ReDivia - Repositorio Digital de l'Instit Valencià d'Investigacions Agràries
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El cultivo del caqui
No full textEl caqui no había presentado hasta la fecha demasiados problemas causados por fitófagos plaga. Sin embargo, durante los últimos años se han detectado problemas importantes con algunos fitófagos que han alcanzado la categoría de plaga. Entre ellos destacan las cochinillas algodonosas o cotonets (Planococcus citri, Pseudococcus longispinus, Pseudoccocus viburni y/o Delottococcus aberiae) y la barreneta (Cryptoblabes gnidiella). Los cotonets provocan la maduración prematura y caída de los frutos, así como la proliferación de otras plagas como la barreneta. En el caqui podemos encontrar también otras plagas como la mosca de la fruta (Ceratitis capitata), que requiere una atención especial para su control durante el período de susceptibilidad del fruto. A pesar que la suelta de machos estériles y la colocación de trampas quimioesterilizantes o de captura masiva han conseguido reducir la población de mosca de la fruta a niveles inferiores a los de hace unos años, en ocasiones es necesario realizar tratamientos cebo a base de proteínas hidrolizadas. De forma anecdótica pueden detectarse algunas cochinillas como Saissetia oleae y Parthenolecanium corni o larvas de algunos coleópteros que provocan daños en madera. En este capítulo se recoge la información necesaria para identificar las principales plagas que atacan al caqui y mejorar su gestión integrada
Citrus Viroids: Symptom Expression and Performance of Washington Navel Sweet Orange Trees Grafted on Carrizo Citrange
No full textCitrus are natural hosts of several viroid species. Citrus exocortis viroid (CEVd) and Hop stunt viroid (HSVd) are the causal agents of two well-known diseases of citrus, exocortis and cachexia. Other viroids have been found to induce specific symptoms and different degrees of stunting in trees grafted on trifoliate orange and trifoliate orange hybrids. A field assay was initiated in 1989 to establish the effect of CEVd, HSVd, Citrus bent leaf viroid (CBLVd), Citrus dwarfing viroid (CDVd), and Citrus bark cracking viroid (CBCVd) on Washington navel sweet orange trees grafted on Canizo citrange rootstock. Here we report the effect of viroid infection on symptom expression, tree size, fruit production and quality evaluated from 2004 to 2007. Vegetative growth was affected by viroid infection with height and canopy volume being reduced. No bark scaling symptoms were observed in CEVd-infected trees albeit they presented lesions and blisters in the roots. Bark cracking symptoms were consistently observed in CBCVd-infected trees that were smaller with enhanced productivity and fruit size. No major effects were found as a result of infection with CBLVd, HSVd, or CDVd. The quality of the fruits was not affected by viroid infection, except for the low diameter of the fruits harvested from HSVd-infected trees. An interesting effect was identified in terms of tree productivity increase (yield/canopy volume) as a result of infection with CEVd, CDVd, and especially CBCVd
Técnicas de cultivo al aire libre y sandía sin pepitas
Get PDFCon riego a pie es fundamental una buena nivelación. En ese caso, antes de la preparación de los surcos de riego debe pasarse una niveladora láser. La raíz de la sandía puede alcanzar bastante profundidad, por lo que la preparación del suelo debe comprender algunas labores que remuevan horizontes profundos. Es bastante usual el empleo de subsolador, seguido de pases
de grada o fresadora. Es conveniente iniciar cuanto antes la preparación del terreno, si la situación del cultivo en la rotación lo permite y tratar de destruir la mayor cantidad posible de malas hierbas, mediante labores superficiales continuadas. Cuando el riego es superficial, la última labor es para preparar el riego y la plantación. Se pueden hacer surcos, coincidiendo con las líneas de plantación, cuando los primeros riegos se han de dar con estos surcos o pequeños caballones, en cuya cresta se planta, regándose por inundación todo el terreno
Description of the airflow produced by an air-assisted sprayer during pesticide applications to citrus
Get PDFAtmospheric drift of plant protection products is considered a major source of air pollution during pesticide applications. Citrus protection against pests and diseases usually requires application of these products using air-blast sprayers. Many authors have emphasized the influence of vegetation on the risk of spray drift. The aim of this work was to describe in detail how the airflow from an air-blast sprayer behaves when it reaches citrus trees and, in particular, the effect that the tree canopy has on this flow. Tests were conducted at a commercial citrus orchard with conventional machinery, placed parallel to a row of trees. Air velocity and direction was measured using a 3D ultrasonic anemometer in 225 points situated in three parallel planes perpendicular to the equipment. The stability of the airflow at each measuring point was studied and the mean velocities were graphically represented. Two vortexes, one behind the canopy, and another over the tree, have been deducted and never been reported before. Both may have an important influence on the trajectories of the sprayed droplets and, as a consequence, on the way in which plant protection products are diffused into the atmosphere. Observed turbulence intensities were higher than in similar experiments conducted in other tree crops, which may be attributable to the higher air volume generated by the machinery used for citrus protection and to the higher foliage density of citrus orchards
Acta Horticulturae
No full textRootstock provides better adaptation to biotic and abiotic constraints. Poncirus and its hybrids are widely used since they are tolerant to Citrus tristeza virus. However, when grafted, most of them are considered to be sensitive to salinity and water deficit. Diversity does exist within the Poncirus trifoliata species, but little is known regarding the behaviour variability of genotypes to abiotic constraints. The citrus diversity of 72 P. trifoliata genotypes was investigated using SSR markers. Two major genetic groups were clearly identified. Five genotypes, belonging to each genetic group, were then selected to investigate their properties of tolerance to water deficit. Water deficit was applied by withdrawing irrigation for 4 weeks. Physiological parameters such as leaf stomatal conductance and gravitational water quantity were estimated. Among genotypes, we observed that some genotypes such as 'Rubidoux' were clearly more tolerant to water deficit than others such as 'Pomeroy'. Interestingly, the genotypes that were sensitive belonged to one genetic group and the less tolerant ones belonged to the other group. Therefore, our results suggest that among the Poncirus genus, it is possible to select genotypes as parent in breeding programs, which are better tolerant to water deficit
Chemical Engineering Transactions
Get PDFVery nutritional and healthy, dried figs constitute an appreciated food for local populations of the Mediterranean area. However, the incidence of mycotoxins in this product, mainly attributed to traditional and poor agricultural practices, has been widely demonstrated and may develop quickly if storage conditions are not suitable, exceeding maximum safety thresholds set by European Union regulations. Mycotoxin identification is currently achieved by means of destructive methods that need sample preparation, and moreover are expensive and time consuming. Early and reliable detection techniques are required to prevent high risks for humans. Hyperspectral imaging is currently used for quality evaluation and safety inspection of agricultural products and food. It has not been used for the detection of dried fig contamination but could be a promising tool to determine the best spectral bands that permit contaminated fruit to be identified and eliminated, especially when applied to postharvest automated processes. In this context, the present work deals with preliminary trials on the ability of hyperspectral imaging to identify contaminations with aflatoxins and ochratoxin A on dried fig of Cosenza (PDO, Protected Designation of Origin) fruit by analyzing UV-induced fluorescence. Artificially contaminated figs did not show any fluorescence while decayed figs emitted fluorescence between 450 nm and 490 nm. The obtained results highlighted important aspects to be considered in order to improve the applied methodology and carry out further researches on the present theme
Genetic diversity and phylogeographic structure of sixteen Mediterranean chicken breeds assessed with microsatellites and mitochondrial DNA
No full textThe genetic diversities and relationships among 16 local breeds of chicken originating from five countries (Italy, Spain, Serbia, Albania and Republic of Malta) within the Mediterranean basin were assessed by sequencing part of the mitochondrial DNA (mtDNA) D-loop region and by genotyping individuals at 27 autosomal microsatellite loci. The aim was to study the microevolution of chicken on the northern shores of the Mediterranean and to determine their present genetic status. A 506 bp fragment of the mtDNA control region was sequenced in 160 individual DNA samples. The mtDNA sequence polymorphisms nomenclature that is normally used in these studies suggests that the Mediterranean chicken breeds under investigation are related to haplogroup E. A total of 465 blood samples were collected and utilised for microsatellite analysis. Six breeds (Ancona, Livornese Bianca-Italy; Pita Pinta Asturiana, Gallina de Sobrarbe-Spain; Albanian population-Albania; and the Maltese Black Malta) showed significant high levels of inbreeding. About 22% of the total genetic variation observed was due to variability between populations. STRUCTURE analysis confirmed the breed variability result (F-ST=0.22) also observed in the Neighbor-Net dendrogram. These results strongly allude that the 16 Mediterranean chicken breeds studied originated from three distinct maternal lineages and retain moderate levels of autosomal genetic diversity. (C) 2015 Elsevier B.V. All rights reserved
Effects of Preflowering Leaf Removal on Phenolic Composition of Tempranillo in the Semiarid Terroir of Western Spain
No full textThe effects of preflowering defoliation on the qualitative and quantitative composition of phenolic compounds in the grape skins of Tempranillo grapevines grown in a semiarid terroir of western Spain, Badajoz, were determined. Control vines were compared with defoliation carried out before flowering (ED) in 2009 and 2010. Forty-two phenolic compounds were identified and quantified in the grape skins, including anthocyanins, flavonols, flavanols (cathechin and epi-cathechin and the flavanol dimmers B1, B2, and B3), and hydroxycinnamic acids, as both simple and conjugated molecules. ED did not significantly alter the concentration of total anthocyanidins, although in 2009, 3-O-acylated monoglucosides and p-coumaroylglucoside forms were more abundant in this treatment. A nonsignificant tendency toward increased total flavanols due to defoliation treatment was observed. Leaf removal increased concentrations of flavonols (glycosides of myricetin, quercetin, kaempherol, and isorhamnetin), hydroxycinnamic acids, and stilbenes in season-specific ways. Preflowering leaf removal may contribute to increased concentrations of compounds that can form complexes with anthocyanins (copigments) and may thus improve wine color stability
Nuclear Species-Diagnostic SNP Markers Mined from 454 Amplicon Sequencing Reveal Admixture Genomic Structure of Modern Citrus Varieties
Get PDFMost cultivated Citrus species originated from interspecific hybridisation between four ancestral taxa (C. reticulata, C. maxima, C. medica, and C. micrantha) with limited further interspecific recombination due to vegetative propagation. This evolution resulted in admixture genomes with frequent interspecific heterozygosity. Moreover, a major part of the phenotypic diversity of edible citrus results from the initial differentiation between these taxa. Deciphering the phylogenomic structure of citrus germplasm is therefore essential for an efficient utilization of citrus biodiversity in breeding schemes. The objective of this work was to develop a set of species-diagnostic single nucleotide polymorphism (SNP) markers for the four Citrus ancestral taxa covering the nine chromosomes, and to use these markers to infer the phylogenomic structure of secondary species and modern cultivars. Species-diagnostic SNPs were mined from 454 amplicon sequencing of 57 gene fragments from 26 genotypes of the four basic taxa. Of the 1,053 SNPs mined from 28,507 kb sequence, 273 were found to be highly diagnostic for a single basic taxon. Species-diagnostic SNP markers (105) were used to analyse the admixture structure of varieties and rootstocks. This revealed C. maxima introgressions in most of the old and in all recent selections of mandarins, and suggested that C. reticulata x C. maxima reticulation and introgression processes were important in edible mandarin domestication. The large range of phylogenomic constitutions between C. reticulata and C. maxima revealed in mandarins, tangelos, tangors, sweet oranges, sour oranges, grapefruits, and orangelos is favourable for genetic association studies based on phylogenomic structures of the germplasm. Inferred admixture structures were in agreement with previous hypotheses regarding the origin of several secondary species and also revealed the probable origin of several acid citrus varieties. The developed species-diagnostic SNP marker set will be useful for systematic estimation of admixture structure of citrus germplasm and for diverse genetic studies
Tetranychus urticae-triggered responses promote genotype-dependent conspecific repellence or attractiveness in citrus
No full textThe citrus rootstocks sour orange and Cleopatra mandarin display differential resistance against Tetranychus urticae. Sour orange plants support reduced oviposition, growth rates and damage compared with Cleopatra mandarin plants. Jasmonic acid signalling and flavonoid accumulation have been revealed as key mechanisms for the enhanced resistance of sour orange plants. In this study, we observed that the release of T.urticae herbivore-induced plant volatiles (HIPVs) from sour orange plants has a marked repellent effect on conspecific mites associated with the production of the terpenes -ocimene, -farnesene, pinene and d-limonene, and the green leaf volatile 4-hydroxy-4-methyl-2-pentanone. By contrast, T.urticae HIPVs from Cleopatra mandarin plants promote conspecific mite attraction associated with an increase in (2-butoxyethoxy) ethanol, benzaldehyde and methyl salicylate levels. HIPVs released from sour orange plants following T.urticae infestation induce resistance in Cleopatra mandarin plants, thereby reducing oviposition rates and stimulating the oxylipin biosynthetic gene lipoxygenase2 (LOX2). Cleopatra HIPVs do not affect the response to T.urticae of these rootstocks. We conclude that sour orange plants promote herbivore-induced resistance in Cleopatra mandarin plants and, despite the weak basal resistance of these rootstocks, herbivore resistance can be induced through the combination of HIPVs, such as -ocimene and d-limonene