two commercial organophosphate pesticides based on chlorpyrifos and chlorpyrifos-methyl. Results: Results showed that, with increase in the spray volume, the coverage and the uniformity of deposition on the canopy increased, but final infestation depended neither on the spray application volume nor on the coverage. Furthermore, final infestation significantly depended on the pest pressure in the plot and the spray volume applied per unit volume of canopy (L m(-3) canopy). Moreover, it was found that the final infestation was influenced by the efficiency of deposition in the applications that were carried out against the second-generation of CRS. Conclusion: Because the spray application volume did not affect the final infestation, this research introduces the possibility that reducing the doses of current citrus organophosphate treatments may still allow effective plant protection in Mediterranean conditions
Extending the shelf life of fresh-cut eggplant with a soy protein-cysteine based edible coating and modified atmosphere packaging
No full textThe effect of a soy protein-based edible coating with antioxidant activity, and conventional and super-atmospheric modified atmosphere (MA) packaging, on the quality of fresh-cut 'Telma' eggplants, was evaluated during storage. In a first experiment, eggplant pieces were dipped in either a coating composed of soy protein isolate (SPI) and 0.5% cysteine (Cys), or water as an uncoated control. Samples were packed in trays under atmospheric conditions to reach a passive MA (MA-P) or two gas mixtures (MA-A: 15 kPa CO2 + 5 kPa O-2; MA-B: 80 kPa O-2) and were stored at 5 degrees C. Atmospheric conditions were used as the control conditions (Control). The coated samples packed under MA-B and Control conditions resulted in the highest whiteness index (WI) values during storage, whereas MA-A did not improve the shelf-life of minimally processed eggplants and had the lowest WI values. The MA-Band atmospheric control conditions helped to maintain firmness, whereas the coating helped to maintain the weight loss under MA-A and MA-B. The maximum commercial shelf-life was reached on day 6 for the coated samples packed under atmospheric conditions. In a second experiment, the commercial shelf-life of fresh-cut eggplants was extended to 8 and 9 storage days by increasing the Cys content in the edible coating from 0.5 to 1% under MA-B and Control storage conditions, respectively. (C) 2014 Elsevier B.V. All rights reserved
Crop load regulation and irrigation strategies to accelerate the recovery of previously water-stressed Japanese plum trees
No full textRegulated deficit irrigation (RDI) has been proven as a useful irrigation strategy in a wide range of fruit crops to deal with water scarcity. However, long-term RDI techniques in developing orchards can reduce tree growth resulting in a loss of tree yield capacity. Strategies that could be used to quickly recover trees from the possible carry-over effects of long-term deficit irrigation are then of physiological and commercial interest. Tree crop load is a determinant factor of the carbohydrates partitioning between fruit and vegetative sinks, being fruit sink strength higher than that of vegetative organs. The working hypothesis of this study was that tree crop load reduction could be employed to alleviate the detrimental effects that long lasting RDI strategies have on tree growth. The recovery of a young plum Japanese orchard (Prunus salicina, cv. 'Black Gold') after seven seasons under RDI was studied by testing combinations of two crop load levels (medium and low), two drip irrigation regimes [100 and 133% of crop evapotranspiration (ETc)] and two different number of emitters per tree (six and eight). Results showed that treatments applied led former RDI treatment trees to significantly reduce their differences in tree shaded area and particularly in trunk perimeter with respect to the control treatment trees. After two seasons of treatments, differences in yield, economic return and number of fruit per tree were exclusively due to the crop load levels imposed and not to a smaller size of former RDI treatment trees. Trees watered at 133% ETc and thinned at low crop load, which underwent a very severe RDI strategy previous to this experiment, were the trees that showed the greatest recovery in tree size. In this treatment, the lower competition between fruit and vegetative growth and the increase in the soil wetting area by using a higher number of emitters per tree, probably favored root growth significantly increasing tree growth with respect to the other treatments. Overall, this work shows that crop load regulation is a useful tool to quickly recover plum trees from the detrimental effects of long-term deficit irrigation. (C) 2013 Elsevier B.V. All rights reserved
Reducing the time rabbit sperm are held at 5 degrees C negatively affects their fertilizing ability after cryopreservation
No full textCooling sperm to and equilibrating the sperm at 5 degrees C require the most time in any sperm cryopreservation protocol. Reducing the time required for these phases would simplify sperm freezing protocols and allow greater number of ejaculates to be processed and frozen in a given time. This study determined how holding rabbit sperm at 5 degrees C for different lengths of time (0, 10, 15, 20, 30, or 45 minutes) affected the quality of rabbit sperm, measured by in vitro assays, and if reducing the cooling time to only 10 minutes affected the fertilizing ability of the sperm. Reducing the time sperm were held at 5 degrees C to 10 minutes did not affect the in vitro quality of the sperm (percent motile and with intact plasma membranes), although eliminating the cooling phase completely (directly freezing the sperm from room temperature) decreased in vitro assessed sperm quality (P < 0.01). However, reducing the time sperm were held at 5 degrees C, from 45 to 10 minutes, negatively affected the fertilizing ability of sperm in vivo (P < 0.05). In conclusion, completely eliminating cooling rabbit sperm to 5 degrees C before freezing is detrimental for rabbit sperm cryosurvival, and although shortening the time sperm are held at 5 degrees C to 10 minutes does not reduce in vitro sperm quality, it does reduce the fertility of rabbit sperm. Therefore, the length of time rabbit sperm equilibrate at 5 degrees C is crucial to the fertilizing ability of rabbit sperm and must be longer than 10 minutes. Currently, it is not known if holding rabbit sperm at 5 degrees C for less than 45 minutes will affect sperm fertilizing ability. (C) 2014 Elsevier Inc. All rights reserved
Respuesta agronómica de la variedad "Moscatel de Alejandría" al riego en clima mediterráneo
Get PDFCuatro diferentes estrategias de riego se estudiaron durante 2012 y 2013 en
un viñedo adulto de uva blanca de la variedad Moscatel de Alejandría/161-49C
regado por goteo en Villamarchante (Valencia): Testigo, cepas regadas al 100% de
la evapotranspiración del cultivo (ETc) desde que el potencial hídrico de tallo (tallo)
alcanzó -0.65 MPa hasta final de campaña; Riego Deficitario Sostenido (RDS),
regado al 50% del Testigo durante toda la campaña; Déficit pre-envero (DPre),
retraso del inicio del riego durante la primavera hasta alcanzar -1.0 MPa de tallo;
Déficit post-envero (DPost), regado como el Testigo hasta envero, posteriormente al
25% de la ETc hasta vendimia. La producción se redujo en el DPre en ambas
campañas y en todos los tratamientos deficitarios en 2013 respecto del Testigo (por
disminución de la fertilidad y del peso de racimo). Únicamente el DPre en 2012
redujo el peso de baya (-14%) que fue acompañado de un incremento en los sólidos
solubles totales. No obstante, las diferencias en la composición química de la uva
entre tratamientos fue mínima, con ligera tendencia a aumento de la acidez titulable
al hacerlo el volumen de riego. El crecimiento vegetativo fue significativamente
mayor en el Testigo que en el resto de tratamientos (incrementos significativos del
área foliar y del peso de poda). Por todo ello, bajo las condiciones de escasez de
recursos hídricos de la zona de ensayo, la estrategia de riego más conveniente ha sido
el RDS, pues permite incrementar significativamente la eficiencia del uso del agua
manteniendo el 87% del potencial productivo de la variedad Moscatel de Alejandría
Actas de Horticultura
Get PDFLos virus son organismos muy sencillos que se multiplican dentro de las células vegetales y aunque no suelen provocar la muerte de la planta, inducen síntomas que disminuyen el rendimiento y la calidad del cultivo reduciendo su valor comercial. Sin embargo, algunos síntomas de origen vírico tienen cierto valor ornamental y son explotados con fines comerciales, como ocurre con el virus del variegado del tulipán (Tulip breaking virus, TBV). Los síntomas más característicos que inducen los virus son enanismo, clorosis, necrosis y deformación foliar, variaciones de color de la hoja y en la flor en forma de mosaicos, moteados, rayas o manchas anulares. La mayoría de los virus se transmiten mediante organismos vectores que se alimentan de la planta: insectos, ácaros, hongos y nematodos; otros se dispersan por contacto físico y por las herramientas agrícolas (transmisión mecánica) y unos pocos se propagan por semilla. Dentro de los virus con más impacto en los cultivos ornamentales están el virus del mosaico del pepino (Cucumber mosaic virus, CMV), el virus del bronceado del tomate (Tomato spotted wilt virus, TSWV), el virus del mosaico del tabaco (Tobacco mosaic virus, TMV) y el virus del rayado del tabaco (Tobacco streak virus, TSV), que también causan graves daños en otros cultivos. El control de las enfermedades producidas por los virus se basa en la aplicación de medidas preventivas como el uso de material propagativo libre de virus mediante certificación de semillas o plántulas en vivero, eliminación de plantas infectadas en el cultivo y durante el proceso de comercialización, control de los vectores (insectos, hongos, nemátodos), desinfección de las herramientas, limpieza de malas hierbas (reservorios de virus) dentro y fuera del invernadero, etc. Para ello es necesario un monitoreo rutinario mediante la observación visual de síntomas y el uso de técnicas para el diagnóstico rápido, sensible y fiable tanto de los virus más importantes como de los de nueva implantación o virus emergentes
Feeding programmes based on highly-digestible fibre weaning diets: Effects on health, growth performance and carcass and meat quality in rabbits
Get PDFThe effect of three different dietary programmes on health, growth performance and carcass and meat quality in young rabbits weaned at 28 d was studied using a diet (F) rich in highly-digestible fibre, from 17 to 63 d of age (group FF); using diet F from 17 to 42 d followed by a diet poor in highly-digestible fibre and rich in starch and fat (S) until 63 d (group FS); and using a standard diet C with intermediate highly-digestible fibre and starch content, containing 100 ppm of zinc-bacitracin, from 17 to 63 d (group CC). A highly-digestible fibre diet could be useful to reduce the incidence of digestive disorders. However, it decreased slaughter weight (2294 g in FF vs. 2406 g in CC; P<0.05) and carcass and meat traits, e.g. dressing out percentage (55.4% in FF vs. 56.7% in CC; P<0.05), meat to bone ratio (5.73 in FF vs. 5.94 in CC; P<0.05) and hind leg fat content (3.81% in FF vs. 4.71% in CC; P<0.05) at 63 d of age. Switching to a high starch and fat diet at late fattening improved chilled carcass weight at 63 d of age (1339 g in FS vs. 1263 g in FF; P<0.05) mainly through the promotion of liver development (7.53% in group FS vs. 6.47% in group FF; P<0.05) and fat deposition (3.89% in FS vs. 2.63% in FF; P<0.05), and increased hind leg fat content (+1.2 points of fat percentage; P<0.05). However, this switch increased health risk (35.1% in FS vs. 17.6% in FF; P<0.05)
Metabolic engineering of beta-carotene in orange fruit increases its in vivo antioxidant properties
No full textOrange is a major crop and an important source of health-promoting bioactive compounds. Increasing the levels of specific antioxidants in orange fruit through metabolic engineering could strengthen the fruit's health benefits. In this work, we have afforded enhancing the -carotene content of orange fruit through blocking by RNA interference the expression of an endogenous -carotene hydroxylase gene (Cs-CHX) that is involved in the conversion of -carotene into xanthophylls. Additionally, we have simultaneously overexpressed a key regulator gene of flowering transition, the FLOWERING LOCUS T from sweet orange (CsFT), in the transgenic juvenile plants, which allowed us to obtain fruit in an extremely short period of time. Silencing the Cs-CHX gene resulted in oranges with a deep yellow (golden') phenotype and significant increases (up to 36-fold) in -carotene content in the pulp. The capacity of -carotene-enriched oranges for protection against oxidative stress in vivo was assessed using Caenorhabditis elegans as experimental animal model. Golden oranges induced a 20% higher antioxidant effect than the isogenic control. This is the first example of the successful metabolic engineering of the -carotene content (or the content of any other phytonutrient) in oranges and demonstrates the potential of genetic engineering for the nutritional enhancement of fruit tree crops
Two potato (Solanum tuberosum) varieties differ in drought tolerance due to differences in root growth at depth
No full textTo test the hypothesis that root growth at depth is a key trait explaining some genotypic differences in drought tolerance in potato (Solanum tuberosum L.), two varieties (Horizon and Maris Piper) differing in drought tolerance were subjected to different irrigation regimes in pots in a glasshouse and in the field under a polytunnel. In the glasshouse, both cultivars showed similar gas exchange, leaf water potential, leaf xylem ABA concentration and shoot biomass independently of whether plants were grown under well watered or water deficit conditions. Under well watered conditions, root growth was three-fold higher in Horizon compared with Maris Piper, 3 weeks after emergence. Water deficit reduced this difference. In the polytunnel, applying 60% or less irrigation volume compared with full irrigation significantly decreased tuber yield in Maris Piper but not in Horizon. This was coincident with the higher root density of Horizon in deep soil layers (>40 cm), where water content was stable. The results suggest that early vigorous root proliferation may be a useful selection trait for maintaining yield of potato under restricted irrigation or rainfall, because it rapidly secures access to water stored in deep soil layers. Although selecting for vigorous root growth may assist phenotyping screening for drought tolerance, these varieties may require particular environmental or cultural conditions to express root vigour, such as sufficiently deep soils or sufficient water shortly after emergence
Direct Comparison of the Effects of Slow Freezing and Vitrification on Late Blastocyst Gene Expression, Development, Implantation and Offspring of Rabbit Morulae
No full textContents This study aimed to assess the effect of different cryopreservation procedures (slow freezing vs vitrification) on the gene expression in pre-implantation embryos and its implication in post-implantation embryo losses in rabbit. For this purpose, rabbit morulae were recovered at Day 3 of development, frozen or vitrified and transferred to recipients. Then, embryos were recovered on Day 3 post-transfer (Day 6 of development) or kept until the end of gestation. Apart from the gene expression analysis at Day 6, we also studied the pre-implantatory and foetal development ability of both cryopreserved embryo types by evaluating late blastocyst development at Day 6, embryo implantation at Day 11 post-transfer (Day 14 of development) and birth rate. We reported that slow freezing and vitrification have similar effects on embryo developmental ability till Day 6, but the distribution of losses changes during implantation and further development. These similarities at Day 6 of development were also reflected in gene expression patterns, and transcriptome analysis showed no differences between frozen and vitrified embryos. Our results confirm that vitrification provides better implantation and birth rates than slow freezing for rabbit embryos. As both the techniques are commonly used in human assisted reproduction, further experiments must be conducted to clarify the causes that may hinder foetal development and their impact on adulthood