ReDivia - Repositorio Digital de l'Instit Valencià d'Investigacions Agràries
Not a member yet
2747 research outputs found
Sort by
Soil management in semi-arid vineyards: Combined effects of organic mulching and no-tillage under different water regimes
Get PDFOptimizing water use in vineyards is crucial for ensuring the sustainability of viticulture in semi-arid regions, and this may be achieved by minimizing direct water evaporation from the soil through the use of mulching. In this context, the current study aimed at assessing the combined effects of the vine-row application of an organic mulch (vine prunings) and no-tillage under two water regimes on soil properties, plant water and nutritional status, yield and must composition of grapevine (Vitis vinifera L.) cv. Bobal grown under semi-arid conditions. For this purpose, a field experiment in a split-plot design was carried out for three years (2016–2018) in a mature Bobal vineyard located in Eastern Spain. Two soil management strategies (tillage and organic mulching with no-tillage) were assessed under two water regimes (rainfed and deficit drip irrigation) with four replications per combination. Vine responses were determined by measuring midday stem water potential, leaf nutrient concentrations, pruning weight, yield components and grape composition. Soil properties were assessed at the end of the experiment. Mulching and no-tillage positively affected vine water status under both water regimes, resulting in reductions in grape phenolic composition. Interactive effects of both water regime and soil management on water use efficiency were found. Regardless of soil management practice, irrigation increased yield and pruning weight when compared to rainfed conditions. Soil management had slight effects on vine nutritional status. At the end of the experiment, soil compaction increased and infiltration decreased as a consequence of mulching and no-tillage. Organic mulch and no-tillage improved vine water status, however, considering the final soil surface compaction and low water infiltration rate, longer-term studies are necessary to assess the sustainability of combining both practices
The pest kill rate of thirteen natural enemies as aggregate evaluation criterion of their biological control potential of Tuta absoluta
Get PDFEcologists study how populations are regulated, while scientists studying biological pest control apply population regulation processes to reduce numbers of harmful organisms: an organism (a natural enemy) is used to reduce the population density of another organism (a pest). Finding an effective biological control agent among the tens to hundreds of natural enemies of a pest is a daunting task. Evaluation criteria help in a first selection to remove clearly ineffective or risky species from the list of candidates. Next, we propose to use an aggregate evaluation criterion, the pest kill rate, to compare the pest population reduction capacity of species not eliminated during the first selection. The pest kill rate is the average daily lifetime killing of the pest by the natural enemy under consideration. Pest kill rates of six species of predators and seven species of parasitoids of Tuta absoluta were calculated and compared. Several natural enemies had pest kill rates that were too low to be able to theoretically reduce the pest population below crop damaging densities. Other species showed a high pest reduction capacity and their potential for practical application can now be tested under commercial crop production conditions
Influence of farm management on the dynamics of Salmonella enterica serovar Infantis shedding and antibiotic resistance during the growing period of broiler chickens
Get PDFBackground: Salmonella enterica serovar Infantis is a zoonotic pathogen isolated in broilers causing great economic losses in the European poultry sector. It is demonstrated that an investment in management measures at farm level could directly affect the control of food chain microorganisms. The aim of this study was to investigate the development of S. Infantis antimicrobial resistance (AMR) patterns during the growing period, according to flock density and ventilation management, without antibiotic administration. Methods: The experiment was performed in two identical poultry houses, evaluating commercial and optimal farm conditions. At 24 h of rearing, 20% of the animals were orally infected with a S. Infantis strain susceptible to all the antibiotics tested. To study Salmonella shedding, faeces samples from each experimental group were taken weekly and analysed as per ISO/TS 6579–2:2017. Antibiotic susceptibility was assessed according to Decision 2013/653. Results: Salmonella shedding showed that the lowest counts were observed in the first week post-infection and highest at slaughter day for both groups. Moreover, 100% of the isolates were multi-resistant. Conclusion: The acquisition of AMR by S. Infantis starts at the onset of the production cycle and is maintained until the end, demonstrating the importance of transmission of AMR in zoonotic bacteria at farm level
Remating in Ceratitis capitata sterile males: Implications in sterile insect technique programmes
Get PDFSterile insect technique (SIT) is used, among other biological control tools, as a sustainable measure for the management of Ceratitis capitata Wiedemann (Diptera: Tephritidae) in many agricultural regions where this pest can trigger severe economic impacts. The tendency of wild females to remate multiple times has been deeply studied; it has been a common point of controversy when evaluating SIT programmes. Nevertheless, the remating potential of the released sterile males remains unknown. Here, under laboratory conditions, the remating capability of mass-reared sterile males was determined. Wild-type virgin females were offered to sterile males (Vienna-8 strain), which had the opportunity to mate up to four consecutive times. The remating assays were carried out at 24 hr, 48 hr, 4 days and 7 days after the first mating. At the end of each tested time period, males were divided according to their mating response, mated or unmated, and subsequently reused for the next round of mating assays. The frequency of successful remating in each tested time period was obtained. Insemination was confirmed by determining the sperm transfer in mated female spermathecae by quantitative real-time PCR. Our results demonstrate that 73% of the mass-reared sterile males were able to remate 24 hr after the first mating, 55% of which remated again the day after. Close to 25% of the V8 sterile males tended to copulate in all of the four mating opportunities. The qPCR analysis of the spermathecae contents verified an effective transfer of V8 sperm to wild females with every mating; 99% of copulations resulted in sperm transfer. These findings shed light on the remating potential of V8 sterile males, an aspect until now underestimated in many SIT programmes
Characterization of Spanish Olive Virome by High Throughput Sequencing Opens New Insights and Uncertainties
Get PDFThe use of high throughput sequencing (HTS) for the analysis of Spanish olive trees showing leaf yellowing discoloration, defoliation, and/or decline has provided new insights into the olive viruses present in Spain and has opened discussions about the pros and cons of these technologies for diagnostic purposes. In this study, we report for the first time in Spanish orchards the presence of olive leaf yellowing-associated virus (OLYaV), for which the second full coding sequence has been determined. This virus has also been detected in a putative vector, the psyllid Euphyllura olivina. In addition, the presence in Spain of Olea europaea geminivirus (OEGV), recently reported in Italy, has been confirmed, and the full-length sequence of two isolates was obtained by HTS and Sanger sequencing. These results, as well as the detection of other viral sequences related to olive latent virus 3 (OLV-3) and olive viral satellite RNA, raises questions on the biological significance of the findings, about the requirement of standardization on the interpretation of HTS results, and the necessity of additional tests to confirm the relevance of the HTS detection of viral sequence
Screening of ‘King’ Mandarin Hybrids as Tolerant Citrus Rootstocks to Flooding Stress
Get PDFThis work compares the tolerance to long-term anoxia conditions (35 days) of five new citrus ‘King’ mandarin (Citrus nobilis L. Lour) Poncirus trifoliata ((L.) Raf.) hybrids (named 0501XX) and Carrizo citrange (CC, Citrus sinensis (L.) Osb. Poncirus trifoliata (L.) Raf.), the widely used citrus rootstock in Spain. Growth parameters, chlorophyll concentration, gas exchange and fluorescence
parameters, water relations in leaves, abscisic acid (ABA) concentration, and PIP1 and PIP2 gene expressions were assessed. With a waterlogging treatment, the root system biomass of most hybrids went down, and the chlorophyll a and b concentrations substantially dropped. The net CO2 assimilation rates (An) and stomatal conductance (gs) lowered significantly due to flooding, and the transpiration rate (E) closely paralleled the changes in gs. The leaf water and osmotic potentials significantly increased in most 0501 hybrids. As a trend, flooding stress lowered the ABA concentration in roots from most hybrids, but increased in the leaves of CC, 05019 and 050110. Under the control treatment (Ct) conditions, most 0501 hybrids showed higher PIP1 and PIP2 expressions than the control rootstock CC, but were impaired due to the flooding conditions in 05019 and 050110. From this study, we conclude that 0501 genotypes develop some adaptive responses in plants against flooding stress such as (1) stomata closure to prevent water loss likely mediated by ABA levels, and (2) enhanced water and osmotic potentials and the downregulation of those genes regulating aquaporin channels to maintain water relations in plants. Although these traits seemed especially relevant in hybrids 050110 and 050125, further experiments must be done to determine their behavior under field conditions, particularly their influence on commercial varieties and their suitability as flooding-tolerant hybrids for replacing CC, one of the main genotypes that is widely used as a citrus rootstock in Spain, under these condition
Retos para la detección de bacterias fitopatógenas mediante PCR: el caso de 'Candidatus Liberibacter' spp. asociados al HLB
Get PDFEl HLB es la enfermedad más devastadora de los cítricos que se conoce hoy en día. Se asocia a tres especies bacterianas del género Liberibacter: `Candidatus Liberibacter asiaticus´, `Ca. L. africanus´ y `Ca. L. americanus´. Estas bacterias son transmitidas por insectos vectores de la familia Psyllidae, y no se han podido cultivar hasta el momento en el laboratorio, lo que dificulta en gran medida su estudio y control. La prevención de la diseminación de estas tres especies y de su entrada en áreas libres de la enfermedad, como el continente europeo y, en particular, la cuenca mediterránea, requiere el uso de técnicas de detección específicas y sensibles
Fases finales del crecimiento y características metabólicas en bovinos de raza Wagyu y cruzados con Angus (Wangus) en un sistema de producción español
Get PDFLa raza wagyu (WY) se caracteriza por dar lugar a una carne con un alto grado de infiltración, de alta calidad (Shahrai et al. 2020) y de alto interés en el mercado mundial. Carne más engrasada que la tradicional en bovino también se origina en animales de raza Angus, aunque ambas razas presentan ritmos de crecimientos y calidad de la carne diferenciadas (Radunz et al. 2009; Shahrai et al. 2020). El cruce de la raza Angus con Wagyu (wangus, WN) es, por lo tanto, de interés productivo. Sin embargo, hay
pocos estudios sobre las características productivas de animales WY y WN en sistemas de producción españoles. Por tanto, el objetivo de este estudio fue evaluar el crecimiento y las características metabólicas de WY y WN en la fase final del engorde
Efecto del número de tomas y el gluconato cálcico en el comportamiento de terneras de recría. Resultados preliminares
Get PDFEn producción ganadera, uno de los mayores retos es optimizar el bienestar animal. En el caso de las terneras, en las primeras etapas de su vida, son muy susceptibles al estrés. Además, un correcto crecimiento durante estas etapas tiene un gran impacto en el desarrollo y capacidad productiva en el futuro (Kaske et al., 2010). Hay muchos factores de estrés, pero destaca fundamentalmente el programa de alimentación en la lactancia. En este caso, lo más importante es reducir lo máximo posible la
sensación de hambre. Otro factor a tener en cuenta es la socialización entre las terneras, ya que a mayor socialización, presentan menor estrés (Hulbert y Moisá, 2016). Así, el objetivo general es desarrollar nuevas estrategias de alimentación y socialización en la fase peri-destete de terneras con aptitud lechera para optimizar su bienestar animal y futura productividad
Physiological and antioxidant mechamisms to overcome water stress on grafted peppers
Get PDFAmong abiotic stresses affecting crops, water scarcity rises as a major problem in many parts of the world, causing important losses in crop yield and productivity every year (Ashraf, 2010; Farooq et al., 2009; Mastrangelo et al., 2012). Grafting emerges as a sustainable technique that can be used to face this threat, particularly in Solanaceae species, usually cultivated in areas suffering from water starvation (Fullana-Pericàs et al., 2020; Kumar et al., 2017; Rouphael et al., 2018). Little has been published about the processes underlying grafted plants tolerance to water stress, especially in pepper plants. This work aimed to unravel several physiological and antioxidant mechanisms responsible for tolerance in pepper grafted plants under water stress