ReDivia - Repositorio Digital de l'Instit Valencià d'Investigacions Agràries
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Physico-Chemical and Microstructural Changes during the Drying of Persimmon Fruit cv. Rojo Brillante Harvested in Two Maturity Stages
Get PDFThe physico-chemical and microstructural changes of “Rojo Brillante” persimmons in two maturity stages (S1 and S2) were evaluated during air drying. The maturity stage influences moisture loss. A Moisture level of approximately 50%, a limit at which persimmons are considered semidried, was reached after 21 and 28 days for S1 and S2, respectively. Shrinkage resulting from water removal led to secondary epidermis formation concomitantly to internal flesh gelling, which was related to moisture loss and water activity changes of each fruit part. The thicker epidermis and the lower volume of gelled area inside the S1 fruits led to harder fruit compared to the S2 fruits. The microstructural study revealed parenchyma degradation during drying in both the outermost area (secondary epidermis) and internal flesh, and this process was faster in S1 than in S2. The second peel presented hollows, generated by water outflow, which were bigger in S1 and explained the faster internal dehydration in S1. During drying, slight browning occurred, as reflected in the declining color parameters (L*, h* and C*). Water removal led to soluble solids tannin reduction to non-astringency values on day 28
Grafting onto an Appropriate Rootstock Reduces the Impact on Yield and Quality of Controlled Deficit Irrigated Pepper Crops
Get PDFIn this study, hybrid pepper rootstock NIBER® is tested for its ability to overcome water stress situations under soil conditions. The impact of deficit irrigation (DI) on yield and fruit quality, irrigation water use efficiency is evaluated, and consequently, the agronomic impact of employing water-stress tolerant rootstock is compared to ungrafted pepper plants. For this purpose, plants of the California-type sweet pepper ‘Maestral F1’ grafted onto NIBER® underwent a sustained DI regime during seasons 2018 and 2019 and were compared to their respective controls. Plants were drip-fertirrigated, and volumetric soil water content was continuously monitored by capacitance sensors. Gas exchange and leaf water potential measurements were taken early in the morning and midday 58, 79, and 114 days after transplanting. Plant and fruit dry biomass, marketable quality, blossom-end rot incidence and harvest index were also determined. For consecutive years, our results confirmed that grafting a pepper cultivar onto an appropriate rootstock (NIBER® in this case) as part of a DI strategy can overcome the negative effects of sustained water stress conditions. The plant biomass production and fruit yields of grafted plants were less affected by DI due to less sensitivity to water stress. This can be attributed to a less marked reduction in shoot dry weight in the grafted plants, which allowed greater whole photosynthesis by maintaining sink activity compared to ungrafted plants
Identification of Pomegranate as a New Host of Passiflora Edulis Symptomless Virus (PeSV) and Analysis of PeSV Diversity
Get PDFPomegranate is an important crop in the Mediterranean Basin that can be affected by a range of pathogens. With the aim to better understand the impact of viral diseases on pomegranate, two leaf samples from Turkey showing virus-like symptoms such as chlorotic spots and oak-leaf patterns were subjected to high throughput sequencing (HTS). Data analysis indicated the presence of passiflora edulis symptomless virus (PeSV: genus Roymovirus, Potyviridae family) in these two pomegranate samples, consistent with the observation by electron microscopy of flexuous filamentous viral particles 760 to 780 nm long. Further analysis of HTS reads revealed the presence of five PeSV variants in one of the samples and another single variant in the other. PeSV occurrence was also identified from publicly available SRA pomegranate RNA-Seq transcriptomic data from India and China. The genome of these PeSV-pomegranate variants share 78.0–86.8% nucleotide identity with that of the reference isolate from passionfruit (MH379332). The presence of PeSV in pomegranate was confirmed by specific RT-PCR assays targeting either the coat protein (CP) or Nla-Pro genes in 37 cultivated and one ornamental pomegranate out of 133 samples collected from the Eastern Mediterranean region of Turkey. To our knowledge, this is the first application of HTS to assess virus occurrence in pomegranate and the first recognition of pomegranate as a new host for PeS
Transcriptomic Analysis Reveals Salt Tolerance Mechanisms Present in Date-Plum Persimmon Rootstock (Diospyros lotus L.)
Get PDFAgriculture needs solutions for adapting crops to increasing salinity globally. Research on physiological and molecular responses activated by salinity is needed to elucidate mechanisms of salinity tolerance. Transcriptome profiling (RNA-Seq) is a powerful tool to study the transcriptomic profile of genotypes under stress conditions. Persimmon species have different levels of tolerance to salinity, this variability may provide knowledge on persimmon species and development of salt--tolerant rootstocks. In this study, we conducted a physiological and transcriptomic profiling of roots and leaves in tolerant and sensitive plants of persimmon rootstock grown under saline and control conditions. Characterization of physiological responses along with gene expression changes in roots and leaves allowed the identification of several salt tolerance mechanisms related to ion transport and thermospermine synthesis. Differences were observed in putative H+/ATPases that allow transmembrane ionic transport and chloride channel protein-like genes. Furthermore, an overexpression of thermospermine synthase found in the roots of tolerant plants may indicate that alterations in root architecture could act as an additional mechanism of response to salt stress. These results indicate that Diospyros lotus L. exhibits genetically-controlled variability for salt tolerance traits which opens potential opportunities for breeding salt-tolerant persimmon rootstocks in a Mediterranean environment challenged by drought and salinity
A semi-empirical model to predict the EM38 electromagnetic induction measurements of soils from basic ground
Get PDFElectromagnetic induction (EMI) measurements (σb*) are widely used for the survey of several soil attributes, among which basic properties such as salinity (σe),water content (θw), clay (wc), organic matter (wom) and bulk density (ρb) standout. In usual practice, purely empirical models relating one of these properties to σb* are calibrated at selected sites. However, this calibration is site and time specific and has to be repeated time and again. In order to understand where the variability of the EMI empirical models comes from, it is necessary to know how the different soil properties contribute to them and, with this aim, a more physically based relationship between σb* and, at least, σe, θw, wc, wom and ρb was developed in this work, additionally including soil temperature (t). It was calibrated and cross-validated with the data from one survey carried out in a wide agricultural irrigation area in SE Spain, taking σb* measurements with the Geonics EM38 in the horizontal and vertical dipole modes and at various heights over the ground. Then, it was externally validated with the data from a second survey carried out 4 years later in the same area but in a different season. In the calibration, R2 and root mean square error (RMSE) were 0.84 and 0.18 dS m−1(41%), respectively, forthe vertical dipole orientation and 0.90 and 0.11 dS m−1(39%) for the horizontalone. In the external validation, R2 and RMSE were 0.80 and 0.24 dS m−1(44%),respectively, for the vertical dipole orientation and 0.90 and 0.13 dS m−1(38%) for the horizontal one. Therefore, because the performance of the model barely worsened as time passed by, it can be considered to represent the underlying physicalprocess and, therefore, to increase our understanding of how the soil EMI signalsare generated, with potential benefits for the planning and comparability of EMI soil measurements, specifically with the EM38, among different areas
Diachasmimorpha longicaudata Parasitism Response to Medfly Host Fruit and Fruit Infestation Age
Get PDFThe parasitoid Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Braconidae) is increasingly being used in integrated pest management (IPM) programs as a biological control agent in order to suppress tephritid fruit flies of economic importance. Innate and acquired behavioral responses-such as pest host fruit preference-of parasitoids can modulate their efficiency in the field and should be taken into consideration prior to parasitoid species' selection for mass-rearing. We have assessed the influence of medfly-infested (two infestation ages, 1 and 4-d-old) and uninfested fruit species on host preference and efficiency of D. longicaudata by using a multistep assay including olfactory, laboratory and semi-field trials. We found that D. longicaudata was significantly more attracted to medfly-infested apples for both infestation ages, with the oldest being the most preferred. D. longicaudata exhibited a significant preference among the four fruits tested. The implications of these behavioral responses of D. longicaudata to medfly host fruits and infestation age are discussed in relationship to its use in IPM programs in the Mediterranean basin area
First Report of Penicillium ulaiense Causing Postharvest Whisker Mold of Oranges (Citrus sinensis) in Spain
No full textGenetic inhibition of flowering differs between juvenile and adult Citrus trees
Get PDFBackground and Aims
In woody species, the juvenile period maintains the axillary meristems in a vegetative stage, unable to flower, for several years. However, in adult trees, some 1-year-old meristems flower whereas others remain vegetative to ensure a polycarpic growth habit. Both types of trees, therefore, have non-flowering meristems, and we hypothesize that the molecular mechanism regulating flower inhibition in juvenile trees is different from that in adult trees.
Methods
In adult Citrus trees, the main endogenous factor inhibiting flower induction is the growing fruit. Thus, we studied the expression of the main flowering time, identity and patterning genes of trees with heavy fruit load (not-flowering adult trees) compared to that of 6-month-old trees (not-flowering juvenile trees). Adult trees without fruits (flowering trees) were used as a control. Second, we studied the expression of the same genes in the meristems of 6-month, and 1-, 3-, 5- and 7-year-old juvenile trees compared to 10-year-old flowering trees.
Key Results
The axillary meristems of juvenile trees are unable to transcribe flowering time and patterning genes during the period of induction, although they are able to transcribe the FLOWERING LOCUS T citrus orthologue (CiFT2) in leaves. By contrast, meristems of not-flowering adult trees are able to transcribe the flowering network genes but fail to achieve the transcription threshold required to flower, due to CiFT2 repression by the fruit. Juvenile meristems progressively achieve gene expression, with age-dependent differences from 6 months to 7 years, FD-like and CsLFY being the last genes to be expressed.
Conclusions
During the juvenile period the mechanism inhibiting flowering is determined in the immature bud, so that it progressively acquires flowering ability at the gene expression level of the flowering time programme, whereas in the adult tree it is determined in the leaf, where repression of CiFT2 gene expression occurs
Productividad física del agua y la tierra. Estrategias agronómicas para optimizar la eficiencia en el uso del agua y los nutrientes de los sistemas agrarios intensivos
Get PDFLa agricultura sostenible está basada en el uso eficiente de los recursos
naturales con el fin de salvaguardar el medio ambiente y proporcionar rendimientos
productivos que permitan satisfacer la necesidad de alimentos de una
población en continuo aumento (Tilman et al., 2002), objetivo prioritario de
la nueva agenda de la ONU sobre desarrollo sostenible (UN 2015).
De todos los recursos naturales e insumos que se emplean en la agricultura,
el agua es probablemente el factor más determinante de la productividad
de los cultivos (Matson et al., 1997). En la agricultura mediterránea, donde el
clima es semiárido, la disponibilidad de agua en el suelo es además la principal
limitación para la práctica de una agricultura económicamente sostenible; de
ahí que España posea la mayor superficie de cultivo en regadío de la Unión
Europea con cerca de 3,5 millones de ha (Eurostat, 2013). En este contexto,
el manejo del riego es el principal determinante de la calidad y cantidad de
las cosechas obtenidas. Además, una incorrecta gestión de los recursos hídricos
disponibles puede tener también graves repercusiones medioambientales
y socioeconómicas