ReDivia - Repositorio Digital de l'Instit Valencià d'Investigacions Agràries
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Rootstock-mediated variation in tomato vegetative growth under low potassium or phosphorous supplies
Get PDFGrafting provides a rapid and direct tool to transfer rootstock-mediated abiotic stress tolerance to commercial stress-sensitive cultivars. Nutrient deficiency is a widespread problem in some soils, inhibiting physiological processes and thus reducing crop yield. With the aim of selecting rootstocks conferring tolerance to potassium (K+) or phosphorous (P) deficits, a commercial tomato cultivar (‘Boludo F1’, ‘Monsanto’) was grafted onto 144 different rootstocks: six accessions from S. lycopersicum (‘Cerasiforme’) and S. pimpinellifolium, selected for drought tolerance (sourced from The World Vegetable Center, AVRDC); nine introgression lines from S. lycopersicum × S. pennellii and × S. habrochaites, selected for high root/shoot ratio, salinity and drought tolerances (sourced from The Tomato Genetics Resource Center, TGRC); and a population of 129 recombinant inbred lines (RILs) derived from a salt sensitive genotype of S. lycopersicum var. cerasiforme and a salt tolerant line from S. pimpinellifolium L. (sourced from Instituto Valenciano de Investigaciones Agrarias, IVIA). Plants were grown in semi-hydroponics or soil for 4-6 weeks (vegetative stage), under low K+ (1 mM) or low P (0.1 mM) supply. Shoot fresh weight was measured at the end of each experiment. There was a large rootstock-mediated variation in shoot biomass under each low nutrient condition. Some specific lines used as rootstocks performed better under low nutrient conditions than the self-grafted commercial cultivar ‘Boludo F1’. Furthermore, although some rootstocks seemed to perform well under different limiting conditions, no relation was found in shoot fresh weight for the two low nutrient conditions studied, suggesting that the mechanisms that control vegetative vigour seem to work differently depending on the specific nutrient deficiency. Results from this study will help in the future to identify genetic and physiological determinants that allow tomato roots to confer crop resistance to nutrient limitation as well as to improve fruit yield under individual and combined stresses
Effect of harvesting with a trunk shaker and an abscission chemical on fruit detachment and defoliation of citrus grown under Mediterranean conditions
Get PDFSpain ranks as the world's leading exporter of citrus for fresh consumption. Manual harvest accounts for 50% of the total production costs. Mechanical harvest would increase labor productivity and benefits of growers. Efficiency of these machines depends on the varieties and operating conditions. Use of abscission chemicals has been promoted to increase the detachment rate of fruit without affecting its quality. This work is aimed at studying whether the mechanical harvest and/or the application of an abscission agent affect the quality and quantity of harvested fruit and tree defoliation under the conditions of citrus cultivation in Spain. Trials were made in a completely randomized experimental design. From 2008 to 2011, different orchards of mandarin and orange trees were sprayed with different doses of ethephon as abscission agent and harvested with a trunk shaker. Harvest related variables (detachment percentage, defoliation and fruit without calyx) were measured. The percentage of fruit detached by the trunk shaker ranged between 70 and 85% and it did not depend on the orchard. The shaker produced minimal damage to the bark when gripped incorrectly. Increased doses of ethephon increased fruit detachment except in 'Clemenules' orchard, but also increased the fruit without calyx in 1-9%. Moreover, ethephon promoted significant defoliation. Neither gummosis nor death of branches was observed. This work demonstrates that mechanical harvesting with trunk shakers may be a feasible solution for citrus cultivated in Spain for fresh market. Use of ethephon could only be recommended for citrus destined to industry and only for certain varieties
Evaluation of a real-time PCR and a loop-mediated isothermal amplification for detection of 'Xanthomonas arboricola' pv. 'pruni' in plant tissue samples
No full textOperational capacity of real-time PCR and loop-mediated isothermal amplification (LAMP) diagnostic assays for detection of Xanthomonas arboricola pv. pruni was established in a ring-test involving four laboratories. Symptomatic and healthy almond leaf samples with two methods of sample preparation were analyzed. Kappa coefficient, sensitivity, specificity, likelihood ratios and post-test probability of detection were estimated to manage the risk associated with the use of the two methods
Resistance to pathogens in terpene down-regulated orange fruits inversely correlates with the accumulation of D-limonene in peel oil glands
Get PDFVolatile organic compounds (VOCs) are secondary metabolites acting as a language for the communication of plants with the environment. In orange fruits, the monoterpene D-limonene accumulates at very high levels in oil glands from the peel. Drastic down-regulation of D-limonene synthase gene expression in the peel of transgenic oranges harboring a D-limonene synthase transgene in antisense (AS) configuration altered the monoterpene profile in oil glands, mainly resulting in reduced accumulation of D-limonene. This led to fruit resistance against Penicillium digitatum (Pd), Xanthomonas citri subsp. citri (Xcc) and other specialized pathogens. Here, we analyze resistance to pathogens in independent AS and empty vector (EV) lines, which have low, medium or high D-limonene concentrations and show that the level of resistance is inversely related to the accumulation of D-limonene in orange peels, thus explaining the need of high D-limonene accumulation in mature oranges in nature for the efficient attraction of specialized microorganism frugivores
Acta Horticulturae
No full textThe control of Plum pox virus (PPV) and the management of sharka, require the use of reliable detection methods. Despite the considerable efforts made in many countries, PPV has been reported in most of the important Prunus growing countries worldwide. Moreover, it is occasionally intercepted in imported fruit-tree scion wood. Illegal trafficking and insufficiently controlled exchange of plant material are the main pathways of PPV spread over long distances. For decades, since the first description of sharka in 1932, there has been neither public awareness nor reliable methods applicable on a large-scale. ELISA technique reported for plant viruses in 1977 revolutionized PPV diagnosis to its advantage. Nevertheless, for more than a decade, ELISA techniques have been based exclusively on polyclonal antibodies that often present problems of specificity and other drawbacks. The production and use of specific monoclonal antibodies and later recombinant antibodies, constituted the second revolutionary fact in PPV detection and characterization. An example of their usefulness is that about ten million ELISAs for universal PPV detection have been performed using 5B-IVIA/AMR since 1994. The emergence of molecular amplification methods revolutionized PPV detection, as well. The EPPO (2004) protocol for PPV is based on validated techniques and reagents. Nowadays, real-time RT-PCR techniques constitute the gold standard for PPV detection. Different formats including direct systems for sample preparation are included in the current IPPC-FAO (2012) protocol for PPV. The choice of the most appropriate detection method is crucial and must be related to the final goal or purpose of the analysis. The combination of ELISA-5B based and spot real-time RT-PCR techniques reaches 100% accuracy for PPV detection. "Next generation sequencing" is a powerful strategy for PPV detection and characterization and could be a potential substitute for biological indexing
SNP markers applied to the characterization of Spanish tomato (Solanum lycopersicum L.) landraces
No full textThe variability present in 63 accessions of 14 Spanish tomato (Solanum lycopersicum L.) landraces has been studied using morpho-agronomical descriptors and molecular markers. For this purpose, a set of 32 polymorphic SNP has been specifically developed. The relation between Spanish landraces has been analysed using the information generated. The cluster analysis using SNP data showed a moderate correlation with morpho-agronomical data, which is rare considering the low level of genetic diversity found in tomato and that few genes control key traits in landrace recognition, as size, shape and external appearance. Compared with previous studies, the set of SNP markers used provides a reliable tool for the analysis of diversity, with high bootstrap values obtained in the cluster analysis. Nevertheless, it seems to exist a strong influence of the specific combination of populations of each landraces analysed, the marker type and set of markers on the analysis of genetic differentiation in tomato landraces. Specific combinations of SNP markers (from two to six markers per landrace) enabled the clear identification of most of the landraces evaluated. Its use would be a useful tool to control the commercial fraud typical of quality niche markets where high yielding modern varieties resembling traditional landraces are sold, taking advantage of the price premium of these materials. (C) 2015 Elsevier B.V. All rights reserved
A new method to analyse mosaics based on Symmetry Group theory applied to Islamic Geometric Patterns
Get PDFThis article presents a new method for analysing mosaics based on the mathematical principles of Symmetry Groups. This method has been developed to get the understanding present in patterns by extracting the objects that form them, their lattice, and the Wallpaper Group. The main novelty of this method resides in the creation of a higher level of knowledge based on objects, which makes it possible to classify the objects, to extract their main features (Point Group, principal axes, etc.), and the relationships between them. In order to validate the method, several tests were carried out on a set of Islamic Geometric Patterns from different sources, for which the Wallpaper Group has been successfully obtained in 85% of the cases. This method can be applied to any kind of pattern that presents a Wallpaper Group. Possible applications of this computational method include pattern classification, cataloguing of ceramic coatings, creating databases of decorative patterns, creating pattern designs, pattern comparison between different cultures, tile cataloguing, and so on
Male pronucleus formation after ICSI: effect of oocyte cysteine or sperm Triton X-100 treatments
Get PDFIn pigs, intracytoplasmic sperm injection (ICSI) efficiency is still poor. The inadequate decondensation of the sperm chromatin, its transformation into the male pronucleus (MPN) together with the subsequent inability to activate the oocyte, seem to be the main causes of the low ICSI efficiency. In order to improve the MPN formation we took two different approaches. On the one hand, the in vitro culture (IVC) medium postICSI was supplemented with 1.71mM cysteine (CYS). Alternatively, the sperm membrane was digested with Triton X-100 (TX) before ICSI, to improve the exposure of the sperm chromatin to the oocyte cytoplasm. After 6 h post-ICSI, the activation rate was significantly higher in TX group (70.0%) compared with CYS and control groups (42.2% and 48.9%, respectively; P < 0.05). However, no significant differences between the three groups were observed in terms of the number of pronuclei, 2PN (oocytes with 2 pronuclei and no visible sperm), and 1PN + sperm (oocytes with 1 pronucleus and one sperm head). At 22 h post-ICSI, the activation rates were similar in TX, CYS, and control groups (73.1, 78.9, and 75.7%, respectively). In addition, we did not observe significant differences between TX, CYS, and control groups for the number of pronuclei, 2PN (52.6, 56.7, and 50%, respectively) or 1PN + sperm (21.1, 33.3, and 32.1%, respectively). While no cleavage was observed in the CYS group, no significant differences in the cleavage rate were observed between control (21.3%) and TX (10.5%) groups. In summary, and under our conditions, neither CYS supplement, nor sperm TX pre-treatment were able to improve MPN formation at 6 and 22 h post-ICSI. However, the sperm TX pre-treatment improved oocyte activation at 6 h post-ICSI, although 22 h post-ICSI such a beneficial effect did not persist
Novel approaches to control browning of fresh-cut artichoke: Effect of a soy protein-based coating and modified atmosphere packaging
No full textA soy protein isolate (SPI):beeswax (BW) edible coating was optimized based on BW and L-cysteine (Cys) content to reduce the enzymatic browning of fresh-cut artichoke. The effect of this optimized coating, combined with different modified atmospheres (MA) to extend the shelf-life of cut artichokes, was studied during storage at 5 C. MAs were obtained by fluxing two gas mixtures (MA-A: 5 kPa O-2 + 15 kPa CO2; MAB: 80 kPa O-2) or by conventional passive MA (MA-P). Atmospheric conditions were used as the control. The use of 0.3 g/100 mL Cys combined with a SPI-BW edible coating (40 g/100 g BW, dry basis) helped control enzymatic browning and extended the commercial shelf-life of fresh-cut artichokes to 4 days without providing off-odors. The combination of the coating with MAs did not extend the shelf-life of artichoke slices, but helped maintain the product's antioxidant capacity as compared to the control packaging conditions. Given the high degree of perishability of untreated fresh-cut artichoke, a 4-day commercial period can be considered adequate to distribute sliced artichokes to local markets. However, more studies are required to further extend shelf-life. (C)2014 Elsevier B.V. All rights reserved
Material vegetal y mejora genética
Get PDFEl caqui (Diospyros kaki Thunb.) se originó en el este de Asia, donde existen
referencias de su cultivo en China que se remontan a varios siglos a. C. Desde
allí se introdujo en Japón en el siglo VII y ya en el siglo XIV se introduce
en Corea procedente de Japón. No existen registros de su cultivo en Europa
hasta el siglo XVII, cuando se expandió por toda la cuenca del Mediterráneo.
Las corrientes migratorias desde los países asiáticos a Norteamérica
introdujeron el cultivo del caqui en California (EE.UU.) y Brasil. El género
Diospyros cuenta con más de 400 especies, aunque la más conocida y
mayoritariamente cultivada es D. kaki, que cuenta con una amplia diversificación
varietal en China, Japón y Corea del Sur donde se han descrito más
de 2.000 variedades (Cho y Cho, 1965; Wang y col, 1997; Yamaday col,
2012). La especie D. virginiana L. es originaria de América del Norte y fue
descrita por primera vez en el estado de Virginia (EE.UU.) de donde toma
el nombre (Yonemori y col, 2000). Aunque esta especie produce frutos
comestibles, su uso está más extendido como portainjertos